Universal Audio LA-3A - Manual (Page 11)

8
Stereo Setup / Calibration
1. Set the STEREO ADJ control to full Clockwise.
2. Set the PEAK REDUCTION knob to 0.
3. Set the GR / OUTPUT switch to OUTPUT.
4. Connect a signal generator to the inputs of both LA-3A units. 400 to 1000 Hz recommended.
Set the signal generator output level to produce a typical level for your application.
5. Adjust the GAIN control on each unit so the outputs are equal at O dB on each unit. External
meters can be used to view output level as well.
6. Set the GR / OUTPUT switch to GR (Gain Reduction Metering) on both units. Turn the PEAK
REDUCTION knob on just one of the two units until the meter reads -5 dB; both units should
respond.
7. Note which LA-3A is reading the most gain reduction. On this unit, turn the rear panel STE-
REO ADJ control until both LA-3A meters read the same value. The unit is now in calibration.
Bring up the PEAK REDUCTION of the remaining unit to the same numerical value to match
gain reduction.
Stereo Use
You are now ready to use the two units as a stereo pair. Typically the users adjusts both front panel knobs in
tandem to achieve matched compression and output levels. The stereo image should remain solid and both
units should compress the stereo signal equally, regardless of which side (left or right) is triggering the gain
reduction.
Applications
This manual section is for those who haven’t had a lot of experience using compressors. If the LA-3A is your
first compressor, then this section may be particularly helpful. The Compressor Theory of Operation (on page
11) is a more technical overview of compressors and how the electronic circuits work.
Control Settings
One of the reasons the LA-3A has remained a popular compressor is its simplicity of use. There is nothing
critical to adjust other than the PEAK REDUCTION and GAIN controls on the front panel. First set these two
knobs at their “0” position. Once the LA-3A input jack is connected to your input device (mic preamp, synth
output, console output, recorder output, or any other line level device) simply turn the Gain knob up to a desired
volume level. Put the GR / OUTPUT knob in the GR position. Now turn the Peak Control knob up until the LA-3A
meter reads between -3 and -5 on the meter during volume peaks. Feel free to experiment with lighter or higher
settings. Adjust the Gain knob to bring the signal up when using heavy compression. Please review the REAR
CHASSIS control settings on page 3. Our suggested default settings are:
1. LIMIT / COMPRESS switch “down”
2. MOD switch and 30/50 dB switch “up”
3. STEREO ADJ and HF CONTOUR controls full counter clock wise (as shipped)