miniDSP Ltd, Hong Kong /
/ Features and specifications subject to change without prior notice
38
4
O
PTIMIZING
G
AIN
S
TRUCTURE
When deploying a DSP solution in your audio system, a topic that becomes more important than with analog
equipment is
gain structure
. This means that the signal levels throughout the system should be set to an
optimum
–
high enough to maximize digital resolution and minimize noise, but not so high as to result in clipping
and distortion.
The miniDSP 2x4 and kit board include a jumper to select their input sensitivity, allowing them to be used in a
wider variety of systems.
When purchased, the miniDSP 2x4 is provided in either
“A” (0.9
VRMS maximum input level
) or “B”
(2.0 VRMS
maximum input level) versions, but it can be converted between them by opening the case and moving two
jumpers.
A (0.9 V) position
The maximum input signal voltage allowed before clipping the A/D convertor is 0.9 Volts RMS.
This position is typically used when the miniDSP is connected between a preamp and a power
amplifier or power amplifiers.
B (2.0 V) position
The maximum input signal voltage allowed before clipping the A/D convertor is 2.0 Volts RMS.
This position is typically used when the miniDSP is connected directly to a source without
volume control, such as a CD player.
Note that the input sensitivity jumper setting does not affect the maximum output signal
–
it is always 0.9 V
RMS. Therefore, when the jumper is in the 2.0 V position, the miniDSP (without any other processing enabled)
has an approximately 7 dB insertion loss. If higher output signal levels are required, then the
or the
For more information on gain structure, see the app note
