MPA575 Owner’s Manual
7/2014
7
QUICK START GUIDE
Optimizing the MPA575 settings involves five easy steps:
1. Disengage the EQ and HPF.
2. Increase the Gain stepped switch until the red O/L LED lights infrequently, then reduce
the stepped switch by one step.
3. If the compressor is used, first adjust the Side Chain (SC) EQ to position 0 for flat
frequency response.
4. Adjust the compressor Threshold for infrequent lighting of the yellow activity LED.
5. Adjust the Output Level pot until the signal level being provided to subsequent
equipment is appropriate.
Once these basic steps have been taken, the timbre may be tweaked by experimenting with
the Mic Load setting, the main EQ, High Pass Filter, the Compressor threshold, and the
compressor Side Chain (SC) EQ.
It is worth noting that extra effort has been made for the MPA575 design to automatically hold
the total gain constant to within +/- 0.2 dB as the Mic Load switch is changed and as the EQ is
switched in and out. This allows easy A/B auditions of different mic loads and EQ settings
under controlled conditions, rather than having loudness differences obscure true differences
in timbre.
The Compressor side chain EQ can have a surprising effect on the compressed audio timbre.
The side chain EQ uses the same design as the Main EQ, but the side chain EQ is used only
to trigger the Compressor gain reduction, not equalize the Main audio path. As such, when the
side chain EQ is set to emphasize certain frequencies, those frequencies are compressed
more than the others. For example, a sibilant voice or instrument with excessive high
frequency content can be selectively compressed by turning the side chain EQ clockwise past
the center position. High frequencies are compressed, and low frequencies are allowed to
pass with little compression. The amount of compression can be set by adjusting the
Threshold level.
Another useful feature to experiment with is the Compressor Pre- Post-EQ button. This button
allows you to choose whether to place the Main EQ before the Compressor or after the
Compressor. This way, the Main EQ can be used as a tool to only equalize the music
(Compressor Pre-EQ), or can be used as a tool to affect to which frequencies compression is
applied as well as to equalize the Main audio path (Compressor Post-EQ).
