Spherical Horn / Kugelwellen - Trichter

[4313B]

Was it charged coupled on the initial release or are the rumours of dealers soldering in Hovlands true? Just a question.

Why would you care? How would knowing further your life goals?

The community seeks answers not questions about sales in mother America.

What community? What answers? Why?

I hope you are not making a pass at the Japanese marketplace.

I have no idea what you mean.



As for the cut and paste above, yeah, we went through that whole discussion at the beginning of Project May.

This aspect of the discussion is around how far you can take up a woofer before audible problems ocurr.

This interests me because I am iconsidering a high senitivity two way system using the 2435 be driver, a horn of some sort and some sort of woofer. Lots of choices.

Well fortunately all you need to do is satisfy yourself. How about a pair of LE14H-4's? Greg likes their slight increase in sensitivity over the older LE14's. He uses them to great effect in the S4600. The LE14H-3's and LE14H-4's are probably the best bet for a 2-way without a subwoofer. I just posted the LE14H-4 in the Transducer Information section.

[Robh3606]

Was it charged coupled on the initial release or are the rumours of dealers soldering in Hovlands true? Just a question.

Yes with Mylars and PP bypass.

The box modes in a big studio-monitor (or JBL K2) box are much harder to control, and to my ear, lend an annoying "droning" quality to the sound, a traditional part of the sound of big vintage loudspeakers. These modes are quite apparent when the drivers are pulled and you put your head in the box - you hear a droning, drumming quality to ambient sounds, and the box stuffing and damping, although reducing its magnitude, adds its own dull, murky quality to the droning sound.

Do your boxes sound like that?? I would think the tuning would be more of an issue with the older vintage designs although some of those boxes are a bit loose.

Rob

[Hoerninger]

To come to the bottom of this thread what about an augmented two-way system?

I remember
JBL's New Maximum Output Midrange/Low Frequency Transducers. (TechNote 24)
which introduces the 2012H and 2020H as speakers with
1. extended power response
2. high efficiency
3. low mass, high resonance
4. low distortion
5. adaptability to horns
6. high reliability,
these are qualities to have an eye on.

When using one of these speakers with a horn 100 Hz to about 1000 Hz you have no boxiness (The back chamber is presumably very small), the cone will behave better than that of a 15 inch one.
It might be that time delays between the mid bass horn and the mid/highs horn are less significant.
The deep bass will be augmented by your choice,the speaker will only be fed up to 100 Hz, surely an advantage.

Regarding the mid/highs horn, a Kugelwellentrichter has a wider dispersion than a tractrix horn as it is shorter. The length influences time delay additionally.

An example with a midbass horn and an augmented bass you can see at volvotreters home page
__________
Peter

[Mr. Widget]

One needs to remember that ones perception of timbre and image quality is as much influenced by the listening room acoustic as by anything else.

Amen!

It's remarkable how tolerant we become of our own listening room's additions and how intolerant we are of others.

We also can become very tolerant of frequency response anomalies in systems... for example when listening to a system in your car, it still sounds acceptable even though the curve will be far from neutral. I have discovered that for fairly minor inaccuracies in frequency response we will automatically "correct" the response in in our brains after a few minutes of listening.

I am not saying that a neutral frequency response is unimportant, but we are quite capable of adapting to a system and finding musical enjoyment despite it's having a colored sound.

I personally believe that the compromises inherent in stretching a 15" drive unit to cover half the audible spectrum are no worse than those involved in adding another crossover point with all it's attendant baggage.

You bring up an interesting point. I'd suggest the correct set of compromises are determined by the individual. For me, I am not happy with the sound of a large woofer being asked to play very high. I prefer the additional time smear and lobing one gets with an additional driver. I don't look for time smear and lobing, but If they are controlled, I find they can be more easily overlooked than the beaming, harmonic distortion, and sonic qualities caused by using a 15" woofer up into the mid range. Once again, it is dealing with compromise.



Widget

[Mr. Widget]

Michael,

Your worship...

Just to amuse me, could you tell me what constitutes the near field in my living room and what the critical distance is? I presume you are in posession of the RT60 figures or are you simply puffing up your colonial chest?

Now come on you two... no need to get personal here.

FWIW: In the research I have done, RT60 measurements in smaller rooms like those we all live in, RT60 measurements are pretty well useless.


Widget

[Mr. Widget]

Peter, sorry for my contributions toward veering off topic. I think it's time we return to your spherical horn discussion.


Widget

[Ian Mackenzie]

The type of horn is often dependant on the lower frequency driver you decide to use and the reasons behind that.

Perhap the penny will drop in a moment if I make it easier for some of you to step outside the JBL square.

Regardless of JBL's marketing direction or commerical decisions there are laws of physics which tell us a lot about the effect of cone size on the cone behaviour.

Every cone driver has a break up point and break up modes beyond a certain frequency. This is well documented and discussed in the above diyaudio thread.

Beyond the breakup frequency the cone no longer operates in piston mode. This means the driver will no longer be an accurate transducer as a pure piston mode driver and it wont sound as good. (this is why woofers that have straight cones sound better)

Some people try and damp the cone or use stiff materials to moderate the break up mode behaviour. The problem does not go away and usually pops up some where else.

There are a few choices.

Do nothing about it if the primary goal is simplicity and the benefits of the larger cone like sensitivity and low frequency output.

Lower the crossover point and use a larger horn. This is where the grey matter comes in regards the style of horn. The lower a horn goes the larger its mouth and axial length.

Ever seen a 500 hz conical horn? Obtaining uniform power response and low distortion and wide bandwidth with a lower horn frequency is not easy.

Use a smaller woofer cone. The smaller cone will have a higher break up modes and will operate in piston mode at higher frequencies. It may not have the same sensitivity or low frequency output.

The smart loudspeaker builder can get around this by using multiple woofers that reperesent a line array at low freqnencies and a point source at higher frequencies. The tailoring the high frequency of each driver progressively you can obtain extended bass response and output while mantaining good sensitivity and low distortion.

The narrower box also has less diffraction issues.

As a result this frees up the contraints on the type of horn.

Big horns have a low waf factor and require a seriously good compression driver for them to work properly.

Dr Geddes an authority on horns maintains (if you can understand his disucssions) that there is not a lot of merit to using a waveguide (at least ) below 1000 hertz.

Looking at it from another angle why make it hard for yourself by accepting you must use a large diameter woofer? I guess people need to impress themselves or the market.

The question of constant power response is a design decision and there is a lot of debate over this point with horns.

But there is no mistake on breakup performance and this underpins IMHO the midrange performance any loudspeaker.

I have discussed one approach above and there are others like using a smaller or multiple samer bass mid drivers and a crossover point between 50-100 hertz and an activr sub below this frequency. This approach has alot of merit because the requirement of the low bass can be dealt in such a manner as to not compromise the rest of the loudspeaker.

Large drivers located lower or near a floor boundary are going to have issues if they are operating in the midrange.

It is interesting to note Bose has sold lots of loudspeakers because of good brand marketing. Des that make them a good loudspeaker. No.

It is also interesting to note that critical comments about the JBL K2 and the E2 focus on what happens below the horn crossover frequency. What happens with the horn is brilliant and that is its strength.

Tad went about it differently and its regarded as a superior loudspeaker..

[Ian Mackenzie]

Yes with Mylars and PP bypass.



Do your boxes sound like that?? I would think the tuning would be more of an issue with the older vintage designs although some of those boxes are a bit loose.

Rob

Rob,

If you check out the links in the Eighteensound web page they have kit designs with box diapgrams that address this problem. The use of non parralell sides and liberal use of damping at the back of the box and the ends helpe mimimise the issue.

[Hoerninger]

This interests me because I am iconsidering a high senitivity two way system using the 2435 be driver, a horn of some sort and some sort of woofer. Lots of choices.

Ian,
are you in the phase of discussing basics or is it the search of a good mid bass / mids driver? I am still looking for a candidate, have not found it yet. (Years ago an AUDAX PR170MO predecessor was a candidate which I used - now out of production, but cone brake ups are apparent.)

Then it is a question of making it concrete, fulfilling your design goals. And that is as always a question of compromises (not meaning faults).

Interested to follow your headway.
___________
Peter

PS:
http://www.audioroundtable.com/PiSpe...ges/13339.html
discussing some JBL and 18Sound 6ND410, which is quite nice

[Earl K]

Hi,

Peter, are you able to post a version of your spreadsheet that opens in MicroSofts' Excel ?

Thanks < Earl

[Hoerninger]

Earl,
wait a bit (a month ), in my vacation I will do it.
Normally there is no Windows at hand for me.
__________
Peter

[Earl K]

Hi

Earl, wait a bit (a month ), in my vacation I will do it.
Normally there is no Windows at hand for me.

- Okay, I understand the need to wait ( since soon I'll be away on my golfing vacation ) .

- If you're strictly Mac based , how about making it an AppleWorks spreadsheet ? ( many of us still have that software standing by to do something useful ) . Or are you Linux based ?

<>

[4313B]

Tad went about it differently and its regarded as a superior loudspeaker..

Ian, it sounds to me like you have it all figured out and might want to talk to Mr. Widget about getting some TAD transducers. Did you get a chance to hear his system when you visited?

[merlin]

T
This means the driver will no longer be an accurate transducer as a pure piston mode driver and it wont sound as good.

Assuming that the one follows the other is dangerous and ignores all the other variables in speaker design.

In my experience wide baffled designs simply sound more natural and convincing. Narrow baffles sound like good hifi. I'm after music not good hifi. Whether it's to do with the shifting of the baffle step or something else I don't know but I certainly prefer wide baffled loudspeakers by a considerable margin..

[Hoerninger]

Or are you Linux based ?

No (,not yet.)
I am using IBM's OS/2, I grew up with it.
You can still buy it as eComStation, it is a niche product.

[I am using two screens with 1600 x 1200 each. It is useful to look at PDFs with 1600% resolution. Regarding earlier postings in this forum I will give a an additional remark soon ( ), at least for long term readers.- Hello Mr.Widget!]
___________
Peter