Speed kills....

Erik, did you meant to say "the perception of speed does NOT come from dispersion alone"? Or is that in fact the main tenet of your assertion?

For speaker designers who have used the Quad 57 as their standard for natural timbre reproduction, I’ve read that in interviews many times over the years (more than a few designers have Quads in their labs), most recently by Roger Modjeski, who said in an AudiogoN post that he voiced his new Music Reference Direct-Drive ESL speaker with the 57---Eric.

Thank you both very much, Inna and Russell. At least I can still talk a good game!

Russell (or anyone else!), if by any chance you’ll be at the Rocky Mountain Audio Fest in a couple of weeks, I hope you can stop by Room 3002.

Duke

@inna asked: "Could you explain in general terms your rationale behind choosing those particular drivers for the least expensive model, forgot the name, the one with big woofer and compression driver?"

I use big prosound woofers and compression drivers (mounted to low-coloration waveguide-style horns) primarily for radiation pattern control. I want the radiation pattern to be narrow enough that, when aimed properly, we can minimize detrimental early reflections. And I want the radiation pattern to be as uniform as is reasonably possible so that the reverberant energy is spectrally correct. Sometimes this calls for an additional rear-firing tweeter.

Additional benefits of using prosound drivers include good efficiency, complete freedom from thermal compression effects at home audio listening levels, and a benign impedance curve. And ime you get more bang for your buck with good prosound drivers.

Drawbacks include large enclosure size and having to deal with anti-horn and anti-big-woofer prejudice. People think big woofers are "slow". Based on power-to-weight (applied motor strength to moving mass) ratios, my big woofer falls in between the 5.5" Scanspeak Illuminator and the 7.0" Scanspeak Illuminator. Unfortunately anti-horn prejudice is harder to overcome, as many people listen with their eyes even when they don’t hear any horn signature.

The new model I’ll be showing at RMAF has a 12" midwoofer with a significantly more powerful motor, resulting in a power-to-weight ratio that compares favorably to high-end 5" midrange cones.

Actually the compression driver has more to do with the subjective impression of "speed", but I’m not sure how to make an accurate apples-to-apples comparison with a good direct radiator dome tweeter - the specs I’d need aren’t available. But I’m reasonably confident the compression driver would do well in the comparison.

Something I found over in the prosound world is that sheer horsepower matters too. There seems to be a correlation between total motor strength and how hard a speaker "hits" down low, while power-to-weight ratio seems to matter more as we go up the spectrum. This just based on personal observations.

Duke