Operation Manual

USER GUIDE
30
CARE OF YOUR MIXER
GENERAL PRECAUTIONS
• Do Not obstruct any of the ventilation openings.
• Avoid storing or using the mixer in conditions of excessive heat or cold, or in positions where it is likely
to be subject to vibration, dust or moisture.
• Keep the mixer clean using a soft dry brush, and an occasional wipe with a damp cloth or ethyl
alcohol. Do not use any other solvents which may cause damage to paint or plastic parts.
• Avoid placing drinks or smoking materials on or near the mixer. Sticky drinks and cigarette ash are
frequent causes of damage to faders and switches.
• Regular care and inspection will be rewarded by a long life and maximum reliability.
GLOSSARY
AFL (After Fade Listen) a function that allows the operator to monitor the post-fade signal in a channel
independently of the main mix.
auxiliary send an output from the console comprising a mix of signals from channels and groups
derived independently of the main stereo/group mixes. Typically the feeds to the
mix are implemented on rotary level controls.
balance the relative levels of the left and right channels of a stereo signal.
balanced a method of audio connection which ‘balances’ the wanted signal between two
wires and a screen which carries no signal. Any interference is picked up equally
by the two wires, which results in cancellation of the unwanted signal. In this guide,
the term can refer to various circuit architectures. Connection details are
given in relevant sections.
clipping the onset of severe distortion in the signal path, usually caused by the peak signal
voltage being limited by the circuit’s power supply voltage.
DAT Digital Audio Tape, a cassette-based digital recording format.
dB (decibel) a ratio of two voltages or signal levels, expressed by the equation dB=20Log10
(V1/V2). Adding the suffix ‘u’ denotes the ratio is relative to 0.775V RMS.
DI(direct injection) the practice of connecting an electric musical instrument directly to the input of the
/DI Box mixing console, rather than to an amplifier and loudspeaker which is covered by a
microphone feeding the console.
direct output a post fade line level output from the input channel, bypassing the summing
amplifiers, typically for sending to individual tape tracks during recording.
equaliser a device that allows the boosting or cutting of selected bands of frequencies in the
signal path.
fader a linear control providing level adjustment.
feedback the `howling’ sound caused by bringing a microphone too close to a loudspeaker
driven from its amplified signal.
foldback a feed sent back to the artistes via loudspeakers or headphones to enable them to
monitor the sounds they are producing.
frequency response the variation in gain of a device with frequency.
gain the amount of amplication in level of the signal.
headroom the available signal range above the nominal level before clipping occurs.
highpass filter a filter that rejects low frequencies.
impedance balancing a technique used on unbalanced outputs to minimise the effect of hum and
interference when connecting to external balanced inputs.
insert a break point in the signal path to allow the connection of external devices, for
instance signal processors or other mixers at line level signals. Nominal levels can
be anywhere between -10dBu to +6dBu, usually coming from a low impedance
source.
pan (pot) abbreviation of ‘panorama’: controls levels sent to left and right outputs.
peaking the point at which a signal rises to its maximum instantaneous level, before falling
back down again. It can also describe an equaliser response curve affecting only a
band of frequencies, (like on a graphic equaliser), “peaking” at the centre of that
band.