Visit to Audiophile Bill to hear his horns project

[Audiophile Bill]

The quality of work is immense, just wow ...!

Thank you, Al, for the kind comments.

 

[spiritofmusic]

Thanks Marc. Yes he was surprised how badly I was bitten by the bug. At one point I was sending him images of bowls and hollow forms on a daily basis during lockdown for critique and teaching. I made all sorts of mad things mainly for practice.

Yes as you correctly say - he is made like they aren’t made now. Seriously puts me to shame. He turns 89 in the autumn and he cycles minimum 15km per day at his age. He goes to the gym 4 days per week. He has been vegetarian for 20 years, which he seems to think helps his immunity etc. I would leave his workshop after a 10 hour day literally desperate for bed. He went off to play table tennis with his great grand children.

Some madness below - good for practice as much harder than horns.
View attachment 67495

Scary stuff...your man obviously really believes in living life. Lord knows what he thinks of lazy audiophiles.

 

[Audiophile Bill]

Scary stuff...your man obviously really believes in living life. Lord knows what he thinks of lazy audiophiles.

He is very pro getting moving and not sitting about. He gets very ratty with his great grand kids for playing PlayStation all the time lol.

He is more of view of get them outside playing in the garden and doing stuff.

 

[spiritofmusic]

Top man. WBF not for him, then Lol.

 

[Rob181]

He is more of view of get them outside playing in the garden and doing stuff.

I'm with him.

What a GREAT build & no doubt the best thread on WBF currently. These are speakers I want to listen to & love the base driver setup.

 

[wisnon]

looking good Bill. Can you post more comprehensive pics please.

 

[Ron Resnick]

From the photos, Bill, the wood-working craftsmanship and the beauty of the wood itself are astonishing.

 

[kodomo]

Bill, congratulations on your endeavour, nothing matches making your own speakers in my experience. I have done many and still enjoy one as my main system.

There was a lot of talk about 4001 and 4003 differences. One of the main differences between TAD TD-4001 and TD-4003 is the throat size. TD-4001 has 49.2mm (2") throat whereas the TD-4003 has 39mm (1.5"). They both have 5 slits and afaik the same voice coil and diaphragm.

Smaller throat is definitely better for higher extension but I am a believer in adding upper mid and tweeter channels on top to get even dispersion with 2" compression drivers. This is a harder road for the diy enthusiast. A 2" driver may play up to 20khz but throat size creates problems and these are not possible to get rid of as they happen because of physical dimensions of the throat and its relation to wavelength reproduced.

So, with 2" cd I prefer to add more channels. This brings other problems like crossovers and most of the people are scared to hear even the word crossover. If you can successfully implement one they are not a problem but it is not as easy as getting a horn and strapping a cd behind it. If I had used 4003, I may have reduced one channel, the upper mid and directly used a suitable tweeter. The only problem then would be the matching of the dispersion in between those two.

As I am in the process of rolling out a very different approach, I wonder how horn enthusiasts will react to that solution

 

[christensenleif@msn.com]

correction:
4001 and 4003 diaphragms are not the same
neither are the vc´s
I actually have 4003 and 2002, which replaced 4001 and 2001

 

[kodomo]

correction:
4001 and 4003 diaphragms are not the same
neither are the vc´s
I actually have 4003 and 2002, which replaced 4001 and 2001

I never had the 4003 only the 4001 but just have the TAD catalog. Their sizes and materials are the same, so I assumed they were the same. Voice coils are 101mm and the be diaphragms are also 100mm for both. What is the difference in between them?

 

[christensenleif@msn.com]

4001 is Alnico
4003 is Neodym
the vc´s I´m not sure
the dia on 4003 have different and softer suspension and also connection points

 

[bonzo75]

Bill, congratulations on your endeavour, nothing matches making your own speakers in my experience. I have done many and still enjoy one as my main system.

There was a lot of talk about 4001 and 4003 differences. One of the main differences between TAD TD-4001 and TD-4003 is the throat size. TD-4001 has 49.2mm (2") throat whereas the TD-4003 has 39mm (1.5"). They both have 5 slits and afaik the same voice coil and diaphragm.

Smaller throat is definitely better for higher extension but I am a believer in adding upper mid and tweeter channels on top to get even dispersion with 2" compression drivers. This is a harder road for the diy enthusiast. A 2" driver may play up to 20khz but throat size creates problems and these are not possible to get rid of as they happen because of physical dimensions of the throat and its relation to wavelength reproduced.

So, with 2" cd I prefer to add more channels. This brings other problems like crossovers and most of the people are scared to hear even the word crossover. If you can successfully implement one they are not a problem but it is not as easy as getting a horn and strapping a cd behind it. If I had used 4003, I may have reduced one channel, the upper mid and directly used a suitable tweeter. The only problem then would be the matching of the dispersion in between those two.

As I am in the process of rolling out a very different approach, I wonder how horn enthusiasts will react to that solution

There is much more difference between 4001 and 4003
- As Leif said difference in voice coil and suspension
- Neodymium was used in 4002 and 4003
- Phase plugs are 5 in both, but changes were made to shape and material for 4003
- Direct speaker wire connection to the diaphragm


Regarding number of channels, the people with the most experience I chatted with were all for minimising number of channels where possible. Bill is right with his two way as the AER does not require a tweeter. The TAD 4003 might not, but one can always add a tweeter or a smaller compression driver like Leif has, or like with the Universum, and see if they prefer it. There is a very interesting journey by a guy named Murat who went all the way up to 8-way and came back down to 2 or 3. His is probably the best system that I will not get to hear now. Bass sub can be added actively below, as it does not reduce the responsiveness of the crossover.

Matching dispersion between the mid and upper driver is not an issue if you use a smaller compression driver on top, like Leif or Universum has done. But I probably hear the incoherence in Vox Olympian because he has used a Radial for mids using the Vitavox S2, a narrow trumpet like horn above that with TAD 2002, and a bullet TAD tweeter above that. If not for the gold plating, one would hear these disparities. And a one woofer midbass because many mistakes counter cancel each other, and there is always the colour of Kondo to sugarcoat over the errors.

 

[kodomo]

There is much more difference between 4001 and 4003
- As Leif said difference in voice coil and suspension
- Neodymium was used in 4002 and 4003
- Phase plugs are 5 in both, but changes were made to shape and material for 4003
- Direct speaker wire connection to the diaphragm


Regarding number of channels, the people with the most experience I chatted with were all for minimising number of channels where possible. Bill is right with his two way as the AER does not require a tweeter. The TAD 4003 might not, but one can always add a tweeter or a smaller compression driver like Leif has, or like with the Universum, and see if they prefer it. There is a very interesting journey by a guy named Murat who went all the way up to 8-way and came back down to 2 or 3. His is probably the best system that I will not get to hear now. Bass sub can be added actively below, as it does not reduce the responsiveness of the crossover.

Matching dispersion between the mid and upper driver is not an issue if you use a smaller compression driver on top, like Leif or Universum has done. But I probably hear the incoherence in Vox Olympian because he has used a Radial for mids using the Vitavox S2, a narrow trumpet like horn above that with TAD 2002, and a bullet TAD tweeter above that. If not for the gold plating, it is a total disaster. And a one woofer midbass because many mistakes counter cancel each other, and there is always the colour of Kondo to sugarcoat over the errors.

The first thing is to set goals and then you can try and reach them. For what I wanted to do, compression drivers and horns, I could not do it with less channels without missing my goals. Therefore above my midbass, I have a 2" cd and a horn, a 1" cd and a horn and then a tweeter.

For Murat, as far as I followed his journey he did not spend enough time on refinement, and kept on changing and trying more stuff. I hope he has achieved what he wanted to do. Everybody has a way of working but that is not how I prefer to work.

 

[pjwd]

Bill, what attention to detail , it is very impressive.

I am very interested in your bass unit and how it measures - hopefully one day you will be able to reveal that

Just out of interest did you use ripole math or linkwitz calcs to get to your final position or base it on pass design and do prototypes and measuring

understand if you want to hang on to IP

Cheers

Phil

 

[kodomo]

4001 is Alnico
4003 is Neodym
the vc´s I´m not sure
the dia on 4003 have different and softer suspension and also connection points

I just assumed as the catalog states that both have the same size voice coils and same size and material diaphragms. So the diaphragm is the same but surround has changed. I thought they only changed the magnet to neodymium for higher flux density, made the direct connection to diaphragm, some very minor changes to slit design and a narrower throat. I did not know about a new voice coil or a change in diaphragm design.

 

[christensenleif@msn.com]

I think the softer and different suspension is partly cause of better behaviour in the higher frequencies

 

[christoph]

I am very interested in your bass unit and how it measures - hopefully one day you will be able to reveal that

Just out of interest did you use ripole math or linkwitz calcs to get to your final position or base it on pass design and do prototypes and measuring

I am also very interested in your bass solution?
It does play up to 200 Hz if I got this right?
Why so high up? Isn't the AER capable to play a LOT lower?

 

[christensenleif@msn.com]

a friend had the AER 3 in a BD horn to 150

 

[christoph]

a friend had the AER 3 in a BD horn to 150

In the Pnoe, the AER runs full range to around (below?) 40 Hz iIrc so I though at least 80 Hz should be feasible without horn loading

 

[Audiophile Bill]

I am also very interested in your bass solution?
It does play up to 200 Hz if I got this right?
Why so high up? Isn't the AER capable to play a LOT lower?

Hi Chris,

Thanks for the question and they are very pertinent. My response is below:

>> Yes the AER and Lowthers and various other full range 8” drivers will indeed extend to 100hz. In order to faithfully get to 100hz in the horn, the physics is against us. As the horn fc gets lower and lower the horn size including mouth circumference go up a lot. 100hz fc in the Tractrix form equates to circa 1 metre diameter! Of course would have been possible to have a 1 metre horn physically on top of my module although it would look very aesthetically unbalanced and a quite odd. But importantly a horn is a limited bandwidth device in terms of the acoustic loading (and consequent spl gain) you get from employing it. This is the primary reason that many all out assault attempts in the horn world end up 5 way (sometimes even more). The problem is exacerbated more when you start looking into acoustic loading of the driver from the fc point - I can tell you that in my big multi-way design using compression drivers, one can’t load next to the fc smoothly in any area really above the mid bass. The net effect then is one needing even larger horn to accommodate for the crossover point - for example if you had a midrange horn with compression driver that you wanted for 500-1.5k, then a 500fc horn will not have you covered it you wish for loading at 500hz. Hope that makes sense

>> Sonically I tested horns with bigger diameters to allow (2 way) crossover points down to 140hz but the compromise was too much of the delicious top end of the AER gone, which is honestly its r’aison d’etre. Finally, one of my key design criteria for this speaker was to develop something with loads of weight in the mid/upper bass. My view based on listening was that my 4 x 15” bass solution was able to provide that weight and fullness but also the speed. Think of it like an anchor that underpins the entire sonic picture without which one moves to the more skeletal / thread bare type sound. This is obviously personal but it is my taste and view of how I wish to convey the music.

>> Finally since the anchoring of the sound on my design in the mid/upper bass comes from the bass module - having that actively driven also helps me because I get more drive and no horn attenuation needed because I am in control of gain.

Hope this makes sense