Originally Posted by clearwaterms
So, lets modify the question, how does a compression driver compare in terms of SQ when volume isn't the driving factor?
Ok this question is a better question. Still not totally apples to apples, but fair enough. I don't see how the root of the concerns can be asked any better way.
I think compression drivers really excel in dynamics, and this isn't totally limited to high SPL dynamics. Geddes goes on and on about compression even at lower levels, and he makes an excellent case for it. As for my personal experience, this does hold true. The CD is very clean and effortless. Effortless is really a good way to describe the difference between domes and CDs. Ribbons are also pretty effortless, but have many other issues. So even in your low SPL scenario I'm still going to give the CD the upper hand for dynamics.
For flatness of response, it's really hard to beat a dome. I mean, really, even in a waveguide they are mostly all a straight line. If you like simple cross overs, it's hard to beat the dome. I've used the SB29RDCN-0004 in about 4 or 5 different waveguides and with a very simple XO I get +/- 1db. That's tough to beat. Also good domes have a very tight impulse response/ CSD. So that can be good. How audible, I dunno. The dome also will extend to 20khz and beyond fairly easily. The CD doesn't.
As for the subjective side of things, it depends. This is where it's not apples to apples. It depends on implementation and budget. Going to go with big cabs, $1000 budget, and ok with an active or very complex cross over? I really think the compression driver with a quality hifi waveguide is going to sound better. It's going to sound very life like, dynamic, clear, clean, effortless, and powerful.
Gonna spend $200 for a pair of speakers and need it to be simple? Go with the dome. CDs are expensive and a waveguide adds another cost, and at that budget they get very very bad. (although the DNA-150 is a real giant killer for $15). I did about 5 different small/budget designs with the DIYsoundgroup stuff when it first came out to pump them up. All of them are ok, except your can get the same thing with a dome speaker with less complexity. So they haven't been very popular, and I don't blame people.
It's the 300 to 500 $ range where it's a bit fuzzy (talking DIY costs here). Depends on what you want. Domes fit narrow speakers better. They're very smooth, easy listening, snappy. But compression drivers on big waveguides really sound like real life.
Ribbons are another story, but are to weak sauce for me. Gotta cross to high.