Post by Michael Lawrence on Jul 31, 2018 15:10:50 GMT
Ah, this is actually a pretty complex topic.
Don't think frequency, think time. In this context, resonance just means that the sound takes longer to decay at some frequencies than others. What a lot of people miss, though, is that the rise time of the resonance is the same as the decay time of the resonance. Put differently, if a resonance takes 200 ms to decay 10 dB, it also takes 200 ms to rise by 10 dB. Paradoxically this means that the narrower-Q resonances - the ones which look most alarming on a screen - actually are the least likely to cause audible issues when listening to music because it takes sustained energy at that frequency to excite the resonance. Think about how a wine glass resonates nicely when you drag a finger around the rim - but realize that it takes a long time to build up that resonance, too. It's the same idea. REW's slow sine sweep gives them time to build, more so than music does.
All of this was examined in some experiments that are described in Dr. Floyd Toole's book "Sound Reproduction" starting on page 157 and starting on page 444. Dr. Toole was one of the technical consultants on Ethan's book. Very generally speaking, the experiments found that lower-Q resonances tend to be more audible under normal listening conditions, because they are excited by a wider range of frequencies and reach full amplitude much quicker.
Like I said, there's a lot going on here, but hopefully that is a starting point for your own research.
Nice post, Mr. Lawrence. I didn't know that but I'm happy to hear it. Patate, an organ has a distinct and continuous amplitude envelope whereas most basses, when plucked, have a much quicker decay. Based on that alone, I'd say that, yes, and organ is more likely to excite a narrow resonance if played with sustained notes.