Visit to Audiophile Bill to hear his horns project

[spiritofmusic]

Wait a second, I see sunshine and green grass. Surely this photo wasn't taken in the UK. Whose speakers are these ... really?!

Very beautiful all around, Bill.

I've had a beer in that garden after an audition of Bill's horns, environmental therapy.

 

[Audiophile Bill]

I've had a beer in that garden after an audition of Bill's horns, environmental therapy.

You are welcome to come back, drink more beer, and listen to these any time Marc.

 

[spiritofmusic]

Bill, you are the Vito Corleone of audio, making me an offer I can't refuse.

 

[morricab]

Been tidying up the listening room and carrying on with the back loaded horn build. Lots of coats of shellac still needed but making progress. I am running the AERs with the big field coil motor. I have an AN Kaisei secondary filter before the motor.

I am really excited about the potential for this system. It is extremely fast, dynamic, lifelike and downright musical. So far it is being fed with 1.25 watts Mayer. I have a stereo 45 amp with c3g and mercury recti to try soon. Just need to acquire a matched pair of 45 tubes. Got the others. The wires on the rug and box is the field coil supply.

View attachment 95221

What Qts are you running the driver at? Approximate sensitivity? Did you play yet with the Q to see how the bass responds?? Really curious…

 

[Audiophile Bill]

What Qts are you running the driver at? Approximate sensitivity? Did you play yet with the Q to see how the bass responds?? Really curious…

Hi Brad,

I got a new measuring tool arriving on Tuesday for all T/S parameters. At the moment I am running around 2 Tesla of flux with 13V. I would guess I am at QTS of around 0.3 but will confirm in due course. Sensitivity I haven’t measured but I can say it goes very loud indeed with my preamp half way with the 1.25 watt Mayer.

I have played with the Q a lot over last 2 weeks really getting a feel for how it plays out. I have a 2nd pair of field coil 8.5” drivers too that I have been rolling in. Photo below.

Long story short - back loaded horn, per anticipated / expected physics, prefers lower QTS and thus higher voltage. Open baffle (crude one at home) prefers higher QTS and lower voltage. Running higher QTS in the back loaded horn loses the speed, dynamics and magic for me. You gain mid bass without question but it is compromise not worth it for me.

 

[Audiophile Bill]

13kg of motor.

 

[morricab]

Hi Brad,

I got a new measuring tool arriving on Tuesday for all T/S parameters. At the moment I am running around 2 Tesla of flux with 13V. I would guess I am at QTS of around 0.3 but will confirm in due course. Sensitivity I haven’t measured but I can say it goes very loud indeed with my preamp half way with the 1.25 watt Mayer.

I have played with the Q a lot over last 2 weeks really getting a feel for how it plays out. I have a 2nd pair of field coil 8.5” drivers too that I have been rolling in. Photo below.

Long story short - back loaded horn, per anticipated / expected physics, prefers lower QTS and thus higher voltage. Open baffle (crude one at home) prefers higher QTS and lower voltage. Running higher QTS in the back loaded horn loses the speed, dynamics and magic for me. You gain mid bass without question but it is compromise not worth it for me.

View attachment 95248

Ok, that sounds about right to me. Both my speakers have Qts mid-bass drivers around 0.25. Both have great speed and slam in the midbass. The 8 inch Supravox in TQWT go deeper and the Odeons are a bit faster sounding...both sound a lot faster than nearly every standard box out there.

 

[the sound of Tao]

Hi Brad,

I got a new measuring tool arriving on Tuesday for all T/S parameters. At the moment I am running around 2 Tesla of flux with 13V. I would guess I am at QTS of around 0.3 but will confirm in due course. Sensitivity I haven’t measured but I can say it goes very loud indeed with my preamp half way with the 1.25 watt Mayer.

I have played with the Q a lot over last 2 weeks really getting a feel for how it plays out. I have a 2nd pair of field coil 8.5” drivers too that I have been rolling in. Photo below.

Long story short - back loaded horn, per anticipated / expected physics, prefers lower QTS and thus higher voltage. Open baffle (crude one at home) prefers higher QTS and lower voltage. Running higher QTS in the back loaded horn loses the speed, dynamics and magic for me. You gain mid bass without question but it is compromise not worth it for me.

View attachment 95248

all those bespoke speaker parts… OMG you’re killing us Bill lol… keep up the most excellent work!!

 

[Audiophile Bill]

Ok, that sounds about right to me. Both my speakers have Qts mid-bass drivers around 0.25. Both have great speed and slam in the midbass. The 8 inch Supravox in TQWT go deeper and the Odeons are a bit faster sounding...both sound a lot faster than nearly every standard box out there.

Yes no box has a chance keeping up with the speed. It is lightning fast transients.

 

[morricab]

Yes no box has a chance keeping up with the speed. It is lightning fast transients.

THe midbass punch I get with mine is really spectacular...it make percussion explosive, snares, toms and kick drum punch and have a lot of texture. My Odeons only do 40hz or so and the Supravox/horn setup get to around 30 according to my measurements...so no super deep bass but that midbass is something. What is your horn length and low frequency expectations for this design?

 

[Audiophile Bill]

THe midbass punch I get with mine is really spectacular...it make percussion explosive, snares, toms and kick drum punch and have a lot of texture. My Odeons only do 40hz or so and the Supravox/horn setup get to around 30 according to my measurements...so no super deep bass but that midbass is something. What is your horn length and low frequency expectations for this design?

In terms of explosive percussion - exactly. Cellos full of earthy texture.

So I have 2 internal configurations for path length at the moment. One is very short and the other is 2.4m. Each of these give me different crossover points to the sub towers.

My theory and design for this is 2 way because I am building back loaded sub towers. So effectively it will be 4 box speaker system. My sub towers design uses 2x12” per side back loaded with around 4m (will need to check my latest sims). That gets me to 32hz at 110dB+ depending on room placement.

 

[morricab]

In terms of explosive percussion - exactly. Cellos full of earthy texture.

So I have 2 internal configurations for path length at the moment. One is very short and the other is 2.4m. Each of these give me different crossover points to the sub towers.

My theory and design for this is 2 way because I am building back loaded sub towers. So effectively it will be 4 box speaker system. My sub towers design uses 2x12” per side back loaded with around 4m (will need to check my latest sims). That gets me to 32hz at 110dB+ depending on room placement.

It's good you are using backloading for the subs as well because I found it hopeless to try to match a dipole servo sub to my Odeons...I either got deep bass and cancellation in the midbass or even more midbass and still no deep bass...just didn't work.

Aries Cerat did this very nicely in 2019 with two huge backloaded subs (never became commercially available I think as such but were the basis for the new Contendo reference subs) that were placed 4 meters or so forward of the main speakers to get time alignment. The impact was very impressive and funny due to the extreme forward position of the subs...had some people scratching their heads. He used two modified Fostex Sigma 8 inch drivers (I think the same ones he used in the Symphonia's back horn) per sub. What drivers are you using for your backhorn subs?

The guy who designed a nice DTQWT used 12 inch Eminence Deltalite drivers but perhaps the Qts is too high (but for deep bass maybe a good thing?) for a backhorn (TQWT is more forgiving in this regard). Will you use Acoustic Elegance, Supravox (the 11 inch one 285 GMF is what I have been eyeing) or something else?

I am personally trying to squeeze as much out of a single box per channel as I don't have the space/permission to get crazy with 4 box systems anymore (I had big planars in multiple panel/box configs in my wild single days).

Something like this:

DTQWT-212-mkIII

But with a higher sensitivity main driver and replacing the cone tweeter with a small horn.

Or this:

DTQWT-mkIII

With 2 x 10 or 11 inch drivers and a proper horn for the highs and moving the main driver higher up the baffle. I was thinking the Supra 215-2000 or field coil and the 285 GMFs for the bass. Horn would be probably a wooden Tractrix with the Beyma CP-755Ti, which I love the sound of.

 

[Audiophile Bill]

It's good you are using backloading for the subs as well because I found it hopeless to try to match a dipole servo sub to my Odeons...I either got deep bass and cancellation in the midbass or even more midbass and still no deep bass...just didn't work.

Aries Cerat did this very nicely in 2019 with two huge backloaded subs (never became commercially available I think as such but were the basis for the new Contendo reference subs) that were placed 4 meters or so forward of the main speakers to get time alignment. The impact was very impressive and funny due to the extreme forward position of the subs...had some people scratching their heads. He used two modified Fostex Sigma 8 inch drivers (I think the same ones he used in the Symphonia's back horn) per sub. What drivers are you using for your backhorn subs?

The guy who designed a nice DTQWT used 12 inch Eminence Deltalite drivers but perhaps the Qts is too high (but for deep bass maybe a good thing?) for a backhorn (TQWT is more forgiving in this regard). Will you use Acoustic Elegance, Supravox (the 11 inch one 285 GMF is what I have been eyeing) or something else?

I am personally trying to squeeze as much out of a single box per channel as I don't have the space/permission to get crazy with 4 box systems anymore (I had big planars in multiple panel/box configs in my wild single days).

Something like this:

DTQWT-212-mkIII

But with a higher sensitivity main driver and replacing the cone tweeter with a small horn.

Or this:

DTQWT-mkIII

With 2 x 10 or 11 inch drivers and a proper horn for the highs and moving the main driver higher up the baffle. I was thinking the Supra 215-2000 or field coil and the 285 GMFs for the bass. Horn would be probably a wooden Tractrix with the Beyma CP-755Ti, which I love the sound of.

Hi Brad,

Back loaded sub horn for two reasons. Firstly horn because I need same speed and intensity as main tower. Back loaded gives me a perfect position of the upper acoustic crossover whereas front loaded didn’t.

Yes 2 Supravox 11” (already have 1 pair of the fixed magnet versions). They do field coil version too which would be fun lol. Albeit expensive.

Yes you are dialled very much into my plan!

 

[Audiophile Bill]

Brad - forgot to say. Yes I see the Contendo subs also using the Fostex Sigma albeit 3 per sub stacked so 6 I think.

I can imagine that the Fostex is exceptionally fast. I do like the Supravox 285 myself and like the idea of the cone surface area and high sensitivity of 100dB. I am using 2 in parallel.

 

[cal3713]

Great stuff here. Keep up the amazing work Bill.

Do you feel like this approach is improving on your previous horn design, or is it just something different to allow you to keep building? I'm curious how the two compare models compare to one another.

 

[Audiophile Bill]

Great stuff here. Keep up the amazing work Bill.

Do you feel like this approach is improving on your previous horn design, or is it just something different to allow you to keep building? I'm curious how the two compare models compare to one another.

Thank you for the encouragement.

I started this new build as a proof of concept mainly for fun and for a 2nd system. After a first listen, I got quite a shock at the increased dynamics, speed and musicality. The potential was clearly very high indeed and started making me take it much more seriously.

I am now very confident that it improves on my first design. It is so alive and addictive - it makes me excited to finish work and go listen. There will be folks who prefer the signature of the first design with much heavier lower mid and more relaxing coupled to deep powerful bass that can handle any genre.

The next phase I think is where I will get to a new level because the back loaded bass horns will come into play. I have already built several bass horns in the last year and there is nothing like horn loaded bass imho.

Best regards.

 

[Audiophile Bill]

Oh I forgot to say. When this system is complete I am making a mini Trio system. I already have the lower and upper mid mahogany horns so just need to make a tweeter horn and a frame. That will be fun.

 

[morricab]

Thank you for the encouragement.

I started this new build as a proof of concept mainly for fun and for a 2nd system. After a first listen, I got quite a shock at the increased dynamics, speed and musicality. The potential was clearly very high indeed and started making me take it much more seriously.

I am now very confident that it improves on my first design. It is so alive and addictive - it makes me excited to finish work and go listen. There will be folks who prefer the signature of the first design with much heavier lower mid and more relaxing coupled to deep powerful bass that can handle any genre.

The next phase I think is where I will get to a new level because the back loaded bass horns will come into play. I have already built several bass horns in the last year and there is nothing like horn loaded bass imho.

Best regards.

How big will these subs be Bill?

 

[cal3713]

Thank you for the encouragement.

I started this new build as a proof of concept mainly for fun and for a 2nd system. After a first listen, I got quite a shock at the increased dynamics, speed and musicality. The potential was clearly very high indeed and started making me take it much more seriously.

I am now very confident that it improves on my first design. It is so alive and addictive - it makes me excited to finish work and go listen. There will be folks who prefer the signature of the first design with much heavier lower mid and more relaxing coupled to deep powerful bass that can handle any genre.

The next phase I think is where I will get to a new level because the back loaded bass horns will come into play. I have already built several bass horns in the last year and there is nothing like horn loaded bass imho.

Best regards.

Very interesting. I have trust you will prove yourself right. Thanks so much for posting about the journey, it's been really educational.

 

[Audiophile Bill]

How big will these subs be Bill?

Trying to not have to compromise too much but at same time don’t want gigantic wardrobes in the room. Things evolve each day as my simulations and design evolves but as of now it is 3.5m long horn with one fold so they are around 1.85m tall.