Instruction manual

How to Get the Best from Explorer
21
The level control, in principle, is a peak limiter. Its function is to prevent distortion due to over modulation.
Because of the singular design, it can be used as an audio AGC system with great improvement over the
'automatic record' facility of most tape recorders. The heart of the system is a voltage controlled variable
gain amplifier, with a control range of 40dB.
The Automatic Level Control (ALC) system can be set so that it operates only in an emergency ('Normal'
mode) or so that it adjusts the gain to suit the user's voice level ('Automatic' mode) or so that it operates
only at extreme levels ('Low modulation' mode).
When used in the 'Automatic' mode, the control system sets the audio gain so that the average speech
level is about 9dB below peak modulation level. This leaves headroom for the short sharp transients,
which occur frequently in speech patterns. Having set the gain, the short transients pass without distortion
and without further need to change the gain.
Connect microphone cable and adjust SET LEVEL control by one of the following methods:
NORMAL
This method suits most situations when there is time for a rehearsal and gives the optimum balance
between dynamic range and signal to noise ratio. Unless an unexpectedly loud sound occurs, the limiter
will not operate.
Adjust SET LEVEL control, while performer speaks at correct level, so the AF PEAK LED flashes occasionally
-and in the case of the TX700B ‘-10’ LED flashes regularly (for any electret microphones the setting will
be Level 4 or 5).
TX is now ready to use.