Horn Speaker Recommendations

2 more things...the PureAudioProject requires about 5 hours of assembly (super easy!!!), they will totally FILL your 20x 30 foot room, they are 96 dB efficient, and you can drive them with as little as a 3 -8 watt tube amp... which is what they were demonstrated with at the recent Munich Audio Show. Was that more than 2 more things?

This is a very nice speaker (I've heard it- very tube friendly), but an amp of that power will not be able to work with a room that large with that speaker- you'll run it out of gas. You'll need about 100 watts or so to really do that right. I heard it with a very nice 2A3-based SET, which was obviously running out of power when playing Porcupine Tree in a room only about 15 feet deep.

Duke's speakers (Audiokinesis) have similar efficiency (96dB) and are often higher impedance (8 or 16 ohms) and are excellent. Duke seems to also have them very fairly priced!
A word about impedance- if high end best quality sound is your goal, your amplifier investment dollar will be best served by a speaker of 16 ohms rather than 8 or 4. All tube amps will have wider bandwidth, lower distortion and and greater power driving 16 ohms (most solid state amps have lower distortion into 16 ohms as well). The distortion issue is important since the increased distortion that results into lower impedances contains higher ordered harmonics which are used by the ear to sense sound pressure- IOW the ear is keenly sensitive to these harmonics- we describe them as brightness and harshness. 

Right now I have Mola Mola Kaluga mono amps which will deliver more power than I could possible need.  

I've also "heard many" horn speakers, and it should be noted that Klipsch Heritage speakers actually DO compete with the far more exotic (re: Expensive) speakers on this list. Have good gear upstream, and, in the case of my Heresy IIIs with couple of subs, you can find magic in them there horns. Newer versions work beautifully without "major mods" and provide 99db efficiency with astonishing coherence and tonal accuracy. Never trust anybody saying anything like, "I haven't heard the newer JBLs" before assuming new ones should be avoided based on past designs. That's just lame.

The best horn systems are not the ones you find at audio dealers research horns consider a bit of DIY combinations of the best of vintage and modern are the best performing options. I wouldn't consider Klipsch unless entry-level. Avantgarde is also entry-level horn with crazy prices. The Shearer horn designs are pretty much the best horns get but they are not small small horns are wrong horns. You want a fully horn-loaded system any ported box is a compromise not really worth having if performance is the true goal.

Right now I have Mola Mola Kaluga mono amps which will deliver more power than I could possible need.

@willgolf You might want to consider that the characteristics of an amplifier like the Mola Mola may not be right for many horn designs. The reason is that when you have the efficiency of a horn, you don’t need a lot of amplifier power, so its possible to run low power tube amps (like SETs) that often don’t run any feedback. Horn speaker designers know this and expect such amps to be used with their speakers.


The way such an amplifier behaves on a load is different from how an amplifier using a lot of feedback (and thus having a really low output impedance) acts! An amp with a lot of feedback (like the Mola Mola) typically behaves as a voltage source, meaning its voltage output is invariant with load, which also means (if solid state) that its output power doubles as the load is halved.


Tube amps with no feedback tend to behave as power sources, meaning they try to make constant power with respect to load rather than constant voltage. You can read more about this at this link:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
Now most horn designers are expecting the user to use a lower powered tube amplifier. Although the Mola Mola is a good amp, because of its near-zero output impedance on many horn systems the crossover won’t work right; as an example may cross the woofer over at a different frequency than intended. The reason for this is as I explained- many of these speakers are designed for amps that are Power Paradigm devices (having an output impedance that might be several Ohms) rather than Voltage Paradigm. Any time you attempt to mix the two technologies you can expect a tonal aberration that says nothing about the quality of the equipment involved, despite the fact that both can be quite neutral if used correctly.

BTW in case its not clear, loop feedback typically used in most solid state and class D amps introduces higher ordered harmonic distortions of its own while suppressing the distortion of the amp otherwise. Because these are higher ordered harmonics, they are extremely audible as brightness and harshness (a coloration) since the ear uses these harmonics to sense sound pressure- and on that account has to be extremely sensitive in this way. This fact is a bit inconvenient, as it often means that amps with really low distortion figures might not sound as good as amps with considerably ’worse’ numbers! If the audio industry weighted the various harmonics we would have a better understanding of this fact, but they don’t so while the 2nd harmonic is recognized as less harmful than the 7th or 13th, they don’t break those numbers down to anything meaningful on the spec sheets. Horns can exacerbate issues like this, so you have to be careful.


Put more simply, the equipment matching becomes more critical when dealing with horn systems so you will want to audition your amps with the speakers you’re auditioning as well to see if you are really getting what you expect!