TL Audio M4 - Manual (Page 8)

7
M4 MIXER OPERATION
Input Selection
You must ensure that the correct input connector, mic or line, is being used from
the required source. You can select the type of input by pressing the 'LINE' switch
at the top right of each channel strip in or out. In the "up' position the mic input
is selected; depressing the 'LINE' switch selects the line input as the source. Note
that you can have mic and line inputs connected at the same time but will only be
able to select a single input at a time.
Input Gain Control
The gain control should be set to obtain the best signal to noise ratio, whilst
preserving adequate headroom. Any changes in gain level should be gradual to
avoid sudden overload or severe distortion. Extra care should be taken with
higher level inputs, and high gain settings should be used sparingly to avoid an
increase in the noise floor and the introduction of distortion.
Line Input
A typical line input will require less gain than a microphone signal as it is a 'hotter'
source. You should have the gain set to a minimum when connecting a line
input, then gradually increase it to achieve the required level.
Microphone Input
When connecting a microphone to the M4, start with the gain set to a minimum
value and gradually increase until the sound source is just tickling 0dB on the
meters when the source sound is at average output level. You can than choose
how much you would like to drive the valves to produce the required sound. If
Phantom power is needed, activate it before setting the gain by depressing the
button marked '48V' at the back of the channel strip. Although the M4 provides
48V of phantom power, microphones requiring less than 48V can still be
connected without any difficulties.
CAUTION: Operation of the phantom power switch, or plugging a microphone in
with the phantom power applied, may cause an audible click or thump in your
loudspeakers. To avoid this happening, ensure that the channel fader and stereo
master faders are set to a minimum before operating the switch or plugging in a
microphone. Switching between mic and line with high input gain settings may
also cause an audible thump if the level control is not turned down.