Phil Leigh;229064 Wrote: > I'm getting the feeling there's some slightly odd logic in play here. > > When you listen to a good recording of (say) an acoustic guitar you are > hearing the sound of an instrument in a room. What you want to hear is > that instrument in that room, since that is what was recorded - okay so > it will probably have digital reverb added to it but that doesn't > invalidate my point. However, your own room then adds its own character > to the recording when you play it back on your system. So we use RC to > reduce the effect of your own room, leaving the original recording.
I think Hugh's point is that that is very difficult to achieve. In fact it's probably impossible to achieve at anything more than one point. Suppose there's only one reflection point to worry about. When you play a short click you hear the direct sound, and a moment later the reflected sound. You can cancel that reflection out by sending out a click a little after the original one which cancels the reflected original click. But then you need another click to cancel the reflection of your cancellation click, ad infinitum. But since each click is a little quieter than the previous (since sound loses a little intensity on reflection), it's possible to do this. The corrected click will be an infinite series of clicks, each a little softer than the one before, and with a particular set of phases. However there's an additional problem - if you move a little away from the point the correction was designed to work at, the phase of the original reflected wave will change in such a way that the cancellation click doesn't quite cancel it anymore. In fact at some points the two will interfere constructively, so that the reflected sound is made twice as loud with the RC as without - plus you will hear a whole series of clicks, instead of just two. The distance to the point where the waves interfere constructively is about half the wavelength of the frequency in question. At 300Hz that's less than a meter - and given that your ears are, I don't know, 15 cm apart, there doesn't seem to be much point in trying to cancel reflections for frequencies higher than that. I think that's probably what the meridian guys were getting at. -- opaqueice ------------------------------------------------------------------------ opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=35615 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
