Frequency Response

[Mr. Widget]

In an effort to put my money where my mouth is, instead of diverting yet another thread OT, I am starting this one inspired from a post elsewhere. We were discussing the 2397 horn with the 2441 driver and I posted the graph below which inspired this post:



Hey Widget-

In the range where it matters- that graph isn't nearly as contrasting as I would think it SHOULD be considering the price of the 4001. Does look a little smoother...The information that a frequency response graph gives us is limited. There have been many discussions around this topic with the posting of RTA curves, but I don't think the topic has really been covered. An MLS plot created by a system like CLIO with a calibrated mic gives us a bit more info, but it, like the RTA plot is really only an indication of performance. Primarily what you can get from looking at a curve like this one is an idea of a speaker's tonal quality. If you see a serious peak or dip you can infer that there may be a resonance issue or other problem, but realistically all we can tell is if the speaker will sound bright or dull, honky or more neutral... it really isn't nearly as all encompassing as so many seem to think.

When I posted this plot comparing the JBL 2441 and the TAD 4001, I said that the differences were "subtle and quite possibly not worth the big coin if cash is tight, but the inner detail and sense of dynamics is just that much better and they are slightly smoother." Tonally the two drivers were remarkably similar. You would gather that from looking at the plot. What you can't see is the way the 4001 with it's larger magnet and beryllium diaphragm has greater resolving ability which is quite audible. It also sounds slightly smoother and less fatiguing, but these differences are much more subtle.

The bottom line is that while a frequency response plot is helpful, don't put too much importance on it. Distortion and impedance plots are also useful, but as we have said countless times our own ears are the ultimate best judges of sound quality.

Widget

[Chas]

Hi Widget, does a TAD bolt up the same as a 2441?

[Mr. Widget]

It does. It is essentially Bart Locanthi's attempt at taking the 375/2440 and improving on it. It has similar geometry and is essentially the same design that Mr. Lansing himself created decades earlier. Bart increased the magnet and changed the diaphragm material. It even has the same roll surround as the 375/2440, not the diamond surround that JBL developed later.


Widget

[Mr. Widget]

This is posted elsewhere on these threads, but here is a JBL published comparison between the 2440, 2441, and the 4001. The discussion is about the mass break point and it's effects on HF response of compression drivers. For this discussion it is interesting to see how a different horn, in this case a JBL 2350 radial horn will have a dramatic effect on the FR curve of a compression driver.

Widget

[hapy._.face]

snip....In an effort to put my money where my mouth is...

I think you put your mouth where your money is...hell, who doesn't !? :p



snip...as we have said countless times our own ears are the ultimate best judges of sound quality.


....little wonder why some of that older (imperical) JBL sounds so good- even today.




An MLS plot created by a system like CLIO with a calibrated mic gives us a bit more info, but it, like the RTA plot is really only an indication of performance


I know it is elsewhere in this forum, but I'm glad you posted this again to put some fresh paint on it. I'm sick of hearing about the graph as the "end all". Sure, an RTA gives us insight to a driver's Fs and overall performance- but it won't tell you squat bout how it sounds!! Thanks!



Bart increased the magnet and changed the diaphragm material. It even has the same roll surround as the 375/2440, not the diamond surround that JBL developed later.


Flattering. ;)

[Titanium Dome]

...but nearly impossible to see how my receptors stack up to these transducers. It'd also be instructive to see how these transducers function in a real world environment.

This kind of solid work in understanding the subtleties of the interaction of magnet, diaphragm, horn, et al is the foundation to understanding the sonic characterisitcs of a system in a (more or less) standardized procedure.

I think we tend to like to do it so much because it's manageable, repeatable, consistent, comparable from unit to unit, etc. Plus we get to use really neat equipment. I admire those who have more skill, better equipment, and more dedication to this endeavor than I.

Thanks, Widget, for sharing this.

Widget's assertion that the ears are the ultimate judge is irrefutable and shows that he's both a man of science and of common sense--a useful commodity indeed.

[norealtalent]

...
If the LH weekend happens this summer, maybe I'll invite an audiologist to offer hearing analysis for attendees. That should be an eye--and ear--opener! :D Maybe it'll finally reveal what I've suspected all along about those who prefer horns...but I'm getting off thread here.

Whatdyashay? Speak up sonny, I can't hear ya!;)

[edgewound]

...

If the LH weekend happens this summer, maybe I'll invite an audiologist to offer hearing analysis for attendees. That should be an eye--and ear--opener! :D Maybe it'll finally reveal what I've suspected all along about those who prefer horns...but I'm getting off thread here.

What is it that you suspect? That horn-preferers have some sort of physical defect? Boy oh boy... you set yourself up for this one. Some listeners...probably most listeners... will prefer the system that sounds best to them....I've heard both....and I like both if they're respectivley done well. Your agenda is showing;) .

[hapy._.face]

...but nearly impossible to see how my receptors stack up to these transducers. It'd also be instructive to see how these transducers function in a real world environment.

It would, indeed.



....maybe I'll invite an audiologist to offer hearing analysis for attendees. That should be an eye--and ear--opener! :D Maybe it'll finally reveal what I've suspected all along about those who prefer horns...but I'm getting off thread here

Good idea! I worry about your iPod's ill effects on YOUR hearing! (insert a big smiley face here)

[Robh3606]

Since this is a forum about Lansing Heritage, it's obvious we'll spend most of our energy on the speakers themselves. However, we do neglect our rooms and our ears to a great degree.

Why would you think that???? Anyone who is serious about this hobby tends to be more careful than most about what they will expose their hearing to. Especially as you get older where it's only a matter of time that age takes it toll. Last thing you want to do is help it along!


If the LH weekend happens this summer, maybe I'll invite an audiologist to offer hearing analysis for attendees. That should be an eye--and ear--opener! :D Maybe it'll finally reveal what I've suspected all along about those who prefer horns...but I'm getting off thread here.

Your kidding right??

Rob:blink:

[JBLnsince1959]

What is it that you suspect? That horn-preferers have some sort of physical defect? Boy oh boy... you set yourself up for this one. Some listeners...probably most listeners... will prefer the system that sounds best to them....I've heard both....and I like both if they're respectivley done well. Your agenda is showing;) .

Yeah that would be first for Dome wouldn't it...:rotfl:

[jim campbell]

many years ago someone showed me a graph comparing a very expensive studio tape recorder ($150,000.00) and a mass market cassette deck valued at about $300.00. the studio machine did not even note frequency response above 15khz.the specs on the cassette deck were actually better than the studio rig.some time later a friend with a frequency generator showed me just how fast sounds roll off above about 12-14khz.after that i always put very little stock in graphs and spec sheets and believed my ears.

[DavidF]

After five years on this forum I'd put very little stock in most of the ears here. :p

Well, ok, maybe a wee bit - after all, you all seem to be able to tell the difference between an Altec or JBL and everything else. ;)

Say what? My ears are very discriminating. They just don’t always like what they see.

Davidf

[Ian Mackenzie]

Widget,

Is it possible to post a near field unsmoothed response comparison and also distortion curves for the respective drivers?

Ian

[Mr. Widget]

Near field... these were taken at 1m on axis with 1/12th octave smoothing. This level of smoothing removes very little information. The main reason that they look fairly clean is that they are time windowed which eliminates all of the hash that you normally get with a pink noise curve. I should have placed the horns higher from the floor (I have slightly over 10' ceilings) to extend the time window. With this window the information below about 800Hz is meaningless.

Since I no longer have either the 2441s or the 4001s... had to sell them to try other items, I can't make the other measurements. Sorry.

The point of this thread was to explain that a simple FR plot really doesn't tell that much of the story. Impedance plots and distortion curves will get you another 10% there, but you are really still way off in the dark.

Widget

[scott fitlin]

I dunno, I read, and read, and always read more, I play with different things, and differing brands, I look at graphs and specs, and claims and so on. But, in the end, its ALWAYS my ears as my final judgement and decision maker. Too many times, I have read the specs, and according to them, the drivers are this and that, get em into your system, and for whatever reason, they do something you werent aware they would, or dont do what the specs led you to think they would.

I know what I like, and I know when I hear it, and If I like what I hear, I almost dont even care what the spec sheet says!

I just got done re-installing my JBL 2441,s. I JUST had to play with my TAD 4002,s again, so I did.

Whatever JBL did when they made this series ( 2440 and 2441 ) they did right, really, really right, and even if the graph says otherwise, my ears tell me I love my 2441,s!

:)

[Steve Schell]

This is a great discussion Widget; I just hope that it doesn't get derailed by red herrings such as whether people who like horns can hear well. I agree completely that a frequency response curve tells only a small part of the story. It seems that in audio the measurements that have become the standards are those that are easy to make, not those that might be the most telling.

When Wente first designed his experimental driver that was later reincarnated as the Western Electric 594A and JBL 375, I believe that he was trying to obtain perfect pistonic behavior of the diaphragm to the extent possible. As designs have progressed (regressed?) into the modern era, designers have encouraged and embraced suspension resonances as a means of extending high frequency output. This works on paper, but tends to result in tizzy, fatiguing sound quality. The response measurements look great, but the listening can be awful.

I believe that it is no coincidence that many critical listeners prefer drivers that use Wente's simple half roll compliance. The W.E. 594A and 713 series, the Lansing Mfg. Co. large and small format drivers and the JBL 375/2440 all used this elegant design. The half roll is not perfect, as the paper you referenced pointed out; there is a broad resonance that extends response on the top end. Seems to me though that it is generally more benign and relatively well behaved than the tangential and especially diamond pattern surround resonances, which I suspect are more peaked and narrow in frequency.

For years now I have preferred a response that is rolled off over one that is extended with such parlor tricks. Diaphragm material also makes a big difference, as we all know from listening to aluminum, titanium and beryllium diapgragms in otherwise fairly similar drivers. I have become most fond of composite diaphragms, which seem to self-damp to a greater extent than metal diaphragms and sound cleaner as a result. Most audiophiles have shunned these due to frequency response limitations, but there is still much potential in this approach. Some of the best sounding vintage tweeters, such as the EVs and the Jensen RP-302, used linen and phenolic diaphragms.

BTW, is the JBL technical paper easily accessible? Is it up on our site somewhere?

[Ian Mackenzie]

Steve,

I like what you post...your insights are impressive!

On the subject of diaghrapm damping as you say it plays a big part in tonal quality and rendering of fine details based on my recent experience.

I recently opened up my 2420 for a new diaghragm and it was quite educational to watch the pistonic behaviour under drive condition not normally associated with in use application.

Ian

Ian

[scott fitlin]

Hi Steve, always good reading, you provide!

I have been reading your post about your Cogent drivers. When will these be available?

Years ago, a freind of mine had some JBL 1in drivers that used a linen/paper type diaphragm, they were white color, and they did have a distinct sound in the midrange!

I got eyes for those beauties your making!

[Mr. Widget]

BTW, is the JBL technical paper easily accessible? Is it up on our site somewhere?Here it is:

http://www.audioheritage.org/vbulletin/showthread.php?t=4410

I have wondered about the surrounds too. I have used the 2440, TAD 4001, and TAD 4003 all with the half roll surrounds. I have used the 2441s with their diamond surrounds and have listened to many of the JBL Ti diaphragms with their diamond surrounds, and I have also used the Altec Symbiotic and Meyer Sound drivers with their mylar surrounds. I feel I can make generalizations about Ti vs. AL vs. Be, but I am not comfortable making generalizations about the surrounds.

Widget

[scott fitlin]

FWIW, I have some 2440,s. Ive looked at the half roll surround, and Ive listened to them. They do have a 9K peak, gives this driver a high pitched sound up there, I always thought a bit more so than the `41. I like them, and theres yet another driver with a half roll surround I like too, the Gauss HF4000.

Many guys used to say the Gauss had the sweetest sounding upper mid, all I know is, you listen to three different drivers, and they all sound different, pick the one you like!

I also liked the Altec 288,s! and as I said, they all sound different from each other.

[Zilch]

I'm sick of hearing about the graph as the "end all". Sure, an RTA gives us insight to a driver's Fs and overall performance- but it won't tell you squat bout how it sounds!! Well, yes, but the corollary is also true: If you don't have the requisite FR, it doesn't matter -- you don't have squat to begin with....

[Mr. Widget]

Well, yes, but the corollary is also true: If you don't have the requisite FR, it doesn't matter -- you don't have squat to begin with....I absolutely disagree. I quite possibly may have made that statement myself a few years ago, but having listened to some very fine speakers with seemingly terrible response curves and some absolutely crap speakers that measure virtually textbook perfectly... no the corollary is not true.



Widget

[Zilch]

I quite possibly may have made that statement myself a few years ago, but....You may be a couple of years ahead of me, then, but, for now, you'll not convince me it's all a wank. :no:

BTW, we probably should distinguish between drivers vs. systems here.

[I'll admit I don't understand the THX "X-Curve," tho....]

[Steve Schell]

Ian, I do think that suppression of resonances plays a big part in lifelike reproduction. This applies to well behaved suspensions as well as the behavior of the major piston area of the diaphragm. An exciting aspect of all this is that compression driver design is still a young science, and I feel that many improvements in these aspects are still possible. Having said that, a major reason that we like compression drivers on horns to begin with is that these distortions tend to be lower than with competing driver technologies, due to the heavy loading and tiny excursions.

Widget, thanks for the URL. I have found also that there is sometimes little correlation between smoothness of frequency response, measured bandwidth and perceived quality of sound. One time my friend Rich and I listened to three cone speakers in mono on the same Voigt pipe: an RCA 8" full range with Olson's dual voice coil, a 6" Fostex full ranger and a 4" Jordan aluminum cone full ranger. The RCA sounded best overall, very lively with the greatest subjective high frequency extension. Next was the Fostex, not as lively but still pretty good. The Jordan suffered by comparison, sounding constrained and lifeless. When we ran LMS frequency response curves we were in for a surprise! The Jordan had low sensitivity but awesome f.r., nearly ruler flat to 18kHz. The Fostex had higher sensitivity, fairly flat response that died above 14kHz. or so. The RCA had the highest sensitivity by far, but dropped off rapidly above 8kHz.

Scott, thanks for asking about the Cogent drivers. There has been great progress recently. Rich revised our voice coil winding tool, and we have made changes in materials as well. Sensitivity of the midrange driver is up by 2dB and the sound has improved as well. Our main logjam has been in completing the patent application on our phasing plug, and it was finally mailed to the USPTO today. We are about to ship drivers to our first customer, and are in the midst of our first small production run.

Note: my comments on the benefits of composite diaphragm materials need to be taken with a grain of salt, as I am involved with a company selling same! I do feel, though, that the original RCA design of the center-suspended cone compression driver is possibly the most noteworthy and underutilized invention in the world of compression drivers. Imagine a driver with a 4.5" cone for a diaphragm, with a 2" voice coil located midway between center and edge and a cloth skirt for an outer suspension. The diaphragm is damped like crazy, between the basic construction, cloth surround and choice of materials for the diaphragm. RCA's original was silk cloth and phenolic resin, ours is carbon fiber and epoxy. The bandwidth is unreal; the diaphragm resonance is 125Hz., and use to 200Hz. is entirely possible with the right crossover. With our improvements to the RCA radial phasing plug response is fairly flat to 10kHz., and usable above that with EQ.

I will be able to say more about all of this once our patent application is acknowledged by the USPTO. We plan to launch our Cogent web site soon; I will announce it here.

Know how to become a millionaire? Start with two million and go into the speaker business!

[Mr. Widget]

You may be a couple of years ahead of me...This isn't a competition. I see it as a shared journey.:)


...you'll not convince me it's all a wank. :no:That wasn't my point. All I am saying is that we tend to put too much value in these simple curves. They are not irrelevant, not at all. But you need to open your mind to the possibility that when objective listening is also used, you may find that the speaker with the flatter response may not be the one that we would prefer to listen to. I am not talking about room curves or tonal preferences. I am saying that there are other important aspects to sound quality too. Think about those beautiful specs coming from the 70's amps with gobs of negative feedback. Most of us would agree that an amp with less negative feedback and poorer specs SOUNDS better.



BTW, we probably should distinguish between drivers vs. systems here.
Agreed. It is much easier to glean useful info on a simple driver curve than one from a multi-way speaker system... and more difficult still to glean useful information with a full range system taken in a reverberant room.


Widget

[Ian Mackenzie]

Steve,

Another great post bringing fresh new insights into the thread.


Ian

[Robh3606]

That wasn't my point. All I am saying is that we tend to put too much value in these simple curves. They are not irrelevant, not at all. But you need to open your mind to the possibility that when objective listening is also used, you may find that the speaker with the flatter response may not be the one that we would prefer to listen to.

Hey Zilch

I have 3 systems I can set up to measure the same and they all sound different. Even set up for flatest on axis response. It's useful information but doesn't tell the whole story. Do you really think an L20T/4406 and a 4344 sound the same?? Above 60 Hz you can get them surprisingly close and the L20 has the smoothest response. The 4344 can eat them alive. So Widget I agree it's useful but not the whole story.

Rob:)

[Ian Mackenzie]

Giskard,

Time step function on the FFT might be an indicator of damping.

My tests of the horn out of the box the other day were remarkably clear of aberrations if you know what I mean.

Ian

[scott fitlin]

So what shall we do? Brush up on adjectives and adverbs instead of relying so much on visual aids I suppose. :p:yes:

[scott fitlin]

No, actually I agree with you, it really isnt! However, I am of the opinion, that audio manufacturers strive too much for what looks right on the scope, and extreme power handling, and unfortunately, this doesnt always = good sound, let alone better sound!

There are so many avenues of discussion opened up by this thread. Look at amplifiers! Same thing. The numbers just dont tell you what the amp sounds like, or how it performs! An example ( IMHO ) is many of todays very compact and lightweight switching amps, rated at 1500wpc, and beyond, damping factors in excess of 1000, some well over 2000, and yet, dont seem to produce the power and tight bass of some older, traditional amplifiers, despite their specs seemingly limited technical proficiency!

Many things audio today, they get it so technically correct, and so musically wrong!

You know, since I am in NY, and close to NYC itself, I have been to Radio City Music Hall, I saw Pink Floyd there, in 1978 or 79, what an incredible show. And that is my favorite sounding concert of all time. Of the ones I have seen!

Now, lets take Carnegie Hall, a great hall, known for its acoustics, and they just HAD to redo it, something wasnt right! And when they were done? They had succesfully RUINED Carnegie Halls famous acoustic sound! All through the 90,s they came in with their computers, and Gee Whiz technology, valiantly trying to restore the sound of that room. They blamed the contractors for using the wrong materials, doing the job wrong, etc! BUT, the one thing they have NOT been able to do? Restore the sound of the room that Carnegie Hall had! All the technology, and all the fantastic minds at work, but they couldnt put it back together again!

Measurements dont tell the whole story.

[hapy._.face]

I mentioned it earlier (in part), that I suspect FR curves are aimed more at strategic marketing campaigns. With the aforementioned 'parlor tricks'- a manufacturer can make anything look good on paper. Who knows what scientific variables were ignored or exploited for the sake of producing agreeable graph readouts? Giskard- thank you for posting the JBL disclaimer scan; I was looking for that- I knew I read it in my L212 manual.

This brings me to another important point- there are so many other variables we often overlook in our quest for the ultimate sound. I am amazed at how some people cannot appreciate a flat responding system even when it's playing in front of them. Perhaps anomalies in their own hearing can make a person feel as though they are hearing something lifeless and dull. What is the point of pursuing something to such financial strain- only to behold the irony that the pursuit was in vain? If I cannot see the 30% peripheral- why would I purchase my own IMAX screen? Know what I mean?

I'm also amazed at how a person can listen to a system at a friend's house (using components a, b, and c), then walk into a shop and listen to another system (using components d, e, and f), and have the audaciousness to make wholehearted statements about ANY of the components in question. The variables to which each performed are so numerous- I won't waste time to mention them here. You don't have to be an audio expert to understand the basics of scientific research and methodology.

In the end- people want to hear different things. We all process sound differently. Years ago, Range Rover posted a famous magazine ad in which many of the letters of the opening lines were missing. They must have done a great deal of research on what words to use because the reader (myself included) didn’t realize the letters were missing; It was read just as anything else was. The ad then stated that '...you'll never know what's missing' as an indication of the truck's fine suspension and how it can decouple you from the hazards of the road. That always stuck out in my mind as the perfect analogy to hifi. We often "fill in the blanks" when we hear things.

Ultimately- we don't all pursue the same game. Thank you for that! Otherwise all the stuff I want would be pursued by countless other millions and be WAY out of my (our) price range! I'm thankful that JBL has a bad rap in snobbish circles- keeps the older stuff somewhat affordable (for now). A person listening to an overly exitable system may find it sounds perfect when combined with hearing limitations. I wonder why there isn't a bigger industry to correct a person's hearing. We could all have perfect hearing for a few hundred bucks (say, for example) and level the playing field. Then what would our audio conversations be like? Hmmmm....?

[scott fitlin]

I do not agree that flat response is always the best. granted, there are varying degrees, of whats right and whats not, and gross frequency exaggerations or under accentuations can make bad sound, perfect, technically correct, flat response just guarantees that its flat! It doesnt tell you how the speaker sounds, or mean that you will automatically like it.

[Ducatista47]

"...(Speaker System) balance can be established by adjusting levels to achieve the flattest response as measured with a real-time analyser and a pink noise source... Alternately, subjective evaluation of familiar program material can provide a good means to balance levels. In fact, perfectly flat electro-acoustic response is seldom desirable for the listener, so subjective evaluation may be the preferable technique."

Quoted from the 5235 Manual. Emphasis mine. I do admit to a disdain for pure meter (only) men, so I am not impartial in these matters.:) I know this was written about balancing speaker bi-amping, not response of individual transducers, but I feel it has broader implications. In the case of a two way system, it applies a bit more directly, of course.


Clark in Peoria

[hapy._.face]

I do not agree that flat response is always the best. granted, there are varying degrees, of whats right and whats not, and gross frequency exaggerations or under accentuations can make bad sound, perfect, technically correct, flat response just guarantees that its flat! It doesnt tell you how the speaker sounds, or mean that you will automatically like it.

Understood. good point.

I prefer a flat system because I like to judge the music and recording techniques used other than the gear. I'd rather say 'Rick Rubin has an ear like the sandwich', rather than saying 'my cd player sounds jacked up'.
I know not everyone wants the same..

I quote myself here again with emphasis on the word appreciate:



...some people cannot appreciate a flat responding system even when it's playing in front of them. Perhaps anomalies in their own hearing can make a person feel as though they are hearing something lifeless and dull.


It does not always mean it sounds musical, agreed. I should have added that. Perhaps my words were not carefully chosen, but I hope you get the point.

[JBLnsince1959]

but having listened to some very fine speakers with seemingly terrible response curves and some absolutely crap speakers that measure virtually textbook perfectly... no the corollary is not true.
Widget

Hey Zilch

I have 3 systems I can set up to measure the same and they all sound different. Even set up for flatest on axis response. It's useful information but doesn't tell the whole story. Do you really think an L20T/4406 and a 4344 sound the same?? Above 60 Hz you can get them surprisingly close and the L20 has the smoothest response. The 4344 can eat them alive. So Widget I agree it's useful but not the whole story.

Rob:)

I would agree with these gentlemen....

Measurements are useful, but we have to make a distinction between measuring the PERFORMANCE of a speaker and the subjective listening experience... the two are not the same....

There's a saying in certain intellectual circles..."The Map is not the Territory"
I can read a map and know it backwards and forwards, but no matter how well I've studied the map...it ain't the same as walking ( or driving) the same route.

measurements can only tell us how a particular object performs within certain define paramaters..it's usually a graph of relationships between two or more ABSTRACT definitions used to convey certain agreed upon units of measure for some physical phenomenon....

so to put it simple....measurements of any kind can only tell us how it performs...it can not tell us if the sound ( in this case music) will be enjoyable

[hapy._.face]

We're doing it! Somehow- we are managing to stay ON TOPIC!!!

[JBLnsince1959]

We're doing it! Somehow- we are managing to stay ON TOPIC!!!


:banghead: :banghead: :banghead:,

as soon as you posted that we strayed off topic....:rotfl:

[norealtalent]

Yes, I'd like eggs and toast for breakfast please. Thank you.;)

[hapy._.face]

Can the ambient temperature of a room affect a FR readout to any discernable degree (pun intended)?
What about the temperature of the driver itself?

[Titanium Dome]

A lot of folks, and I mean A LOT, who have never heard the K2 S9800 look at the response curves and judge it a monumental waste of money and a stupendous failure.

"Look at that graph! Is that the best that JBL can do? They want how much for a speaker that can't even handle 35Hz decently?"

The probelm is that the graph is the only thing accessible to them, so they use what they can see to determine what they will hear. If they ever heard the speaker, they'd know the graph was irrelevant.

In the "pre-dawn" phase of audio awareness, the average consumer looks not listens.

The consumer looks at
specs
finish (is that real maple?)
size
driver size
visual design appeal
brand name
price
power handling
how it goes with their furniture
how it goes with their color scheme
how it will fit in the spot they've visually chosen for it

There are probalby more. Feel free to add. The point is that all these "vision things" are settled for the "research based" ("I looked it up on the Internet.") consumer who trusts what he can see over what he will hear.

[JBLnsince1959]

so I guess another way to say this is.

that using a double blind study where no one in the test knows the measurements of two speakers and gets a person who values ruler-flat measurments( or other measurements)....it is possible to to find two speakers that measure close enough to not make a difference and for the subject to enjoy one speaker and not the other....

now let me say that I'm in no way saying that the measurment may not have an inpact on the subjective nature to a particular individual( as far as the listening experience - they don't know the measurments)....there will be that dynamic interchange between the listener and the speaker, and that get's a little complicated to quantify, however.......

That type of situation can best be understood using systems theory and using the particular aspect of - any change no matter how small to any one part of the system will change the entire system to something new. With the understanding that we define our system as the speaker, the total environment and the listener...however, I don't have the time aright now as this would take some time.... maybe I can work that out in my spare time and then we can prove this when we get a group together.

[JBLnsince1959]

Can the ambient temperature of a room affect a FR readout to any discernable degree (pun intended)?
What about the temperature of the driver itself?


dicernable degree,? I don't know...does it affect it at some level..yes.. notice what I said in discussing systems theory....

[JuniorJBL]

Can the ambient temperature of a room affect a FR readout to any discernable degree (pun intended)?
What about the temperature of the driver itself?

I would think so because it would have to do with air pressure as well.
Listening to a system up here in Denver is way different than in California.
I have noticed for quite sometime that many systems sound better with different temperatures as well.

This went back to my car audio install days when this made even a bigger difference because of the large temperature variation in a car. Mornings always sounded better!!;)

[JBLnsince1959]

Mornings always sounded better!!;)

are you sure it wasn't the coffee...:D

[scott fitlin]

"Look at that graph! Is that the best that JBL can do? They want how much for a speaker that can't even handle 35Hz decently?"

The probelm is that the graph is the only thing accessible to them, so they use what they can see to determine what they will hear. If they ever heard the speaker, they'd know the graph was irrelevant.

In the "pre-dawn" phase of audio awareness, the average consumer looks not listens.

Yes, this is very true, but, its also what the marketing and advertising depts from audio manufacturers have TAUGHT, or rather " Trained " most of the gullible public into believing what they need!

How many years have they been rating speakers FR as 20hz-20khz? Lets go back 30 years, many speakers rated to get down to 20hz were like what? -25db at that frequency?

Marketing and advertising are very powerful tools, make it eye popping, and it will sell. Arent there many gorgeous speakers, that dont sound nearly as good as they look? Give them that BIG macho woofer, he will go for that, and put it in an elegant mahogany, phallus shaped cabinet, SHE will go for that! And how much pro and theater gear looks like industrial junk, but sounds incredible?

How many people REALLY understand frequency, and what frequencies voice, instruments, etc, occur at?

JBL used to put out a record that contained sounds, and told you what frequency these sounds happened at! 63hz sounds alot deeper than the number implies! At 40hz, you hear and feel air moving, but not too much else!

I used one of those Bass Test CD,s once, this was when I first got the J Horns, to see what they could do. The CD contains 20, 25, and 30, and up tones. Once I got down to 30hz the sound I could hear was getting weaker, it was audible, but not nearly as much as 45hz or 50hz, and 60 to 80hz. Down below 30hz, into the 20,s you could feel it, but couldnt really hear it. The 20hz tones throguh the J Horns produced output that my RTA could read, and it was up there in db, and I could feel it, but I could NOT hear it! No matter how loud I turned it up, I heard nothing but the room rattling! Surprisingly, the woofers were not bottoming. But, real music rarely has any content this low. Especially pre-recorded music.

I know one thing, what many people think is sub bass, is NOT sub bass!

[scott fitlin]

I would think so because it would have to do with air pressure as well.
Listening to a system up here in Denver is way different than in California.
I have noticed for quite sometime that many systems sound better with different temperatures as well.

This went back to my car audio install days when this made even a bigger difference because of the large temperature variation in a car. Mornings always sounded better!!;)During the summer months, go out onto a golf course early in the morning with another person. Two people can talk to each other from great distances without raising their voices, and hear each other clearly, early in the morning because the cool air is close to the ground, and the warmer layer of air ontop. This carries sound over a greater distance without having to raise your voice.

Conversely, in the afternoon, when the bottom layer of air is warmed up, and the top layer is hot, the sound no longer carries over the distance!

[JBLnsince1959]

How many people REALLY understand frequency, and what frequencies voice, instruments, etc, occur at?

JBL used to put out a record that contained sounds, and told you what frequency these sounds happened at! 63hz sounds alot deeper than the number implies! At 40hz, you hear and feel air moving, but not too much else!



agree completely...and another thing that many don't realize is that once you reach a certain level, bass notes are NOT preceive primarily from their fundamential note but MOSTLY ( and completely at some point) from their harmonics ( or particals)...this is true of the lower notes on a piano......

[JBLnsince1959]

During the summer months, go out onto a golf course early in the morning with another person. Two people can talk to each other from great distances without raising their voices, and hear each other clearly, early in the morning because the cool air is close to the ground, and the warmer layer of air ontop. This carries sound over a greater distance without having to raise your voice.

Conversely, in the afternoon, when the bottom layer of air is warmed up, and the top layer is hot, the sound no longer carries over the distance!

Well, that explains why when someone is Bullshitting me and producing a lot of hot air, I tend not to really hear what their saying...

[Mike Caldwell]

Here's different take on frequency response plots, charts and how something really sounds. Just recently I had some extra time to do a test I had been thinking of for a while measuring various microphones that I use for my live audio productions. The set up was a small monitor, pink noise generator, SMAART Live. Using the calibrated measurement mic to get a reference plot then swapping the ref. mic with many different kinda of mics that I have. I was surprised of how close a wide variety of the mics all showed a very similar response to the ref. mic. You could see the mics that have a rising response, enhanced low end ect.

What is comes down to while the response plots for the mics looked close to almost the same in many cases used in the real world they all have vary different voicing/sound quality.

The testing was done using the transfer function test and also displaying the phase plot and the mics were placed the same distance from the monitor pointed at the same spot. On couple of the mics the phase plot showed more of what the mic was doing than the frequency response.

Mike Caldwell

[scott fitlin]

Well, that explains why when someone is Bullshitting me and producing a lot of hot air, I tend not to really hear what their saying...OK, Ill go for that!

:applaud:

[hapy._.face]

I have an audition scheduled for the K29800 in NJ. I have said it earlier- I find it to be the best conceived speaker JBL has made to date (IMO). This is based on my perceived logic- and little on expert opinion. It just seems right to me in so many ways- all without hearing it yet. If I find my listening experience to be equally "right", I will have to own a pair. I like speakers more than cars, so I've already justified the price. Why waste my time and effort tracking down a "this" and "that", when (if I love it) a K2-9800 does it all out of the box? I'll be "done" in the speaker dept for a long while, I think.

OK- bring on the critics....

[Mr. Widget]

A lot of folks, and I mean A LOT, who have never heard the K2 S9800 look at the response curves and judge it a monumental waste of money and a stupendous failure.

"Look at that graph! Is that the best that JBL can do? They want how much for a speaker that can't even handle 35Hz decently?"

The probelm is that the graph is the only thing accessible to them, so they use what they can see to determine what they will hear. If they ever heard the speaker, they'd know the graph was irrelevant.
Personally I thought the published plot looked pretty good, beyond that a portion of a review of it from Stereophile on-line has been quoted here a couple of times and in it they show a plot of the K2-S9800 that they did in-room along with several other expensive speakers and they said that the JBL produced one of the flattest in room responses they'd seen or something to that effect.

I don't think anyone will buy or not buy a speaker based on a graph... and they shouldn't.



I'm also amazed at how a person can listen to a system at a friend's house (using components a, b, and c), then walk into a shop and listen to another system (using components d, e, and f), and have the audaciousness to make wholehearted statements about ANY of the components in question. The variables to which each performed are so numerous- I won't waste time to mention them here. You don't have to be an audio expert to understand the basics of scientific research and methodology. Absolutely! I laugh when I hear someone audition a friend's new CD player via an entirely unfamiliar system and pronounce the CD player as a clear masterpiece...:bs:



I prefer a flat system because I like to judge the music and recording techniques used other than the gear. I'd rather say 'Rick Rubin has an ear like the sandwich', rather than saying 'my cd player sounds jacked up'.
I know not everyone wants the same..While I would agree with this statement it isn't actually what I was talking about. This has more to do with a room curve or tonal color. Some people for example prefer the jacked up mids of a vintage Altec system.. that's cool, but not really what I was trying to talk about here.


I have an audition scheduled for the K29800 in NJ.... (if I love it) a K2-9800 does it all out of the box? I'll be "done" in the speaker dept for a long while, I think.

OK- bring on the critics....Excellent! That is exactly how we should approach these things. Listen carefully and if it sounds right to you, plop down your money. Ideally you can take them home and listen to them in your room with your gear. I know from having worked with the 1500AL that they won't satisfy my bass needs in my large room. You may find that they are indeed just the ticket for you.

Widget

[scott fitlin]

Whats to criticize?

If you are liking what you read about them, and the reviews and advertising claims lead you to audition them, and you love them, thats how you do it. And if you can have an in YOUR house audition for a week, even better!

You dont have to justify the price, to anyone, as long as you can afford them, and want them, get them!

[Steve Schell]

One aspect of making measurements that I was unaware until recently is the difference between pink noise and white noise. According to this fellow Mark Taw's web site (link below), pink noise contains equal energy per octave, while white noise contains equal energy per frequency. A frequency response plot of white noise would be a straight line (flat response), whereas pink noise would plot out as a downsloping line that would fall by 3dB per octave across the entire audio band.

How many systems have I balanced with pink noise to give a "flat" response? Too many to count. At least according to Taw's description, I was setting them for a rising response. Indeed, they have frequently sounded too bright for me. Could widespread misunderstanding about this be partially responsible for the audibly tilted up response of so much modern gear? My current system displays pretty much a flat response with white noise using a handheld 1/3 octave RTA, and a gently downsloping response with pink noise. It sounds about right to me.

Guys, does your understanding of pink noise vs. white noise agree with Taw's?

http://www.marktaw.com/recording/Production/ThroughTheDecades2.html

[jim campbell]

maybe when the yardsticks that the industry uses to measure performance conform to some recognizable standard we can put more faith in them.

[Titanium Dome]

Yes, that basically is what I've thought since I got my first Soundcraftsmen AS1000 "Scan-analyzer" twenty-five or thirty years ago. The typed instruction manual made specific mention of the distinction and how to utilize the AS1000's functions correctly.

[Robh3606]

How many systems have I balanced with pink noise to give a "flat" response?

Hello Steve

I must be missing the boat on this but pink noise is what you would use with an RTA to set for flat in room response. If you tried to use white noise with an RTA and set the band flat or equal you would end up with a falling response. That may sound more natural and actually that is a nice way to get a gradual falling response curve. The RTA is set up for same power in each band not a linear one because of the doubling frequency range in each octave. What you are doing is rolling off at 3Db per octave.

Rob:)

[Mike Caldwell]

In general a falling response is what sounds better to most ears still of good hearing. There is a guide line formula of starting at a certain frequency and a falling at so many db per octave that is a inverse curve to the response of an average humans hearing. I can't remember the numbers though. Putting that curve on a system in sense gets flattened out whne our ears and brain here the sound. As was said a system that measures flat ( give or take a couple of db) may not really sound that good to listen to.

Mike Caldwell

[Zilch]

O.K., here, again, is the K2 in-room response curve, which Stereophile deemed "exemplary." Note that it is not "flat," but it is "straight."

I also refer these discussions to the extensive work JBL has done in the area of subjective testing, posted or linked SOMEWHERE on this site: statistically, the flattest response wins out in listening comparisons. The Stereophile papers (also linked on this site,) on their own loudspeaker testing methods and results say the same.

Flat with titanium-diaphragm compression drivers is too "bright" for me, too. With aluminum, damped, and mylar diaphragms, I find that I prefer flat. I like to think, lately, that I understand why.

For more consternation, see the THX X-curve, ISO Document 2969 for large cinema....

[Mr. Widget]

Now that you have all diverged and headed into the "room curve" direction, I'll say that I too have found that a straight line that falls approximately 10dB from 20Hz to 20KHz is what I have found to sound "most natural". That said, we use software (prerecorded music) that was most likely designed for just such a curve. So I am not sure that we really do prefer a falling response.

In any case we are discussing several loosely related topics.

Thanks Rob for posting the info on pink vs. white noise. I meant to get back to Steve's post but gosh darn it I keep having to get back to work.:(


Widget

[Steve Schell]

Rob, thanks for your informative post. So then it seems that a flat line is what we are looking for after all when measuring pink noise with an RTA.

Mike, I agree that a gently falling response sounds best, at least to me. I have heard various theories over the years that an ideal response falls at 2 or 3dB per octave above 2kHz. or some such.

Zilch, that curve you posted falls at about the same rate that I am seeing in my room at present, when measured with pink noise. I have tried straightening it out with the parametric EQ function of the DEQX, but it sounds too bright to me.

This probably all relates also to our earlier discussion of diaphragm resonances. I once asked Dr. Bruce Edgar about all this, and he said "Flat response would sound fine if it was clean." Problem is that most drivers do not reproduce the top octave cleanly, without artifacts that are grating to the ear.

Widget, when all is said and done we might have to conclude that the response curve that sounds best IS best, which I think is in harmony with your first post!

[Titanium Dome]

Included in this very positive and illuminating review of the K2 S9800

http://www.ultraaudio.com/equipment/jbl_k2_s9800.htm

is a bit on the topic at hand:


My in-room measurements were very promising indeed. Placed well clear of walls, the K2 delivered unusually smooth and flat far-field traces, with a close-to-ideal, gently down-tilted overall characteristic. There is a little too much output around 500Hz, and some unevenness above 7kHz, but the result is very impressive overall, helped because the main horn, running 800Hz to 10kHz here, avoids the usual 2kHz-to-4kHz presence-zone discontinuity.

Also, it seems that Paul Messenger knows a bit about the Lansing legacy.

[scott fitlin]

Mike, I agree that a gently falling response sounds best, at least to me. I have heard various theories over the years that an ideal response falls at 2 or 3dB per octave above 2kHz. or some such.



This probably all relates also to our earlier discussion of diaphragm resonances. I once asked Dr. Bruce Edgar about all this, and he said "Flat response would sound fine if it was clean." Problem is that most drivers do not reproduce the top octave cleanly, without artifacts that are grating to the ear.
OK, days work is done, now talk talk!

Years ago, we used to have people come in a noise the room, walk it with a mic, and use the RTA.

Flat, as in a flat line, everything@0db was not what they did. More like the gradually downward sloping straight line, the graudual slope beginning around 2K as has already been mentioned! We also use a slight rolloff at the very extreme top end.

They called this a big room house curve. Then, after the room was curved, we would spend another hour listening to familiar recordings, and putting the final touches on by ear!

[Ian Mackenzie]

There used to be special threatre room curves and the like however I don't know what they do now with THX.

Back on track with FR, I find the balance of overall response in terms of level of one region relative another crucial to voicing and its lot hard to get right than than tweaking out small dips and peaks.

For example if the 50-250 region is just 1/2 a db down on the 250-1000 region it will effect the tonality of the bass and lower mid. If the 1000-8000 region is down 1/2 or up 1/2 a db it will sound either recessed or forward..Try seeing 1/2 a db on your curves, you probably won't but it will either sound nice or crap......

Small random variations tend to be of little consiquence audibly compared to large regular variations. If I see a small dip or peak I don't loose sleep over it in other words. The area from 1000-3000 however appears more sensitive to variations than some others and is often a source of irritation if it is peaky or rough.

The reality is inexperienced people spend a heap of time equ ing out their home system and often make it worse, although they are convinced they made it better until a friend comes over and says that sound wrong.

Now, early reflections which cause a blurring of the system time response to impulse transient tones are a sigificiant issue in terms of imaging and resolution but you won't see those on a regular Frequency chart. Waveguides are becoming common is small systems, this is because thet are effective in the control early relfections.

If you can't control these early reflections at least make sure they are symmetrical for both left and right loudspeakers. The ear and brain is very good at differentiating variations in the left and right ear and this is why well balanced and set up systems are often referred to as Hi End. This is because the ear/ brain has very little to complain about. The whole response might not be necessarily dead flat but what the brain hear's is the same in both ears.

None of this is rocket science (at least these days) or audio puffery, but is based on research and common good practise.

Ian

[Mike Caldwell]

Hello
Human hearing is at it's most sensitive in the are from about 800hz through the 6000hz area. So a system does not need as much output in those areas for it to sound correct to our brains....in theory.
If I take out the SMAART system to a show I'll give the system a quick check with it and fine tune with my voice using the vocal mic of choice for the given show. Generally I just use the voice through mic and then will tweak a little during sound check and the show. Some guys will bury their heads in screen of their lap top watching the display and forget to listen how things actually sound. Like Scott said you have to spend to time listening.


Mike Caldwell

[boputnam]

Human hearing is at it's most sensitive in the are from about 800hz through the 6000hz area. So a system does not need as much output in those areas for it to sound correct to our brains.......and for best intelligibility.

Great post, Mike.

Once the house EQ is Smaart'ed, and the gain structure is right, there is generally very little that is needed of the faders. You can bring out the lead vocals at times of increasing band volume just by a (very) slight tweak in the 2kHz to 3.5kHz region. Very subtle changes to EQ in the range you mention have big impacts to it sounding "correctly". These are great "tricks" to keep the SPL from getting away from you. I hate to see even 105 dB anymore... :no:

[boputnam]

Zilch, that curve you posted falls at about the same rate that I am seeing in my room at present...Me too, but not while running Pink noise.

Steve - I run Pink noise and get the response flat as possible (FFT mode, Smaart). That curve Zilch posted is basically the curve I then get on an RTA. There is less energy needed with increasing frequency to sound "correct".

[Mike Caldwell]

For me a live show be it music or spoken word is all about the vocal intelligibility, if you achieve that everything seems to fall into place. Some people think that a podium mic and a lapel mic gig would be easy but when you may have 1500 or more people hanging on every word someone is saying they don't care what the response cure looks like on your lap top! I used my most recent speech only show as an example, earlier this week I did a big welcome home ceremony for a returning Olympic athlete.
Just to make this more off topic than I have already taken it my favorite podium mic is the AKG c535.


Mike Caldwell

[pde2000]

you are all totally wrong (and right). enjoyment of music is so subjective. we remember the experience of a piece of music bringing tears to our eyes (and the best is live, accoustic preferably) and want to recreate the same every time we put needle to groove. no chance. ive heard extremely expensive stuff and been left cold. one listening room at the penta (uk show) was for cheap little 2 way boxes (audax drivers $100pair) and the front end was an oracle thru krell, but the music was susan vega - awesome, best room in the show. maybe there was a magician behind the curtains casting a spell. i thought for a while that the mains electricity was affecting my hifi because sometimes it gave me no pleasure. then i went to stay in a forest for a few weeks with no mod cons and lots of fresh air and silence (original version of a floatation tank) and when i got back the magic was back. All, and i mean all, hifi reviewers are full of fertilizer and probably take a bung for their opinions to be favourable.

the actual pleasure is in your head. i dont take drugs myself but i understand they can make all the difference (i mean beer of course).

You know Walker from accoustical (Quad) never listened to any of his designs, except sweeps etc., and now the esl57 and quadII are reference. he built all his stuff purely on technical measurement and got a high degree of accuracy which translated to near perfection in music for some customers. But if you compare the esl57 to the esl63 tho, the later is technically superior yet gets no praise.

when you think you know, you dont.

[JBL 4645]

Seems like fairly common issue regarding “it sounds too bright” now what is the common frequency that will have ether one of us grumbling and moaning.

I seem to recall it’s within (2 KHz to 4 or 5 KHz) can’t remember what thread I read this on?

Now, what are the easiest tones that normal hearing can pick out, in the higher frequency register?

KHz 1 2 3 4 5 6 7 8 9 (10 11 12 13 14 15 16 there about)

Also there are tones that seem so easy to hear they sound higher in level over the smaller tones above it because there’s 4 or 8 KHz blocking what is ahead of it, like 10 KHz or maybe 16 KHz.

Would it not be easier for total flat response in the high range to iron out all the peaks so its virtually flat and easier to hear the common tones with less harshness and the more uncommon exclusive tones above 10KHz to 16 KHz or tiny fraction higher thou that would be wishful.:)

[1audiohack]

Hi Ashly;

Score another one for Bell Labs, the curves you are looking for were created by Harvey Fletcher and W.A Munson. In 1933 they did an equal loudness study and created the Fletcher/Munson curve chart and released a paper on it in 1937.

I don't have a copy of the chart handy but if you go here, lindos.co.uk and open the articals tab, toward the bottom is an artical called Equal-Loudness Contours.

Cheers.

[boputnam]

...the curves you are looking for were created by Harvey Fletcher and W.A Munson. In 1933 they did an equal loudness study and created the Fletcher/Munson curve chart and released a paper on it in 1937. Here it is, with the supplemental info from 2003 study. You can see the abruptly increased sensitivity between 2kHz and 5kHz.

[JBL 4645]

Hi Ashly;

Score another one for Bell Labs, the curves you are looking for were created by Harvey Fletcher and W.A Munson. In 1933 they did an equal loudness study and created the Fletcher/Munson curve chart and released a paper on it in 1937.

I don't have a copy of the chart handy but if you go here, lindos.co.uk and open the articals tab, toward the bottom is an artical called Equal-Loudness Contours.

Cheers.

Yeah I see bop has posted below or above this post. :D

Is there a winder stretched out version of the same graph, or is that it?

Okay the way I see it is the red has bit of loudness in or around 1 KHz peak.

The Blue has it softened down reduced followed with some gain reduction around 4 to 9 then slowly rising though the rest of the tones that would otherwise appear very faint due to wavelength and therefore the need to be bit louder while remain tones behind it are reduced because they are easy to hear or would show up on an RTA/SPL db meter.

I was thinking about this a few weeks back because some high frequency tones in films modern Dolby films tend to have this, exclusive high pitched tone that would appear faint (but kinder there).

I don’t have enough bands to deal with all the tones in the high range and this would mess-up the high frequency transparency from LCR to surrounds because the tonal characteristic would change.

Still its worth another go at it. Also I need to boast the amplifier power up gently for the HF for the Control 5.

I don’t like the 1/3 TrueRTA too much. It dances around too much and I’ve tried all three settings to slow it down.

Guess I could run it with (Peak Hold) just have to remain quiet when doing it, the slightest sound and it bumps up a few db!

Still I’d like specification sheet for the HF drivers for the control 5 not the pdf manual it doesn’t show what I need to know, the frequency response for the driver as for sensitivity and ohm/power handing.

[herki the cat]

Flat response with titanium-diaphragm compression drivers is too "bright" for me, With aluminum, damped, and mylar diaphragms, I find that I prefer flat.

herki;
I :dont-know Mylar is a tough durable material with a slight price to pay in that it presents a tizzy artifact around 6,000 Hz which is obvious in certant Electrostatic speakers. Perhaps compression drivers have better damping to control mylar behavior.

Phenolic membranes win every time for damping. Don't be surprised that poorly damped soft titanium diaphragm domes present intensified high frequency artifacts in the spectrum above the mass breakup point activated in circumferential stretching modes at the voice coil junction to the surround suspension.

Note: the 2440 wins with an excellent "half roll' surround. LE-175 & LE-85 & 2420 with identical aluminum diaphragms with tangential surrounds are also magnificent especially with flux density in the 20,000 gauss range.

Intensified high frequency loudness has to do with that fact that perceived loudness is a function of both sound pressure level as well "duration of the sound" which a presents in poorly damped membranes or oscillating bodies in the same manner that a good auditorium intensifies sound duration, especially at the lower frequencies where the true warmth of music prevails.

Conversely Putting the magnificent Philadelphia Orchestra in a cow pasture produces a very anemic sound compared to the beautiful loudness of the concert hall auditorium extended reverberation sounds.

[1audiohack]

Hi Ashly;


Is there a winder stretched out version of the same graph, or is that it?

Don't get impatient with me, sometimes I have a hard time following you. Do you mean is there a easier to view graph? Or are you looking for one with extended bandwidth? In all my books that is the only aspect ratio I have ever seen.

Did you by chance read the page I linked you to? If not I would read it.

Don't let an RTA drive you crazy, it's a useful but very limited tool.

[JBL 4645]

Hi Ashly;


Don't get impatient with me, sometimes I have a hard time following you. Do you mean is there a easier to view graph? Or are you looking for one with extended bandwidth? In all my books that is the only aspect ratio I have ever seen.

Did you by chance read the page I linked you to? If not I would read it.

Don't let an RTA drive you crazy, it's a useful but very limited tool.

I’m grandly getting to grips with its understand. I was using this program for the 10th or 14th time.

Equal loudness contours and audiometry - Hearing test on-line
http://www.phys.unsw.edu.au/jw/hearing.html

Limited by effective yes, ;) otherwise I’d be shooting the dark with the EQ.

I'd back up and read it though. I have other things ping-ponging around, you know (information).


Edit: reading up on it now. http://www.lindos.co.uk/cgi-bin/FlexiData.cgi?SOURCE=Articles&VIEW=full&id=17

[herki the cat]

Measurements don't tell the whole story.

herki:
Well, scotty, do you know why "Measurements don't tell the whole story?"

Most of the time "measurements are being made on the wrong thing with incorrect test equipment. Serious distortion occurs in speakers due to spurious uncontrolled ringing of diaphragm elements & related components requiring controlled damping.


"the Problem is that most drivers do not reproduce the top octave cleanly without artifacts that are grating to the ear. Flat frequency responce is fine providing there is no distortion." I have to agree with Dr. Bruce Edgar concerning frequency response measurements.

Still, I do not see anyone talking about measurements with "Tone Burst Technology" which really can expose the most subtle spurious ringing artifacts. General Radio Inc produced an excellent Tone Burst Generator 60 years ago which we used extensively in RCA Camden to see defects you could not identify with conventional frequency response or distortion measurements.

[1audiohack]

herki:

Most of the time "measurements are being made on the wrong thing with incorrect test equipment.

Still, I do not see anyone talking about measurements with "Tone Burst Technology" which really can expose the most subtle spurious ringing artifacts. General Radio Inc produced an excellent Tone Burst Generator 60 years ago which we used extensively in RCA Camden to see defects you could not identify with conventional frequency response or distortion measurements.

It has been said "We measure what we know how to measure, because we know how." Also, "That in order to properly measure something you must know everything there is to know about it." I thought well, if you know all there is to know about something, you would not need to measure it right? It sounded silly to me until I really thought about it. So I could to some extent agree to your statement.

Would you mind elaborating on the "Tone Burst" test process a bit? How did the generator work? How did you colllect, view and interpret the data?

Thank you,
Barry.

[herki the cat]

if it sounds too bright”what is the frequency that will have us grumbling and moaning.it’s within (2 KHz to 4 or 5 KHz) what are the tones that normal hearing can percieve ?... 1 2 3 4 5 6 7 8 9 (10 11 12 13 14 15 16 KHz ? tones that sound higher in level than smaller tones because 4 or 8 KHz blocks what is ahead like 10 KHz or maybe 16 KHz. Would it be easier for total flat response in the high range to iron out all the peaks so its virtually flat and easier to hear the common tones with less harshness and :blah: :blah: .:)

Not at all, it dose not works like that...but it goes like this:

1) Each of your ear cannels is aprox' one or two centimeters long formining a resonant cavity like an organ pipe in church which yields a 15 db increase in hearng sensitivity around 1500 to 2000 Hz in a narrow band which can be extremely loud for any person with hearing impairment because the natural
hearing AGC, aka "automatic volume control" of a young person no longer functions if you have any hearing nerve damage. Sounds from clanking china in the kitchen & loud speaking persons near you can be devastating and so on into the HI FI Mess.

2)...If you have any hearing imparement due to exposure to very loud sounds like gun fire, excessive rock & roll music, loud HI FI, illness history you may have hearing nerve damage known as "Presbycusis" which will pesent loss of hearing the higher frequencies above 1000 Hz progressively worse with ascending scale of higher frequencies. This can happen at any age; you need not be 75 years old to experience this tragic situation.

3)...With this you will experience "masking influence" by low frequency noises like street traffic or trucks, motor cycles etc, and especially loud speaking females at your side, that seem to drown out your hearing ability . Listening to a speaking person in a small room with hard plaster walls or a kicthen tiled floor that rings like hell in the voice fundamentals spectrum around 200 to 300 Hz will present extremely poor inteligibilty.
4)..Presbycusis is gradual hearing losshttp://images.intellitxt.com/ast/adTypes/2_bing.gif (http://www.lifescript.com/Health/A-Z/Conditions_A-Z/Conditions/P/Presbycusis.aspx?gclid=CMCmh9DusqECFUFM5QodSwPJAA&trans=1&du=1Active&ef_id=1350:3:s_efdc7029b8047041d510bf7d81ff6d35_34 91485591:S90hFNBbrmQAADIqD9kAAADA:20100502065204#) in both ears that commonly occurs as people age. Nearly half of all people at any age exposed to loud sounds. Older people naturally have this form of gradual hearing loss which can be mild, moderate, or severe. Presbycusis usually involves permanent hearing loss sometimes referred to as nerve deafnesshttp://images.intellitxt.com/ast/adTypes/2_bing.gif (http://www.lifescript.com/Health/A-Z/Conditions_A-Z/Conditions/P/Presbycusis.aspx?gclid=CMCmh9DusqECFUFM5QodSwPJAA&trans=1&du=1Active&ef_id=1350:3:s_efdc7029b8047041d510bf7d81ff6d35_34 91485591:S90hFNBbrmQAADIqD9kAAADA:20100502065204#) . Certain medical problems can also lead to hearing loss. If you suspect you have presbycusis, contact your doctor.
The Ear
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please explore this link www.nucleusinc.com (http://www.nucleusinc.com/)

There are several causes of presbycusis including:

Gradual degeneration of the eardrum or delicate structures within the inner ear (hair cells) due to age
Changes in the hearing nerve pathways in the ear leading to the brain
Repeated exposure to loud sounds, music, or equipment which can damage the fragile hair cells within the inner ear involved in hearing
Hereditary or genetic influences
Risk Factors: You can explore this subject further in the Wikipedia free dictionary under "presbycusis"

[JBL 4645]

herki

Yes I see what you mean by cavity.:) If hum the sound is less. If I hum again and place my fingers over my ears the humming is louder because its being produced in-head or cavity, no?

If I may an Arhhh sound where my mouth is open the tone is loud without placing my, fingers on my ears. If I place my fingers on my ears the tone is decreased in level.

Weird LOL

It’s hard for me to maintain a smooth whistle blowing sound/tone 1 KHz without it fluttering and its pitch waving up and down…Okay just managed to hold a steady tone and there’s tiny difference with fingers over ears and without.

Higher 2 KHz the tone is decreased with fingers over ears and without its louder!

I just did this out of the blue rather than using sound generated tones coming from a loudspeaker. In the real world these tones would be everywhere there are no headphones to ware the tones are around us.

I might try this again with sound generated sine wave with fingers pressing on the ear.

http://en.wikipedia.org/wiki/Ear

You know what I find distracting its wearing ear plugs while you are walking down the road! You just hear this low TUMP! THUMP! THUMP! Sound of your footsteps! Now that is creepy!

Basically there’s no way to win over loud traffic noise, unless you walk very, very slowly! At normal walking pace it’s THUMP! THUMP! THUMP! Not sure how loud that is if measured with an SPL db or RTA but sounds way over 80db.

The legs act as sound transmission though the body right up the ears or head/cavity. Wow this whole thing now is making my skin crawl.:(:D

[herki the cat]

herki......
item #1)Yes I see what you mean by cavity.:) If i hum the sound is less. If I hum again and place my fingers over my ears the humming is louder because its being produced in-head or cavity, no?
Item #2)You know what I find distracting its wearing ear plugs while you are walking down the road! You just hear this low THUMP! THUMP! THUMP! Sound of your footsteps! Now that is creepy!
Item #3)Basically there’s no way to win over loud traffic noise, unless you walk very, very slowly! At normal walking pace it’s THUMP! THUMP! THUMP! Not sure how loud that is if measured with an SPL db or RTA but sounds way over 80db.

Item #4...The legs act as sound transmission through the body right up the ears or head/cavity. Wow this whole thing now is making my skin crawl.:(:D

herki:
Item#1) Yep! The open ear canal normally acts like a Little tiny one note pipe organ resonating like a "church bell's continued ringing sound", adding duration to sounds around 1500 Hz, thereby adding some 15 db of perceived loudness boost in the 1500 Hz spectrum; this is the spectrum area where we hear best, and finger over the ear closing up the cavity magnifies this action severely just like the cavity behind the woofer in a 1947 klipsch horn.

Item#2) Now when closed up by ear plugs the ear canal becomes a high Q sealed cavity like a speaker enclosure at resonance with additional strong hang-over loudness stimulus. Try chewing a cracker or some crunchy celery while wearing ear plugs or finger over the ear. WOW!!

Item#3) You can get kilo-buck expensive hearing aids with electronic noise canceling performance.... or a $29.00 "Phillips inc" very comfortable over the ear high quality sounding head phone set with good electronic noise canceling features ...On Line-sourced... great around traffic noise , police cars, ambulance & fire trucks etc, and good for music.

Item#4) Its all natural ...comes with the territory, but there is no need to suffer any further....Cheers

[herki the cat]

[QUOTE=1audiohack;286990]Would you mind elaborating on the "Tone Burst" test process a bit? How did the generator work? How did you collect, view and interpret the data? Barry.[/QUOTE

herki:
Tone burst technology examines "loud speaker" spurious response, ringing hang-over, which persists after the applied audio energy to the speaker under test has turned off. This test system requires a good professional microphone with excellent transient response free of the defects being explored in the subject "loud speaker under test."

Continuous on-off... eight-sign-wave duration periods of audio signal, swept from 20 Hz to 20,000 Hz, are applied to the speaker under test to observe for any unwanted signal ringing hang-over activity during the signal-off periods which may persist only milli-seconds after the signal turn off event.

Acceptable speaker ringing hang-over performance permits only one tenth of one sign wave period at any frequency from 20 to 20,000 Hz.

The "Tone burst stimulus audio signal comes from a conventional manual slow sweep, sine wave, 20 to 20,000 Hz audio signal generator via a tone burst "on-off" switching signal conditioning system feeding a high quality power amplifier.

[1audiohack]

Hi Herki;

Thats pretty much exactly as I remember the process. I guess if I had thought out my question better I really wonder how the generator worked. If it wasn't capable of switching on and off at the zero volt point of the sinewave it would really be approaching an impulse which by definition is infinite in frequency and occuring in zero time. What I don't know is how you do it without the switching causing it's own transient as that would drive any loudspeaker into nonlinearity.

Please don't think I am trying to trip you up, I really want to know how they accomplished that.

[herki the cat]

Hi Herki; I really wonder how the generator was capable of switching on and off at the zero volt point of the sine wave. What I don't know is how you do it without the switching causing it's own transient that would drive any loudspeaker into non linearity. I am not trying to trip you up, I really want to know how they accomplished that.

herki:
No problem, 1audiohack;287062, I had intended to mention the requirement for precision on-off switching at the Zero axis, but it took a little doing at 3:00 AM to precisely describe the test system text in concise terms to comply with your request.

The General Radio Inc., Tone Burst Generator dose perform the "on -off" switching precisely... stone cold clean, at the Zero Signal cross over point. You can verify this feature looking at the GR Tone Burst Generator output with a 40 Megacycle Scope which does present a perfectly clean on-off function.

This system hardware does not require Rocket Science. This feature is straight forward to accomplish with vacuum tube designs and high voltages to generate plus & minus 300 volts peak to peak audio signals, from which you can derive pretty steep sided square waves cut down to 10 volts peak to peak to perform the switching control function precisely at the zero axis.

Your only problem is to find a Genuine General Radio Inc., Tone Burst Generator or new equivalent. General Radio closed their doors around 1970.

[JBL 4645]

herki:


Item#2) Now when closed up by ear plugs the ear canal becomes a high Q sealed cavity like a speaker enclosure at resonance with additional strong hang-over loudness stimulus. Try chewing a cracker or some crunchy celery while wearing ear plugs or finger over the ear. WOW!!



As for chewing or crunching on crisps or biscuits they tend to make the visual vibrate practically when looking at TV screen the image just vibrates flutters.

[1audiohack]

Hi Herki;

Thanks for taking the time to explain.

I have two measurment systems that will measure several types of distortion by stepping through the frequency range of interest. With one of them if not both I can hear switching transients that I can't see on my scope. I still trust my ears to some extent.;) I am saving my pennies for a quality digital storage scope, that should help me answer that question and few others.

So did you say the tone burst generator you folks used was a square wave generator?

Thanks again,
Barry.

[herki the cat]

Hi Herki;Thanks for explaining. I have two frequency stepping systems & I can hear switching transients not seen on my scope.;) am saving for a digital storage scope. So did you say the tone burst generator you folks used was a square wave generator?Thanks again,Barry.

herki
The General Radio Inc., "Tone Burst Generator" does not function as a square wave generator of the test-stimulus signal. It is not a frequency-stepping system & it functions only as a precision "on-off" switching system employed in the signal path of a manual frequency-swept audio generator permitting the the engineer to dewel on speaker performance areas while engineerng speaker design changes.

The General Radio Tone Burst Generator has a precision "phase-locked clock," counting"eight sine-wave periods" of stimulus-test signal "ON" followed by "eight sine-wave periods" of "zero energy stimulus signal-silence" to present engineering observation of speaker over-shoot ringing aberrations .... these rascals constitute over whelming, long duration, loud sounding trash not observed in any other known measuring technology.

The General Radio System uses the "positive-going" leading edge of the square wave ONLY to prepare the switching circuit to precisely execute the clean "switching-off" event in micro seconds at the zero energy cross over point.

After clocking the "eight sine-wave period of "zero energy stimulus-signal silence" the programmed"negative-going square wave leading edge prepares the switching function of the next "stimulus-test signal "ON" event.

This is a very sophisticated machine originally designed by RCA engineering & manufactured by "Long-Extinct" General Radio inc., sadly, not yet equaled by any popular devices offered by the current industry...digital technology not with-standing.

BTW, This General Radio "Tone Burst Generator" system was the exclusive favorite developement tool of a friendly Camden Rival & Pal, of RCA's Dr. Harry F.Olson, the estimmed RCA Scientist, Dr. Murlan S. Corrinton, inventor of RCA's Microgrove Technology for the 45 RPM 7 inch Disc & the RCA 12 inch Micro Groove LP "45/45" Stereo-Modulation Format, two years before Columbia Records suddenly released the the first production of the the Mono LP Record in the late 1940's, while RCA was preparing the funds for LP Production. (See: Wikipedia "Colombia LP Records" for the story)

[1audiohack]

That's exactly what I was after.

Thank you kindly,
Barry.