Thank you, cd318.
Like you, I am "inclined to believe that a great speaker should still sound good in any room." My standard example is a grand piano: Sure it will sound best in a good recital hall, but it won’t suck in your kitchen unless you play it too loud. Imo this is because the piano’s reflections are spectrally correct, so their contributions are almost always beneficial (though they can overwhelm in your kitchen if you play too loud).
You also said, "How much life/ reflected sound you want in a room will always be a matter of personal choice." I am currently working on a design that allows adjustments to the reverberant field independent of the first-arrival sound.
Here are some of the general principles I try to follow, as far as the reverberant field and its effect on timbre:
1. The reverberant field’s spectral balance should be a good match for the first-arrival sound. It will have a little bit less high frequency energy because of absorption, but not by as much as is typically caused by beaming. When there is a significant spectral discrepancy between the first-arrival sound and the ensuing reflections, those reflections do not enhance the timbre very much. They can even cause listening fatigue.
2. Early reflections are undesirable, but late reflections are beneficial, provided they are spectrally correct. In general reflections arriving within 10 milliseconds of the direct sound tend to degrade clarity (though they can still enrich the timbre), and in general reflections arriving later than 10 milliseconds enrich the timbre without degrading the clarity. In fact they can actually improve the clarity by giving the ear multiple "looks" at complex sounds (assuming the reflections are spectrally correct).
3. There can be either too much or too little energy in the reverberant field. Too much and clarity and imaging are degraded; too little and timbre is degraded.
For some anecdotal evidence of the above, consider Maggies. Maggies have a spectrally-correct backwave, and when you position them far enough out into the room (five feet gives about 10 milliseconds of delay on that backwave reflection), that’s when the magic happens. Imo Maggies might generate a little bit more reverberant energy than is absolutely ideal, but if you sit pretty close to them the ratio of direct to reflected energy is increased, and clarity is improved.
@cd318, if you will be at the Rocky Mountain Audio Fest in early October, please stop by Room 3002 in the Tower. We’re going to try to make the room seem bigger than it actually is by manipulating the reverberant field. We think timbre will also benefit along the way.
Duke
