TAD TH4001 clone project

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#93
I have read that the TAD horns are specifically designed for the TAD compression drivers -- something along the lines of the horn geometry compensates for some response anamolies of the TAD drivers.... but i can not recall the specifics...

does anyone know more on this topic specifically?
 
#94
Are you referring to this post from Bruce Edgar?

Posted by Bruce Edgar (M) on April 19, 2011 at 09:57:04
In Reply to: The 4001 has too many anomalies in the highest frequencies posted by rickmcinnis on April 18, 2011 at 08:54:36:

I have been puzzling over the 4001's response anolmalies since the late 90's when I was using them in my Titans. I first used the 2001 driver which had some nice sonic qualities, but it was dying at 500Hz. I then tried the 4001 which had much better response at 500 but had totally different imaging characteristics. The 2001 had very nice depth of image, but the 4001 had no depth and an "in your face" sound. I used the 4001 because my sponsor(a Chinese Doctor) liked it, but most of my US customers didn't. Some of the latter told me that they weren't coming back to my CES room ever again.

Another US customer wanted me to use a JBL 2440 in a Titan. I was pleasantly surprised that I had depth of image again. At that point I changed over to JBL's for the Titan Horn. Eventually I settled on the JBL 2441 as my standard mid range compression driver. But in the back of my mind I still remained puzzled over the difference between the 4001 and all the other compression drivers on my tractrix horns.

Talking to John Eargle, I learned about the evolution of the JBL and TAD drivers. Bart Locanthi designed the early JBL compression drivers, and after he left JBL he designed the TAD drivers. The 2001 sounds the same as the JBL drivers, but the 4001 is a total departure. Eargle could not come up with a good reason for the difference.

Segway to the present. I had been working with Sam Saye and his developement of Be diaphragms with Brush Wellman. Sam used my tractrix horns to evaluate the Be performance. He called me up last year with an interesting observation. He tried out his JBL/Be drivers on a TAD radial horn and was amazed at the loss of detail.

At that point the light bulb went on in my mind. The reason, I believe, for the 4001's overbearing sound was that it was designed for the TAD radial horn. The TAD horn has an even response distribution over its pattern which is unusual. Most radial horns will roll off on their pattern sides. In a control room, the board ops in the front and the engineers/producers in the the back have to hear the same sound, so constant directivity is a plus for monitor speakers. Hang imaging quality.

In order for the radial horn to achieve constant directivity, you have to introduce internal and mouth reflections in the horn. Otherwise the pattern will peak in the middle. So veiling is inherent in this design. Locanthi and TAD designed the 4001 to overcome the veiling problems in the TAD radial horn. So if you put a 4001 on a tractrix horn which has minimal reflections, you hear all the overbearing "in your face" sound with no depth. This overcompensation in the 4001 design leads to it unusual sonic character.

John Wolfe at Classic had switched to Sam's field coil/Be drivers for thier better sound but was still using the TAD radial horn. Sam told me that I had to design a radial tractrix horn for John. So I designed and built a prototype 250Hz tractrix radial horn pair which surprised me at how good it sounded in my system. I tried to do the manufacturing of it for John but it was beyond my physical capabilities because of all the milling of the wood to make it look like the back end of a TAD horn. John now pays me a royalty and he has a woodworker in Michigan to build it. So if you want a tractrix radial horn, go to John at Classic.

As for my system, I'm back with a regular round 300Hz tractrix horn with my field coil/Be JBL drivers. The radial horns did't have the precise imaging that I liked with my round horns. Please note that I still recommend the 350Hz horns for the JBL drivers because the old Al diaphragms have a nasty resonance at 300Hz. The Be diaphragms have a mylar(or similar material) suspension which don't have the resonance problems of the old Al diaphragms.

Right now I waiting for Nick Ferber to finish a set of 80Hz midbass horns with a furniture finish. (Take your time Nick, I'm not pushing you. Ha!) When it is ready, I will reconvene a gathering of the Southern CA DIY Horn Group at my home to hear my latest horn system. Bruce
Click to expand...
 
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#96
4642a said:
THATS IT!


many thanks
i couldn't remember where I had read the account of their experiences...
Click to expand...

I and my many friends to hear the depth and image is very good.
All uses TD4001 and TH4001 and TN-2 and original TAD 2402 loudspeaker. Many of my friends to give up the JBL Changed to the use of TAD.
I also have listened to the TD4001 + round tractrix horn in the Taiwan. Actually I think TD4001 and round tractrix horn are do not match. Sound performance is not my favorite.
 
#97
Okay guys this is interesting 🙂

So : I own a pair of TD4002's and use them with a Kugelwelle horn from Stereolab in Germany ( I think it qualifiers as a tractrix).
Now I did hear what I think was TD2001 drivers in a full size TAD speaker once, but I have not compared the performance directly.
However I find the sound of my system very 'forward' and I love it 🙂

But Bruces description made me wonder:
How do one make the sound of a driver more 'forward' or 'with more depth' ?
Is it down to equalization?
Is it the composition of 2nd harmonics?
What is it?
 
#98
diycoax said:
I also have listened to the TD4001 + round tractrix horn in the Taiwan. Actually I think TD4001 and round tractrix horn are do not match. Sound performance is not my favorite.
Click to expand...

I believe that was the concern/thought presented above, by Dr. Bruce Edgar...


presented again for your convenience 🙂
Talking to John Eargle, I learned about the evolution of the JBL and TAD drivers. Bart Locanthi designed the early JBL compression drivers, and after he left JBL he designed the TAD drivers. The 2001 sounds the same as the JBL drivers, but the 4001 is a total departure. Eargle could not come up with a good reason for the difference.

Segway to the present. I had been working with Sam Saye and his developement of Be diaphragms with Brush Wellman. Sam used my tractrix horns to evaluate the Be performance. He called me up last year with an interesting observation. He tried out his JBL/Be drivers on a TAD radial horn and was amazed at the loss of detail.

At that point the light bulb went on in my mind. The reason, I believe, for the 4001's overbearing sound was that it was designed for the TAD radial horn. The TAD horn has an even response distribution over its pattern which is unusual. Most radial horns will roll off on their pattern sides. In a control room, the board ops in the front and the engineers/producers in the the back have to hear the same sound, so constant directivity is a plus for monitor speakers. Hang imaging quality.

In order for the radial horn to achieve constant directivity, you have to introduce internal and mouth reflections in the horn. Otherwise the pattern will peak in the middle. So veiling is inherent in this design. Locanthi and TAD designed the 4001 to overcome the veiling problems in the TAD radial horn. So if you put a 4001 on a tractrix horn which has minimal reflections, you hear all the overbearing "in your face" sound with no depth. This overcompensation in the 4001 design leads to it unusual sonic character.
Click to expand...
 
#99
The Mini Horn project...

Mini horn is designed for small space and large momentum performance. Mini horn can be the main speakers, surround speakers or center speaker.

Two way bass reflex.
Bass: 6.5 inch woofer with Neodymium Magnet.
Tweeter: 1 inch exit compression driver with Neodymium Magnet.
Horn: IWT Mini Horn
Spread angle: 120 degrees horizontal, 45 degrees vertical.
Impedance: 8Ω
Frequency response: 45Hz ~ 22KHz
Power Handling: 150 Watts
Efficiency: 92dB
Crossover Frequency: 1.8KHz
Size: 200 (W) x 280 (H) x 300 (D) mm
Weight: 8kg / each

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


Adapters for mini horn.
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Adapters of black sand painting.
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Cabinet for mini horn.
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5.1 Mini horn and mini horn center for Home Cinema.
An externally hosted image should be here but it was not working when we last tested it.
 
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