Owner`s manual

Dynamic Range

Dynamic range represents the difference between the maximum signal that

can be recorded and the “noise floor”, or level of noise with no signal

present. A system with a high dynamic range will be quieter than one with a

lower dynamic range. Dynamic range is a very important specification and

Gina24 uses converters that have very high dynamic range.

Theoretically, a 24-bit system has a dynamic range of 144 dB and a 16-bit

system has a dynamic range of 96 dB. Two questions immediately come to

mind:

1) Why does Gina24 only have a dynamic range of 112 to 115 dB?

2) For mastering 16-bit CDs with a dynamic range of 96dB, isn’t

anything more than 96dB just overkill?

First, today’s analog to digital converters typically produce a full-scale input

voltage with an input of +7 dBu. If they were to have 144 dB of dynamic

range, they would have to be capable of resolving signals as small as –137

dBu (7 dBu – 144 dBu) or approximately 10 nano-volts. That’s 10

one-

billionths

of a volt! Transistors and resistors produce noise in this range

just by having electrons moving around due to heat. Even if the converters

could be perfectly designed to read these levels, the low noise requirements

of the surrounding circuitry such as power supplies and amplifiers would be

so stringent that they would either be impossible or too expensive to build.

In answering the second question, consider the fact that music is often

compressed or amplified after it is recorded, and that some headroom is

necessary when recording to avoid clipping. The only way that 96 dB

would be adequate is if all music were recorded so that the peaks were just

under full-scale and no compressing or amplification was going to be

applied after recording. Any time recorded music is amplified, so is the

noise at the low end. Gina24 has enough dynamic range to allow sufficient

headroom and post-processing to be applied while still keeping the noise

either off the CD completely or down as far as possible.