SETs and Horns

[MarcelNL]

A friend of me is doing that for his horn project (basically full range, but with a sub to support the lowest of low), don't ask how much time the optimization of the process did cost him already as he is also redesigning the diaphragms...think years.

 

[Rensselaer]

I would say "horn-loaded" as the driver feeding the horn could be any of several different types, including conventional cones. Separately, a driver can be back horn-loaded, as in the Tannoy Westminster Royal GR.

I am much more inclined than most to use higher than typical power on high sensitivity loudspeakers. So I am answering your questions more from the point of view of horn loudspeakers than from the point of view of SET amplifiers.

I am answering these questions having in mind the very best and most ambitious speakers of each topology I have heard.


1. In which areas to SET/horn systems excel?

midrange realism, naturalness and presence

reproduction of the sounds of brass instruments

dynamics and "jump factor"

wider listening zone (no narrow "sweet spot")

Horn-loaded bass can sound very "fast."

An overall sonic presentation which is different from any other speaker topology in that horn speakers project the sound towards you in an energetic way that contributes to "aliveness," presence and realism.

2. In which areas can they not even be matched by other types of systems?

the reproduction of the sounds of brass instruments

I think there is something about the way horn-loaded loudspeakers reproduce the sounds of brass instruments which is consonant with the way those instruments themselves produce sounds.

If my primary musical genre interest were jazz, I definitely would have a horn speaker system. If my primary musical genre interests were jazz and classical, I probably would have a horn speaker system (unless I could have a Wilson XVX + Subsonics in which case it would be very difficult to make a decision).

3. Are there any sonic drawbacks to SET/horn systems, in the sense that there are other system types that just can do certain things better?

I find almost all contemporary design horn speakers to be a bit aggressive-sounding and fatiguing. The Tune Audio Avaton and the Cessaro Zeta and the Pnoe are my only three exceptions to this personal subjective experience. For example, I have yet to hear any Avantgarde or Acapella speaker system which I did not find a bit fatiguing.

I continue to feel that, for me, there is something slightly more transparent and in-the-room real about the way planar speakers reproduce vocals than any other speaker topology I have heard.

I think big cone speakers systems with a lot of driver surface area in the midrange and from the midrange on down can reproduce piano and big classical symphony orchestra at least as well as big horn speaker systems.

4. How much money do you have to spend on an excellent SET/horn system? How much money do you have to spend on a good SET/horn system?

Small horn speakers don't do the trick for me. I feel the same way about planars.

Unfortunately, with contemporary designs the horn loudspeaker system has to be big (and this inevitably means expensive) to achieve the sonic attributes I am attributing to them. (I have never heard from a 30" tall, two-way JBL or similar what I have heard from big horn systems.)

5. What about the question of the oft-mentioned horn colorations? Are they still a concern in modern horns? Are they a concern in vintage horns?

I don't know what you mean here by "colorations." (Is ruler-flat frequency response which sounds unnatural and unrealistic a "coloration"?)

I think some people refer to horn "colorations" as the horn "shouty-ness" phenomenon or the "cupped hands" phenomenon. I don't hear either of these on the big horn loaded speakers I have heard.

I will define "coloration" here as frequency anomalies. Other than the Shindo system Keith took me to hear in Hollywood, which sounded to me like bourbon dripping down a warm brownie, I do not think horn-loaded speakers have any ubiquitous infirmity regarding colorations.

I had horns that did shout. They were BD-Design tatrix horns designed to boost down to 150 Htz from single hi-efficiency mid-range speaker. Mine were powered by a pair of Lowther PM-3 speakers. Bert Doppenburg (designer of BD-Design horns in the Netherlands) advised me that Lowthers have "Hi-Ferric" metal filings glued onto the voice coils that eventually get loose and obstruct the coils passage, so I ordered my PM-3 speakers special, silver voice coils and no "Hi-Ferric" coating. Bert advised me that I may have eliminated the Hi Ferric problem but the cone shape/manufacturing of Lowthers caused a mid-frequency augmentation and that would cause a shout, and he was correct. They did sound fantastic playing horns, but also tended to shout. He advised I change my Lowthers for AER speakers (Germany) and I would eliminate the shout, but they cost a bundle. I now use Thrax Lyra reflex speakers, and they sound great, but I do miss the "presence" of horns.

 

[cal3713]

has anyone ever tried to convert a horn driver to a Field coil like this one?
Altec are expensive and rare, is equipped with a new aluminum diaphragm.

Field Coil Portal

View attachment 76272

Good find. And hard to argue with the measurements they provide there.

 

[Atmasphere]

Do you have any references on the Alnico speakers having lower sag that other more powerful modern magnets?

No and I wish I did. I was taught that in school decades ago. I'm sure references are out there but weeding through google's hits on screen door magnets and the like makes it hard, at least with the search vectors I've tried.

has anyone ever tried to convert a horn driver to a Field coil like this one?
Altec are expensive and rare, is equipped with a new aluminum diaphragm.

Yes, although not Altec. The drivers in my speakers are converted JBLs IIRC.

 

[MarcelNL]

google has come to a point where it's almost useless for anything non commercial, try duckduckgo (I know it's a crappy name), it weeds out most commercial noise.

 

[morricab]

Supravox are still making field coil versions of their drivers. The EXC range. I am about to try their 285 version after trying their regular 285.

Are you using them for bass or something else?

 

[morricab]

Was looking into the Fertin drivers for FLH application. They had too low sensitivity (~93dB) and low power handling for what I was looking at doing.
They have a strong following though.

Heard them in the Black Forest Audio “Helix to Heaven” speakers augmented with huge Onken box subs. All powered by Kondo...pretty amazing although a bit too colored ultimately.

 

[Audiophile Bill]

Are you using them for bass or something else?

yes I designed a big front loaded mid bass horn that I am using in my multi-way project

they are ruler flat from 58hz to 650hz @ 110dB (wall placement) on my simulation in Hornresp - probably the best simulating driver I have yet modelled

 

[DasguteOhr]

Good find. And hard to argue with the measurements they provide there.

With a multi-cell horn, I don't think deeper than 250 to 300hz. This is a Horn made from Dietmar in Germany.

 

[DasguteOhr]

No and I wish I did. I was taught that in school decades ago. I'm sure references are out there but weeding through google's hits on screen door magnets and the like makes it hard, at least with the search vectors I've tried.

Yes, although not Altec. The drivers in my speakers are converted JBLs IIRC.

what a series from jbl if i may ask. I still have a couple lying here

 

[Atmasphere]

what a series from jbl if i may ask. I still have a couple lying here

All I know is that the driver is 3" and bolts up to a 500Hz horn. But I'll see if I can find out.

 

[DasguteOhr]

All I know is that the driver is 3" and bolts up to a 500Hz horn. But I'll see if I can find out.

Thanks, i have one pair 2441 same 500hz to 14- 15khz.
For Year 2022 the next project , first comes a Preamp with 6H30 tubes

 

[Atmasphere]

first comes a Preamp with 6H30 tubes

This to be taken in the FWIW department; grain of salt, etc.... but if you're building this up yourself, you might want to look into something that uses the 6SN7 instead. Tubes from the 6922 family of frame grid triodes seem to be prone to microphonics (they are meant for instrumentation so are very linear, where microphonics isn't as much of a concern) so you really have to hand pick them to find a good example. Not saying that 6SN7s don't have this problem too but its easier to find ones that do the job and you have an immense number of NOS types to play with as well as new boutique types. I think they sound better too but that's me.

 

[DaveC]

This to be taken in the FWIW department; grain of salt, etc.... but if you're building this up yourself, you might want to look into something that uses the 6SN7 instead. Tubes from the 6922 family of frame grid triodes seem to be prone to microphonics (they are meant for instrumentation so are very linear, where microphonics isn't as much of a concern) so you really have to hand pick them to find a good example. Not saying that 6SN7s don't have this problem too but its easier to find ones that do the job and you have an immense number of NOS types to play with as well as new boutique types. I think they sound better too but that's me.

I'll agree with you this time! My pre has a heater voltage switch so I can use either 6SN7 or 12SN7, which gives you lots of options. 6922 and 6H30 can give very good results too but I like the larger octal tubes.

I prefer the Soviet metal base versions of the 6SN7 and 6SL7, my system uses these + EL34 output. I also don't think people give EL34 enough credit, they can be really good and are inexpensive. I've directly compared it to a friend's Fi 2a3 mono amps and he sold them after hearing my humble El34 amp.

 

[Atmasphere]

I've directly compared it to a friend's Fi 2a3 mono amps and he sold them after hearing my humble El34 amp.

Is your amp ultralinear?

 

[DaveC]

Is your amp ultralinear?

No, it's in triode mode. I've rebuilt it a bunch of times over the years, using all film caps and a fairly complex driver section with it's own PS makes it sound different from a typical EL34 SET.

 

[DasguteOhr]

This to be taken in the FWIW department; grain of salt, etc.... but if you're building this up yourself, you might want to look into something that uses the 6SN7 instead. Tubes from the 6922 family of frame grid triodes seem to be prone to microphonics (they are meant for instrumentation so are very linear, where microphonics isn't as much of a concern) so you really have to hand pick them to find a good example. Not saying that 6SN7s don't have this problem too but its easier to find ones that do the job and you have an immense number of NOS types to play with as well as new boutique types. I think they sound better too but that's me.

two 6h30 tubes in parallel per chanel,one gain stage operating point at 85 volt / 40mA. I heard something like that from a friend. is really good I still have good reflector tubes here for this. I'll show it here when it's done. thank you for your tip with 6sn7 tubes

 

[Atmasphere]

two 6h30 tubes in parallel per chanel,one gain stage operating point at 85 volt / 40mA. I heard something like that from a friend. is really good I still have good reflector tubes here for this. I'll show it here when it's done. thank you for your tip with 6sn7 tubes

You can always do that with 6SN7s too. Essentially each triode is running 10ma which is no worries for a 6SN7. You'll have a bit less gain, which I've found to be handy with digital sources. Are you planning a regulator scheme as well?

No, it's in triode mode. I've rebuilt it a bunch of times over the years, using all film caps and a fairly complex driver section with it's own PS makes it sound different from a typical EL34 SET.

It really is helpful for the driver/voltage amplifier section to have its own power supply. That way no matter what happens with the output section its power supply can't influence what's upstream, although if its a single-ended output that probably doesn't amount to much. Have you ever run single-ended using an OPT that has an ultralinear tap? If the tap is set properly the linearity curve looks just like a triode.

 

[DasguteOhr]

You can always do that with 6SN7s too. Essentially each triode is running 10ma which is no worries for a 6SN7. You'll have a bit less gain, which I've found to be handy with digital sources. Are you planning a regulator scheme as well?

It really is helpful for the driver/voltage amplifier section to have its own power supply. That way no matter what happens with the output section its power supply can't influence what's upstream, although if its a single-ended output that probably doesn't amount to much. Have you ever run single-ended using an OPT that has an ultralinear tap? If the tap is set properly the linearity curve looks just like a triode.

Yes ,Voltage Regulator and High Curent source each 6c19 12bh7,each plate 85V 40mA.
you can drive 20m cable no problem or several power amplifiers in parallel. It is important that the power dissipation of the tube does not exceed 7 watts, then the anodes start to glow. we have tested.


Sorry for Offtopic

 

[Atmasphere]

Yes ,Voltage Regulator and High Curent source each 6c19 12bh7,each plate 85V 40mA.
you can drive 20m cable no problem or several power amplifiers in parallel. It is important that the power dissipation of the tube does not exceed 7 watts, then the anodes start to glow. we have tested.

Yes, its nice to be able to drive long interconnects; that allows you to run short speaker cables. IME this gets you greater resolution and impact.

Regarding the regulation, the regulator is a power amplifier in its own right and needs linearity and bandwidth. While the linearity is often no problem, the bandwidth can be, especially for a tube regulator. You want the output impedance of the regulator to be flat across the entire passband. With tube regulation you often need substantial bypass capacitance to deal with the impedance curve climbing as the bandwidth falls off at higher frequencies. In a nutshell this is a lot easier to get right if you used solid state regulation- you can easily get one or two orders of magnitude lower noise out of the regulator.