Using PA Speakers In A Home "Audiophile" Application!

With regards to the Benchmark amps, I use two as monoblocks with the Jubilees. They are extremely quiet through these big horns. But honestly no more so than any of the First Watt amps I use - 

@deep_333 You will need a low noise amp for that and also one that has low gain, otherwise the noise floor of the amp won't be much help. The Benchmark, while excellent, as over 30dB which means you'll notice noise from your front end.

Our class D amp is quiet (but not that quiet) but it only has 22dB of gain.

I think you'll have to try things out and see what works. High efficiency speakers are often a challenge that way.

SET amps often have only 15 dB of gain, sometime even less. But their noise floors are not as good as our amp but that doesn't mean they won't work. But you would be looking for low noise tubes...

I don't think an SET is a good idea with this speaker since its designed with the idea that the amp can behave as a voltage source. SETs can't do that so you'd have a tonal coloration due to frequency response errors.

@atmasphere wrote:

My concern would be breakups in the drivers, which cause distortion and harshness. PA stuff mostly does not care about that sort of thing since sound pressure is the main goal. But its a big deal with home audio speakers, where such things can shoot the product down.

I don't know the specific product referred to by poster @deep_333, but as a claim aimed at pro drivers in general your statement is incorrect. If there are breakup modes prevalent here it's most likely due to a driver section being used outside it's recommended frequency range, and not because the drivers are more prone to breakups as such than "home audio" variants or very expensive, boutique equivalents - unless we're speaking beryllium diaphragms in the MF/HF drivers, which extend more cleanly into the upper octaves for a given diaphragm diameter. Motorforce is a factor as well, but hardly applicable as a significant contributor in this context.

Moreover, as a design intended for active configuration there are obvious advantages using steeper filter slopes, and thus avoid severe driver overlapping as you would with passive designs. This not least is a factor with horn-loading. Modern pro drivers (and even ones decades old) are extremely well designed, and used within their design parameters - not least actively - will yield no effective problems with breakup modes. 

@deep_333 wrote:

Nevertheless, since this is 106 db sensitive/possibly running at fractions of a watt for home listening levels...what type of "audiophile grade" home audio amplifier might you recommend?

I can say for certain pictured PA speakers above aren't 106dB sensitive overall. The direct radiating woofers are in the 96-99dB sensitivity range, although the horns above are +100dB sensitive. If they were passively configured then the system sensitivity would be dictated by the least efficient driver section (with the horns above dialed down to match LF), which are the woofers here. Since these are intended for active config. a staggered sensitivity rating for each drivers section should be stated.

With regard to amp matching, Ralph is the meastro here in giving advice. Noise can be an issue though with +100dB sensitive drivers coupled directly to amps without any passive filters in between, which can be partly alleviated with higher impedance drivers of 16 ohms, or simply a fitting resistor size in series over the MF/HF section. 

@kckrs ​​@atmasphere , thanks

@phusis , Could you suggest an "audiophile grade" active crossover?