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Balanced signals connect with either XLR connectors or TRS (tip, ring
sleeve) connectors. Mona uses XLR connectors for connecting
microphones and TRS connectors for connecting balanced line level signals.
The three sections of a TRS connector are used to transmit the three
components of a balanced signal (T = plus, R = minus, S = ground). Mona
will also accommodate the two conductor unbalanced style connector.
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
Mona 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 Mona only have a dynamic range of 115 to 116 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