630 * 630
= (approximately) 400,000. 20 * 20,000 = 400,000. The 630 Hz
concept says that the best sounding audio material will have the product
of the lower and upper frequency limits = 400,000. (a
balanced spectrum)
Thus if the
system has poor low frequency response (only goes to 100 Hz) then the upper
frequency limit should be lowered to 4,000 Hz. The idea is that the
upper harmonics will not sound out of proportion. The
630 Hz concept is not a steadfast rule - one must always use one's ears
of course - but it can provide a useful strategy for the sound designer. |