>>My room stinks. I need some bass traps, I think
That seems to be the only general solution, although sometimes you get lucky and can shift a peak over enough to fill a hole related to a different speaker/wall distance (sort of like landscaping). I'm planning to move in 6 months but am tempted to at least play with some traps now.
>>What's the formula? Freq = distance / speed of sound ?
Wavelength = speed of sound / Freq, or Freq = speed of sound / distance.
If the round trip distance between the walls is one wavelength (ie your walls are 1/2 wavelength apart) you get a peak, ditto at 2x, 3x, 4x the frequency etc... If the round trip distance is half a wavelength (or 1.5, or 2.5 etc..) you get a null.
Same deal with speaker-to-wall distances -- if the speaker is 1/2 wavelength from the wall (ie 1 wavelength ROUND TRIP) you get a peak.
The thing I'm trying to wrap my head around is that the peaks and nulls don't seem to follow the same pattern, eg. :
Speaker is 5 feet from the side wall :
- peak when 1,2,3... wavelength = 10' (2x5'), ie 114 Hz, 228Hz (2x), 342 Hz (3x) etc..
- null when 1/2, 3/2, 5/2... wavelength = 10', ie 57 Hz, 171 Hz (3x), 285 Hz (5x) etc...
Your 63 Hz peak corresponds to having the speaker about 9 feet from some wall. I wouldn't expect that moving 5" would shift the peak that much unless you were talking about moving them relative to the back wall, where 5" makes a HUGE difference in some rooms but that is a more subtle interaction than simple room resonances and I don't know the math for that
Take all of the above with a grain of salt. I haven't done this stuff in 25 years so there's a LOT of rust. If anyone jumps in and disagrees they are probably right...
