Logic 401: Bit Depth and Headroom Question
Jun 6th, 2009, 02:18
I'm enjoying the Mastering Overview in Logic 401 (so far, highly recommended). One technical issue has me confused.
24-bit is supposed to give more headroom (or "tailroom" as the video suggests) than 16-bit. The graphs in the video confirm this as 24-bit is able to capture a broader range of amplitude; however, my fairly uninformed impression is that bit-depth is more a question of accuracy of the actual signal value (quantization).
For example, if a signal is between -10 and 0 (I'm just choosing numbers, the units are irrelevant for my question), 16-bit will set a "grid" of 65,536 (picture horizontal lines spanning the vertical axis) and the signal value is assigned to the closest grid value. With 24-bit it would be a much *finer* grid (16 million+) to this range (-10 to 0) and hence the grid value will always be closer to the true signal.
The video seems to suggest something else; it suggests that the 24-bit signal will use the 16 million grid values to span a wider range; e.g. -20 to 0. Is this true? In other words, we have approx. 8 million grid values for -10 to 0 and another 8 million for -20 to -10.
Any comments would be appreciated! As would any references (even some of the actual math would help!).
Thanks and looking forward to the rest of Logic 401.
-m
Reply