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 !?

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.

[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....

[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! 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! 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! 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)

[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