31
AUDIO MIXER function
Overview
The HS-600 has a simple, cost effective, four channel analogue audio mixer built in. The HS-600 has the ability to
take audio from several types of analogue audio sources.
To achieve a good audio mix for recording or transmission it helps to understand which audio connections and
settings are best suited to a particular type of audio source. In fact, it may even help prevent damage to your
equipment, your hearing and even protect the audio circuits of the HS-600. So if you are new to audio mixing this
information should be very useful.
The audio is fed into the mixer on the rear panel using the connections as shown below.
Line level and Mic level
Audio signals are fed into the HS-600
’s audio mixer on standard analogue audio cabling and connections.
Depending on the audio source, cable type and settings used these audio source signals can be received by the
HS-600 at different levels, typically Line level or Mic (microphone) level. This could be an issue because audio
signals which are either too low or too high can ruin an otherwise professional video production or recording.
The main cause of different audio levels being input is usually the source equipment being used. A microphone, a
CD player, a musical instrument, a DVD player and even a P.A. system can all supply different default audio signal
levels. So knowing which sources supply stronger or weaker audio signals can help you avoid problems.
Typically the industry uses the
Decibel
, noted as two letters
dB
, to describe or measure the audio signal level
being supplied by any piece of audio equipment or instrument. Depending on the type of equipment being used the
letters dB may also be followed by a further letter indicating which scale or method of measurement was used to
rate the signal. Yes, to confuse matters audio levels can be rated or defined using different methods. Luckily, there
is an easy way to decide which items of kit should supply the lowest and highest signal levels.
Microphones
- Typically supply the lowest audio signal levels, especially if they are non-powered microphones.
There are exceptions to this but as a general rule most microphones will have to be pre-amplified to a higher signal
level before their audio can be mixed alongside other audio sources. The HS-600 has two mic pre-amp circuits.
Musical Instruments
– Such as keyboards and guitars supply higher than microphone signal levels but may still
need to be pre-amplified correctly before their audio can be mixed alongside other audio sources. Audio cabling
used incorrectly can also a
ffect the ‘sound envelope’ of an instrument but we will not go into that here!
Equipment with RCA or Phono Connectors
– Such as CD players and DVD players will supply audio at an
industry agreed ‘default’ line level as there is usually no way to adjust the audio signal level going out of the
equipment. Typically this ‘Line level’ audio is considered to be for delivery to other consumer type equipment such
as a television set or Hi-Fi equipment, which will then control the audio heard at any attached speakers. As such
this line level (-10dB) is usually much higher than a microphone level and slightly higher than a musical instrument
signal level.
Equipment with balanced XLR 3 pin connectors
– Such as professional audio mixers, recorders, players and
amplifiers will supply audio at an industry agreed line level too. The main difference here is the professional line
level can be as much as 30dB higher than the consumer rated RCA type line level connection from say a DVD
player. That can be very loud and even ear damaging if you are not careful.
SAFETY FIRST:
Always connect any audio connections with the equipment powered off and set the audio mixer
faders or any headset volume knobs to minimum. Then turn on the equipment before slowly raising the audio
faders or headset volume to a desired comfortable level.
