High efficiency horn speaker amp question

[morricab]

I respect the sentiment of you horn owners that dislike different amp topologies. And I expect, as Morricab mentions above, that to successfully multiamp (passive or active) it should be done with similar or same sounding amplifiers regardless if one uses tube or sand amps.
I'm going to try this on my Altec model 17s as I have never got them quite right with passive crossovers, and I have tried a few. I will build a First Watt active crossover and probably test this with a small 4x30w hypex class D (because I have one) or use my DIY First Watt class A amps (F6 and M2), that sound similar but not quite the same, or maybe build a second pair of Neurochrome Modulus-86s. My day to day Altec A5s seem to be more forgiving and sound fine with passive crossovers (although of course not the same with different crossovers). I have tried 3 different crossovers, and now prefer a Hiraga inspired crossover.
Just to correct a misunderstanding earlier in the thread, the Neurochrome Modulus-86 is a class AB amp, not class D. Inexpensive to build and quite good for its price

Is there a kit or something for a First watt active crossover?

 

[morricab]

@Solypsa, no I havent tried minidisp, but thought about buying minidisp for experimenting but not done that yet.

I bought it for experimentation but it works so well that for now it stays...still hoping to find a truly excellent analog active. The secret is to buy the one that is only digital out and use really good DACs instead of the mediocre implementation that companies like mini-dsp usually do.

 

[morricab]

I respect the sentiment of you horn owners that dislike different amp topologies. And I expect, as Morricab mentions above, that to successfully multiamp (passive or active) it should be done with similar or same sounding amplifiers regardless if one uses tube or sand amps.
I'm going to try this on my Altec model 17s as I have never got them quite right with passive crossovers, and I have tried a few. I will build a First Watt active crossover and probably test this with a small 4x30w hypex class D (because I have one) or use my DIY First Watt class A amps (F6 and M2), that sound similar but not quite the same, or maybe build a second pair of Neurochrome Modulus-86s. My day to day Altec A5s seem to be more forgiving and sound fine with passive crossovers (although of course not the same with different crossovers). I have tried 3 different crossovers, and now prefer a Hiraga inspired crossover.
Just to correct a misunderstanding earlier in the thread, the Neurochrome Modulus-86 is a class AB amp, not class D. Inexpensive to build and quite good for its price

After I went to all SET, the overall sound improved even though they are different amp types, tube types. I might eventually get another Ayon Spark so that I have the same exact amp on both the horn and the Supravox mid/bass but for now this is a very good sound I am getting.

 

[kjartanb]

@morricab yes you can buy an active 2way crossover kit here https://diyaudiostore.com/products/diy-biamp-6-24-crossover

 

[Solypsa]

I bought them to use in this manner with my 300b SETs up top and have the F4s on the bass (driven by the 300bs), but they ended up being so good that I sold my SETs and just used the F4s for everything.

Just thinking out loud about the F4 following a tube amp; given the 47k input of the F4 wouldn't this allow the SET amp that precedes it to use a different output transformer since it is not connected to a low impedence ( speaker ) load?

 

[cal3713]

Just thinking out loud about the F4 following a tube amp; given the 47k input of the F4 wouldn't this allow the SET amp that precedes it to use a different output transformer since it is not connected to a low impedence ( speaker ) load?

I think most people using the F4 in this way are still driving the upper frequency drivers directly with the SET while running a speaker-level-to-RCA cable over to the F4 for bass duties... but if you're instead using the SET as a pure voltage source and feeding it to a full-range F4, yes. You can also really easily modify the F4 to have an input impedance of up to 250k by just replacing a single resistor (with no performance hit).

In my setup, I do all voltage gain with the DHT EML20As (with monolith amorphous output transformers), and then provide current gain with the F4. I love how this sounds. Like I said earlier, the F4 is really transparent to your source.

https://www.firstwatt.com/pdf/prod_f4_man.pdf

 

[cal3713]

6moons has a really thorough discussion of all the connection options as well: https://6moons.com/audioreviews/firstwatt6/f4.html

 

[Addicted to hifi]

I have listened to a few very efficient horn speakers in the past driven buy very low output amps and it was excellent at low to medium volume, but once you try to go past these levels the sound deterioration was noticeable.

 

[morricab]

I have listened to a few very efficient horn speakers in the past driven buy very low output amps and it was excellent at low to medium volume, but once you try to go past these levels the sound deterioration was noticeable.

Not sure what you heard but horns play cleaner louder than conventional speakers.

 

[Addicted to hifi]

Not sure what you heard but horns play cleaner louder than conventional speakers.

Absolutely horns play cleaner and louder and I am a huge fan of horns and own 3 pairs of them.I’m saying with low watt amps the amps can run out of power.my evs are108db efficient and i run a 450 watt amp with them.the result is I can play very loud when I feel like it Without and distortion or power issues.

 

[morricab]

Absolutely horns play cleaner and louder and I am a huge fan of horns and own 3 pairs of them.I’m saying with low watt amps the amps can run out of power.my evs are108db efficient and i run a 450 watt amp with them.the result is I can play very loud when I feel like it Without and distortion or power issues.

I guess it depends on what you mean by low watts...I use 25-40 watt SETs and this runs my horns just fine.

 

[Hear Here]

Absolutely horns play cleaner and louder and I am a huge fan of horns and own 3 pairs of them.I’m saying with low watt amps the amps can run out of power.my evs are108db efficient and i run a 450 watt amp with them.the result is I can play very loud when I feel like it Without and distortion or power issues.

I used to run my first horns (102 dB) with 6 watts of PX-25 SET. Ample volume available and exceptionaly nice sound on small scale music but rather out of its depth with big orchestral stuff. Switched to big 845-based monos but now using 200 watt Class D with my 3rd pair of horns (107dB). You can't have too much of a good thing! Very happy.

 

[Mikem53]

I have listened to a few very efficient horn speakers in the past driven buy very low output amps and it was excellent at low to medium volume, but once you try to go past these levels the sound deterioration was noticeable.

How does a 108db sensitive horn require more than a few watts ? Is the sensitivity spec actually much lower? I get having some headroom for peaks and such, but hundreds of watts ?
@Carlos269 is running 1.6wpc from a 45 into a less sensitive speaker with plenty of kick, from what I heard via his recordings.
Just curious as I have conventional speakers that are rated at 95.5dB, 3 drivers/crossover and it requires some current to overcome these obstacles, but I thought the magic of horns came from the ability to use SET low power amps.

 

[cal3713]

How does a 108db sensitive horn require more than a few watts ? Is the sensitivity spec actually much lower? I get having some headroom for peaks and such, but hundreds of watts ?
@Carlos269 is running 1.6wpc from a 45 into a less sensitive speaker with plenty of kick, from what I heard via his recordings.
Just curious as I have conventional speakers that are rated at 95.5dB, 3 drivers/crossover and it requires some current to overcome these obstacles, but I thought the magic of horns came from the ability to use SET low power amps.

I think it's useful to write out the math even though we all know it. You be the judge...

108db - 1w
111 - 2
114 - 4
117 - 8
120 - 16
123 - 32
126 - 64
129 - 128
132 - 256

 

[ddk]

How does a 108db sensitive horn require more than a few watts ? Is the sensitivity spec actually much lower? I get having some headroom for peaks and such, but hundreds of watts ?
@Carlos269 is running 1.6wpc from a 45 into a less sensitive speaker with plenty of kick, from what I heard via his recordings.
Just curious as I have conventional speakers that are rated at 95.5dB, 3 drivers/crossover and it requires some current to overcome these obstacles, but I thought the magic of horns came from the ability to use SET low power amps.

The numbers are simply that, there's more to the physics than a basic sensitivity declaration. The notion that all horn speakers can be driven by low powered SETs is a total fallacy, in fact today most require at least 100 watts and many of them even require a high current solid state amplification. There's a reason for so many half active speakers on the market. There's no magic to the average horn speaker.

david

 

[morricab]

The numbers are simply that, there's more to the physics than a basic sensitivity declaration. The notion that all horn speakers can be driven by low powered SETs is a total fallacy, in fact today most require at least 100 watts and many of them even require a high current solid state amplification. There's a reason for so many half active speakers on the market. There's no magic to the average horn speaker.

david

SUrely you are referring to those in the low 90db range and not something like Avantgarde that is 107 or more db/watt. You cannot really call JBL monitors horn speakers just because they have a horn tweeter...they are fairly conventional reflex loaded speakers with a horn tweeter. Real horns are driven just fine from a few watts and usually sound terrible with high powered solid state. Not sure what you are referring to by "average" horn speaker.

 

[ddk]

SUrely you are referring to those in the low 90db range and not something like Avantgarde that is 107 or more db/watt. You cannot really call JBL monitors horn speakers just because they have a horn tweeter...they are fairly conventional reflex loaded speakers with a horn tweeter. Real horns are driven just fine from a few watts and usually sound terrible with high powered solid state. Not sure what you are referring to by "average" horn speaker.

Try driving the Trios with an average SET and then drive them with a 100w or more push/pull amp. For that matter how many production full range horn speakers do you know of today that can be properly driven with your typical low powered SET; 6-12w average? It's not a knock on the AV's just the reality as it is for Tannoys with 15" drivers, both vintage and modern.

I wasn't thinking only of JBL but you don't consider JBL Everests, K2s and M2 series horn speakers?

david

 

[Atmasphere]

I thought the magic of horns came from the ability to use SET low power amps.

Not at all!

There are a good number of amps that sound as good or better than SETs on horns. The advantage of horns is they can have lower distortion, the controlled directivity can help prevent early reflections (usually from side walls, which causes harshness) and of course the higher efficiency allows for less thermal compression.

As far as amps go, as long as the amp has certain distortion characteristics it will sound great on a horn. One character is that distortion linearly decreases as power is brought to zero (SETs do this quite well). Some amps have increasing distortion as power is decreased and don't work as well on horns because of the lower power requirements of a horn.

Another nice distortion character is that the 2nd or 3rd harmonic (both of which are treated the same by the ear) made by the amp is in enough quantity higher than the higher ordered harmonics that its able to mask those harmonics from being audible (when audible, which is really common, they are perceived as brightness and harshness). SETs are good at this but other amps are too and often with much lower overall distortion, allowing the latter greater neutrality and transparency, since distortion masks detail and is always assigned a tonality by the ear.

Finally, the distortion measured at 100Hz should be the same as measured at 1KHz or 10KHz. If not, the amp will sound brighter and harsher. Many amps that employ feedback will have higher distortion as the frequency is increased so won't pass this test. Not surprisingly, this is why amplifier distortion is typically measured only at 100Hz. Amps that employ no feedback will have this desirable character unless their high frequency bandwidth is compromised, so smaller SETs can do this while higher powered ones have trouble. Not surprisingly, its the lower powered SETs that people talk about in reverent whispers like those based on the type 45 power tube. But there are other tube amps and also some solid state amps (including class D) that run no feedback. Amps that employ a great deal of feedback can have this character too- the feedback has to be in excess of 35dB, so that the amp can compensate for the distortion caused by the application of feedback itself.

Bottom line: horns help SETs out a lot, but its not the other way around.

 

[morricab]

Try driving the Trios with an average SET and then drive them with a 100w or more push/pull amp. For that matter how many production full range horn speakers do you know of today that can be properly driven with your typical low powered SET; 6-12w average? It's not a knock on the AV's just the reality as it is for Tannoys with 15" drivers, both vintage and modern.

I wasn't thinking only of JBL but you don't consider JBL Everests, K2s and M2 series horn speakers?

david

I consider the JBLs more hybrids...like the Dynamikks speakers I own. Same for speakers like Altec model 19s or 604 based speakers. Not that this is bad...in fact it can be brilliant as you know.

I actually find a good 20-40 watt SET more dynamic sounding that a 100 watt/PP amp that almost certainly is using negative feedback and therefore has restricted dynamic expression.

I may not have heard Avantgarde with a 100 watt PP amp but their own SS amps sounded like crap on their speakers and a good tube amp like from Audiopax (both the SE model and their newer PP models) or from Thomas Mayer sounded heavenly. If I needed more shove with Avantgardes I would use a 845, 211, 813, 6c33, GM70 or parallel 300B amp rather than anything pushpull.

On my own speakers (97db), I have had very good results with everything SET from about 20 watts and up. My current amp (AC Genus, 25 watts) sounds virtually limitless on this speaker. Others I have had (JJ322, Wall Audio M50 monos, Ayon Crossfire III, NAT Symbiosis SE, Ayon Vulcan Evos (for review), Ayon Spark, MasterSound Dueundici (borderline at 11 watts, KR Audio VA350i) all worked brilliantly (although each clearly had it's own character).

On my more sensitive system (99db bass and 110db horn welded with a digital xover) I find that I need very little power. There the MasterSound at 11 watts sounded like a Goliath and the 5 watt PP triode amp I had on the horns a Juggernaut. Now I have the Ayon Spark (I like the sound of the 6C33C and Ayon executes this well) on the bass and 6 watt 300B monos on the horn. It can do big symphony stuff very loud without strain with this level of sensitivity and no passive crossover.

I wouldn't care what you drive Tannoys with...not my cuppa tea. I would; however, one day get my hands on a pair of Altec 604s...those sound interesting. The big JBLs, Like yours, would also be of interest one day if I have space for them.

 

[Hear Here]

Real horns are driven just fine from a few watts and usually sound terrible with high powered solid state.

Wherever do you get that from? Yes, they can be driven by a few watts, but also sound just as good driven by carefully chosen high powered SS amps.

Horn speakers can sound as good powered by a SS amp as by an SET. If the SS amp is carefully chosen of course. My horn speakers were subjected to several SS amps before they sounded better than they did with SETs, but I've now cracked it and moved away from valve amps altogether and am very content. I use a 200 watt Class D with my 107 dB horns