Visit to Audiophile Bill to hear his horns project

[microstrip]

(...) The best and most comprehensive driver shootout I know off has been done by Leif and his friends in Norway, and they have been systematically been through JBL, Altec, TAD, ALE 7550 DE, Radian, over the last decade, both measuring and listening, and 4 of them ended up with TAD 4003. (...)

Are these comments and measurements accessible in any audio forum or publication?

 

[spiritofmusic]

Big congrats to you Bill, not just for the stellar product you have created but also for the path you have assiduously pursued. Not many will appreciate the extent of R&D you have made, diving deep into the theories of horn speaker design whilst simultaneously developing your woodworking skills to execute. All of this was done in tandem with a demanding career and young family. The finished product you have developed really is top notch and I wish you every success with these heirloom quality speakers!

I believe Ked is frantically checking his lineage to see if there's any family connection...

 

[bonzo75]

Are these comments and measurements accessible in any audio forum or publication?

You will have to read 350 pages on the Nordic forum though using Google translate. I did, but that is only because after visiting Leif and interacting with the others, I realized there would be something to learn and had context and knew the background and calibre of the people. But generally that's the summary, 4 of them have ended up with TAD 4003 and dual FLH, after visiting Leif I ended up buying TAD 4003 (never used stock) and dual FLH has been my favorite design for 4 years or so now.

I don't think it is particularly useful unless you know the sound characteristics of beryllium drivers like Radian and TAD vs non beryllium like Altec. My videos all over the place bring this characteristic out through videos, and I will have them together in my next write up. Some of Tang's videos show the positives of the TAD mids/highs pretty well. If you put on headphones suspending disbelief against videos, you will get the contrast.

A couple of AER videos bring out their highs well, though they have to be heard in person with Mayer 46 and red sparrow to appreciate the full range

 

[microstrip]

You will have to read 350 pages on the Nordic forum though using Google translate. I did, but that is only because after visiting Leif and interacting with the others, I realized there would be something to learn and had context and knew the background and calibre of the people. But generally that's the summary, 4 of them have ended up with TAD 4003 and dual FLH, after visiting Leif I ended up buying TAD 4003 (never used stock) and dual FLH has been my favorite design for 4 years or so now.

I don't think it is particularly useful unless you know the sound characteristics of beryllium drivers like Radian and TAD vs non beryllium like Altec. My videos all over the place bring this characteristic out through videos, and I will have them together in my next write up. Some of Tang's videos show the positives of the TAD mids/highs pretty well. If you put on headphones suspending disbelief against videos, you will get the contrast.

A couple of AER videos bring out their highs well, though they have to be heard in person with Mayer 46 and red sparrow to appreciate the full range

Thanks. Isn't the TAD 4003 unobtainium? Did they consider the TAD 4001?

 

[bonzo75]

Thanks. Isn't the TAD 4003 unobtainium? Did they consider the TAD 4001?

Yes 4003 is tough to source but hey this is a collector's forum. Leif owned 4001 before. TAD 4001 vs 4003 will give you many comments online, including from one of the main guys Mr widget on Lansing heritage forum (though I don't know him personally how he listens etc, he is respected there). But crux of it was that 4001 was extended by adding peak resonances and needs some work in the cross over to smooth that, while 4003 was Bart Locanthi (the engineer's) best work to iron out those issues and was linear to 18khz. 4001 can be used in the same design though. Bruce Edgar has this theory that 4001 works best in TAD radial horns else sounds bright and forward, but I don't know about that. Jdza also has multiple drivers and uses 4003. I am fine with all of these as they all roll over at similar points - Altec, JBL, TAD, Radian... And work with dual FLH. So you could rotate them like you rotate valves in the same design, with minimal adjustment to the cross over. With AER you have to look at lower cross over, running most of it full range

 

[microstrip]

Yes 4003 is tough to source but hey this is a collector's forum. Leif owned 4001 before. TAD 4001 vs 4003 will give you many comments online, including from one of the main guys Mr widget on Lansing heritage forum (though I don't know him personally how he listens etc, he is respected there). But crux of it was that 4001 was extended by adding peak resonances and needs some work in the cross over to smooth that, while 4003 was Bart Locanthi (the engineer's) best work to iron out those issues and was linear to 18khz.(...)

Unfortunately we can only collect thinks we can source. It looks like David Bionor's - some of the the best in the world, but not possible to reproduce.

Were there any branded speakers using the TAD 4003?

 

[bonzo75]

Unfortunately we can only collect thinks we can source. It looks like David Bionor's - some of the the best in the world, but not possible to reproduce.

Were there any branded speakers using the TAD 4003?

Tad monitors, like 2404. There is 2401 to 4, I forget what each one uses but I know the 4 uses the 4003 as I heard it there first before visiting Leif. Some DIYers have it

 

[Ron Resnick]

. . . Going to post some nice pics when I finish the next baffle. Won’t be long.

. . .

Bill, what will be your next steps in the evolution of this design?

How will you know when the design is "finished"?

Do you plan to commercialize the design?

 

[morricab]

I don't know what other reason is there, but that problem existed with all amps except the Mayer 46

So, I guess it's good that Bill has Mayer 46 amps or he could just write off the whole project!

 

[bonzo75]

So, I guess it's good that Bill has Mayer 46 amps or he could just write off the whole project!

Actually, he is looking to try other low watt amps, but yes it is a low watt amp thing. And no it is not the way you tried to make it sound because there are different solutions that Bill can tweak since he can build it. The Mayer 46 was off the amps tried, I guessed you consciously missed that part. But thanks for making a comment whose only purpose was allow you to roll eyes

 

[morricab]

Hi Al,

Yes if one is following the strict principles of definitions on such matters the throat of the horn would need to be narrower than the driver membrane surface area to induce the compression effect and impedance loading. That said almost nobody would use a full ranger that way because of the issues with extension unless you are using the driver in the multi-way. Also doesn’t sound too good - I did try this actually with earlier iterations. I lost too much top end for 2-way.That said the Tractrix profile itself is of course a horn and provides good spl gain from loading unlike the conical profile. Also worth noting that you get about 6dB lift from the horn in this config too.

Best wishes.

I guess technically your horns are waveguides as there is no compression chamber. Although, I think most are regarding waveguides to be constant directivity and horns not (yours are Tractrix, right?). That said, I have these 18 sound XT1464 horns that are CD but I think would be considered more horns than waveguides...the lines are a bit blurred these days. I guess you get some gain due to the increased directivity from the guide over a limited frequency range.

I remember a couple years ago at Munich there was a horn company from Czech called RD Acoustics. They were using either a Foxtex or Voxativ full range driver in a back loaded horn that was over 3 meters long. They had an option to put a wooden wave guide on the driver that would boost the mids but not really the highs. It was a much smaller waveguide than this large one you have built.

 

[Audiophile Bill]

Bill, what will be your next steps in the evolution of this design?

How will you know when the design is "finished"?

Do you plan to commercialize the design?

Hi Ron,

Thanks for the questions and taking an interest in my project. I will answer them in an order that lets my answer flow (but not in order of the questions lol).

I think your second question is very pertinent as during the design / construction process, I have found myself continuing to evolve iteratively seemingly without giving myself an ultimate stop button. I have nailed the sound presentation I am looking for now so the baffle design extension I am referring to is purely for aesthetic reasons. I want to generate a smoother line transition from the horn. I have completed my new design now so just need to build it. I will know I am final when I see this revised baffle in situ showing the flowing design lines I see on my drawings. It raises a good point though because I have been doing this project purely for the passion of design, innovation and creativity because I get so much pleasure from doing these things (interestingly I do so in my career too) but it is so hard to accept that you have arrived at the “final - final” goal. Clearly this would not have been the case if I had been undertaking this adventure with strict timelines and budgets for commercialisation.

This brings me onto your third question. I have been so pleased with how the project has “turned” out (pun intended) and the sonic and design feedback I have received from Marc / Ked (but also non audiophile friends at home and family including my ruthless musician father who detests around 99% of speakers) that I have indeed resolved to undertake a very small scale commercial venture. But taking such a step is a big step so it brings me onto the last (your first question) about next steps.

After the baffle completion, I will have locked down and completed the speaker. Most of the steps thereafter pertain largely to business administration.

In terms of the next build, I have already cnc machined the next chassis body waiting for joinery and assembly. The next model is the exact same topology just with a different aesthetic choice of timber (for some parts) and finish - design cues from vintage boats for this one so quite a lot more ostentatious/sexy versus the understated but sophisticated look of the present aesthetic.

I have also designed a very large multi-way project that I have started. This will doubtfully be a commercial offering owing to the sheer scale / complexity of build but it is an itch I wish to scratch. It requires me pushing the limits of what I think is possible using my techniques but is an important exercise for learning.

 

[bonzo75]

"who detests around 99% of speakers "

By this definition, I am your daddy

 

[morricab]

Actually, he is looking to try other low watt amps, but yes it is a low watt amp thing. And no it is not the way you tried to make it sound because there are different solutions that Bill can tweak since he can build it. The Mayer 46 was off the amps tried, I guessed you consciously missed that part. But thanks for making a comment whose only purpose was allow you to roll eyes

The eyeroll is because of your dogmatism...

 

[morricab]

"who detests around 99% of speakers "

By this definition, I am your daddy

For me that applies to amps...I have found that one can be relatively tolerant for many speaker types...electronics not so.

 

[Audiophile Bill]

I guess technically your horns are waveguides as there is no compression chamber. Although, I think most are regarding waveguides to be constant directivity and horns not (yours are Tractrix, right?). That said, I have these 18 sound XT1464 horns that are CD but I think would be considered more horns than waveguides...the lines are a bit blurred these days. I guess you get some gain due to the increased directivity from the guide over a limited frequency range.

I remember a couple years ago at Munich there was a horn company from Czech called RD Acoustics. They were using either a Foxtex or Voxativ full range driver in a back loaded horn that was over 3 meters long. They had an option to put a wooden wave guide on the driver that would boost the mids but not really the highs. It was a much smaller waveguide than this large one you have built.

Hi Brad,

Yes like the vast majority of 8” full ranger implementations, the execution would technically be called wave guard due to the throat size and driver membrane size without the chamber. I answered this a bit in a few posts back to Al.

Yes mine has Tractrix geometry.

Yes I know the RD speakers you refer to - I believe they are doing room treatment now. These speakers were as you say a back loaded horn with wood waveguide (Pnoe is same).

 

[bonzo75]

The eyeroll is because of your dogmatism...

The point actually was that the driver worked with the lowest watt amp we tried and not the others. There was no dogmatism it was an observation. The post also said I would like to try other low watt amps like 45s.

 

[Zero000]

Hi Ron,

Thanks for the questions and taking an interest in my project. I will answer them in an order that lets my answer flow (but not in order of the questions lol).

I think your second question is very pertinent as during the design / construction process, I have found myself continuing to evolve iteratively seemingly without giving myself an ultimate stop button. I have nailed the sound presentation I am looking for now so the baffle design extension I am referring to is purely for aesthetic reasons. I want to generate a smoother line transition from the horn. I have completed my new design now so just need to build it. I will know I am final when I see this revised baffle in situ showing the flowing design lines I see on my drawings. It raises a good point though because I have been doing this project purely for the passion of design, innovation and creativity because I get so much pleasure from doing these things (interestingly I do so in my career too) but it is so hard to accept that you have arrived at the “final - final” goal. Clearly this would not have been the case if I had been undertaking this adventure with strict timelines and budgets for commercialisation.

This brings me onto your third question. I have been so pleased with how the project has “turned” out (pun intended) and the sonic and design feedback I have received from Marc / Ked (but also non audiophile friends at home and family including my ruthless musician father who detests around 99% of speakers) that I have indeed resolved to undertake a very small scale commercial venture. But taking such a step is a big step so it brings me onto the last (your first question) about next steps.

After the baffle completion, I will have locked down and completed the speaker. Most of the steps thereafter pertain largely to business administration.

In terms of the next build, I have already cnc machined the next chassis body waiting for joinery and assembly. The next model is the exact same topology just with a different aesthetic choice of timber (for some parts) and finish - design cues from vintage boats for this one so quite a lot more ostentatious/sexy versus the understated but sophisticated look of the present aesthetic.

I have also designed a very large multi-way project that I have started. This will doubtfully be a commercial offering owing to the sheer scale / complexity of build but it is an itch I wish to scratch. It requires me pushing the limits of what I think is possible using my techniques but is an important exercise for learning.

Make something out of Ked's bits at some stage because I'll be amazed if he ever does it.

Be sure to charge him an absolute fortune, though

You can be sure he will never be happy so the constant stream of upgrade requests is guaranteed income for life!

 

[morricab]

Hi Brad,

Yes like the vast majority of 8” full ranger implementations, the execution would technically be called wave guard due to the throat size and driver membrane size without the chamber. I answered this a bit in a few posts back to Al.

Yes mine as Tractrix geometry.

Yes I know the RD speakers you refer to - I believe they are doing room treatment now. The moss speakers were as you say a back loaded horn with wood waveguide (Pnoe is same).

It seems that long horns pose a serious issue with time delay of the sound coming out of the horn vs. direct radiation. I think this could lead to a single driver sounding not so unified due to the delay line introduced by the horn for lower frequencies...That is why I think you have mated your horn with a good alternative solution that has the speed to match the single driver/horn.

I have become partial to the TQWT design, which is part horn, part reflex and allows a shortish horn (2.x meters) and some reflex loading to get solid (if not super deep) bass...much better than a true back horn that is too short.

I will hopefully move to phase III of my design by end of his year...once I have settled on a horn/driver combination. I am back to the larger horns and larger driver and it has it's own compelling benefits. I will be relying on a professsional furniture builder that I am friends with to execute my design as he has the skills to make it look beautiful (he used to build actual pipe organs in churches/cathedrals). I will get these Radian Be drivers soon to see if they are the end all, be all to go forward with.

 

[bonzo75]

"t seems that long horns pose a serious issue with time delay of the sound coming out of the horn vs. direct radiation. I think this could lead to a single driver sounding not so unified due to the delay line introduced by the horn for lower frequencies"

I think this is correct and this is what the Mayer 46 was adjusting for in the pnoe compared to other amps tried. The other more powerful amps were pushing out the bass forward at a different timing.