Speaker sensitivity vs SQ

@atmasphere wrote: 

"Harmonic orders above the 2nd decrease rather slowly as compared to a circuit that has a ’cubic non-linearity’ (produces the 3rd as the primary distortion component). An amplifier that has this quality has its distortion decreasing much faster as the order of the harmonic is increased! This is important since the ear uses higher ordered harmonics to sense sound pressure (and assigns the quality of harshness and brightness to them). IOW, an amplifier with a cubic non-linearity will sound more detailed (because distortion masks low level detail) and **smoother** because the higher ordered harmonics are at a lower level. 

"In terms of circuit design an amplifier with this characteristic must be fully differential and balanced from input to output. In this way even orders are cancelled with each stage in the amp (instead of being compounded), leaving the 3rd as the primary distortion component, at about 1/10th what you would get with a single-ended circuit, assuming that neither employs any feedback." 

VERY INTERESTING!! 

I think this explains part of the difference I hear between your amps and good single-ended triode amps, in particular:  

" An amplifier that has this quality has its distortion decreasing much faster as the order of the harmonic is increased!"  And, 

"...even orders are cancelled with each stage in the amp (instead of being compounded), leaving the 3rd as the primary distortion component, at about 1/10th what you would get with a single-ended circuit...". 

Thank you for putting this down in writing.  I copied it to a file so I can find it again.  

Duke 

Some of the older Horn loaded speakers like Altecs and JBLs that I had a lot of experience with when I was young were all very colored. Back then K horns were the best but they did not image well and though not as colored as the other horn speakers you still knew you were listening to horns.

Like any other tech, horns have benefited dramatically from the aid of computer optimization. I owned Altecs, Klipsh and EV horn systems and there's no way I would go back to them; as you say they were very colored (and lacked bandwidth, particularly in the bass). The Classic Audio stuff is a different beast altogether- neutrality is a good descriptor. The speakers produced by Audiokinesis using waveguides had a similar neutrality- you found yourself involved with the music rather than the speakers.

@mijostyn --

.. my set up is fully active but you could never use SET amps in my system. I really require big amps. I was talking in the context of very efficient speakers. SET amps are very romantic and if that is what you like then by all means but a class A SS amp particularly a Pass or Curl design is going to be more accurate, have more control over the woofer and still have a little of the romance. I would also rather buy records than $1000 tubes.

SET’s isn’t the way I’m heading either, but some of the best of them I’ve heard (300b-based by David Wright of UK) didn’t sound "romantic" per se; just natural, as I described earlier. The Ongaku (211 tubes) is warmer sounding to my ears (as is most Kondo), but I’m thinking whether this character has to do with the silver transformers mainly (instead of cobber).

@johnk --

Costs for high-eff drivers are greater, Size high- eff designs are larger can cost more to build ship take up more room at dealers and distributors.

Relative to driver diameter and weight I don’t see high eff. pro units being notably more expensive vs. hi-fi dittos, although of course they’re usually larger and take more power which then reflects their price. My main issue is taking this out of proportion with high eff. boutique drivers from the likes of TAD ($2,000 per 15" unit as mentioned by Ralph), older WE’s and Vitavox (both crazily priced), as well as (to a lesser degree) Great Plains Audio/older Altec’s or other. Brands like B&C, EV (older units in particular), RCF, 18sound, BMS and others are more fairly priced, and still great high eff. pro drivers. Some if not most of you guys commenting on this make your own speakers or are affiliated with people who are, and the drivers being used as examples here mayn’t be more widely representative.

And I will also add that buyers don’t want changes. And they have been told for decades that all horns are problematic and they bought the line that small is better. Face it would you buy a toaster that was better than others but was larger and looked not like a toaster? We are simple tools and want to blend in and conform with others not to stand out.

Well put - completely agree. I’m sure most audiophiles would find my using pro cinema speakers and 20 cf. horn variant subs to be if not laughable, then oddly.. different. Your horn set-ups are much larger still. Be that as it may I’m not going back to smaller, low eff. all-direct radiating boxes.

@atmasphere --

Thanks for your very interesting elaborations on SET’s and distortions types.

As I understand it, my speakers are currently about $33,000/pair. Mr. Mears is correct. The coupling was optimized on a computer and the result is very smooth and seamless. People often comment on hearing T3s (and T1s) that the speakers sound more like ESLs in that they are so fast and seamless. IOW no ’horn artifact’ at all.

I must have thought of the T1.5’s/T1’s re: price. $33k/pair or thereabouts for the T.3’s isn’t cheap by any stretch of the imagination, but compared to many other offerings in high-end and the JBL Everest’s mentioned earlier I’d say, from what I’ve read by you and others, that they are very fairly priced in light of the drivers used (Alnico and field coil magnets), overall finish/use of hardwood and being handmade.

@mijostyn --

Phusis, those are quite some speakers you have. What are you using for subs? They must be unusual to keep up with your main speakers.

Thanks, I think ;) The horn mounted on top of the EV main cinema speakers is the HP940 and crossed at just below 800Hz. Within a few weeks they’ll be replaced with the (much) bigger HP9040 horn using the existing (and still fitting) DH1A comp. driver. The EV bass cabs are meant for use with both of these horns, the entire speaker called either TS940D or TS9040D depending on the horn mounted to them. The intention using the bigger horn is to control directivity all the way down to the cross-over point (as low as 500Hz, if desired), and thus make for a somewhat better coverage pattern transition between the twin 15" woofers and the horn. The smaller horn I use now has a mode between 2-3kHz, whereas the bigger one moves it down to ~500Hz. Choosing a cross-over in the 650-700Hz region with the same steep slopes should avoid any outright mode issues. We’ll see.

The two subs are tapped horns (called "MicroWrecker") fitted with a 15" B&C woofer each (15TBX100). Tuned at 23 to 24Hz, 97dB sensitive, and taking up 20 cf. per horn. They are unusual, yes, not what one typically sees in hi-fi, if rarely at all. They sound different to direct radiating twin 18" ported subs (their effective air radiation equivalent) being more smooth, enveloping and effortless sounding. They fit the EV mains great.

@atmasphere --

Like any other tech, horns have benefited dramatically from the aid of computer optimization. I owned Altecs, Klipsh and EV horn systems and there’s no way I would go back to them; as you say they were very colored (and lacked bandwidth, particularly in the bass). The Classic Audio stuff is a different beast altogether- neutrality is a good descriptor. The speakers produced by Audiokinesis using waveguides had a similar neutrality- you found yourself involved with the music rather than the speakers.

The David Gunness developed HP-series horns from Electro-Voice (based on Don Keele’s Constant Directivity design’s from the 70’s) aren’t of the earliest "squeamish" types, and supposedly the bigger variants HP640 and 9040, as well as the earlier HR-series, are very well liked by audiophiles-into-horns. I’m sure the Classic Audio horns are better being newer, computer aided developments as well as their more inert hard-wood material use, albeit smaller; this is where physics and sheer size comes into place for directivity control down to the x-over point, and that’s not trivial. Compromises, compromises..

@phusis The T-1 has a 250Hz horn, using a 4" compression driver that is field coil powered. The diaphragm is made of beryllium and employs a Kapton surround, which is how it goes so low without breakups. I don't know the spec on the T-1 but I do know that the 3" diaphragm in the T-3 has its first breakup at 35KHz. The breakups are a pretty big deal; I got to hear what the regular TAD diaphragm did compared to the CAL unit and it was not subtle- much smoother!

@atmasphere --

The T-1 has a 250Hz horn, using a 4" compression driver that is field coil powered. The diaphragm is made of beryllium and employs a Kapton surround, which is how it goes so low without breakups. I don’t know the spec on the T-1 but I do know that the 3" diaphragm in the T-3 has its first breakup at 35KHz. The breakups are a pretty big deal; I got to hear what the regular TAD diaphragm did compared to the CAL unit and it was not subtle- much smoother!

The combination of larger VC diameters, beryllium diaphragms and being field coil powered sounds like a recipe for sonic excellence. That’s next level rocket stage for sure..