Microphone preamps
The signal that a microphone outputs is a very low level signal. In order for any equipment to process this signal it needs to be boosted to line level.
This is basically what a preamp does. The preamps on your mixer should have an accurate gain control, possibly a trim control, a pad and phantom power.
- Gain control - This is the main control of a preamp, it is what selects the sensitivity of the preamp, and should be set carefully to maintain the correct gain structure throughout your system
- Trim control - This is a fine adjustment of the gain control, not all preamps have this, and it is not vital, but it is a nice additional feature to have if available.
- Pad - A pad button is provided on most preamps to accommodate high volume sound sources. These circuits are preset to attenuate the preamp usually by 10/20dB.
- Phantom Power - Phantom power is used to charge the plates of all condenser microphones. It should be available on all microphone inputs, but is sometimes switched on/off in banks of 8/16
It is always a good idea to use the best quality microphone preamps you can afford, they are the first link in your recording chain, and are vital to capturing a detailed and full sound.
Inserts
Inserts are the next step in the signal path of most recording mixing consoles.
As their name suggests they are way to INSERT extra equipment into the signal path of your mixer channel.
Inserts are great for re-routing mixer channels through external compressors, EQ's gates etc.
Auxiliaries (Aux's/Cue's)
The auxiliaries on a mixer are a way to send a COPY of the mixers channel to an effects unit, or other external equipment.
It is important to remember that although a copy of the signal is being sent to another piece of equipment the original signal is still sent through the channel unaffected. This makes them ideal for adding effects to channels as the same effects unit can be used on multiple channels simultaneously.
EQ (Equalizer)
EQ is a means of affecting the tone of a recorded sound by boosting or cutting certain frequencies that are present in the original sound.
By using varying amounts of boost/cut at particular frequencies the tone of a sound can be dramatically affected.
This is vital for mixing, and is one of the most powerful tools available to the recording engineer.
EQ is usually integrated into most mixers, but external units are available, at a vast range of prices from $70 right up to $7,000+.
Subgroups
Subgroups are a way to group a series of channels of a mixer together, to allow the volume and tone of them all to be affected simultaneously.
Subgroups usually have their own insert points, and some have matrix's (Auxiliaries for subgroups).
For example, it is very useful to subgroup all drums channels (kick, snare, hats, toms, overheads etc) so that the same mix of the channels can easily be faded in/out, muted or even EQ'd or compressed.
Faders
They may seem simple but the faders on your mixing console are one of the most important tools available.
A good, well designed fader will allow accurate control over the level of the sound on that particular channel. Bad faders tend to be inaccurate, noisy and do not 'feel' responsive.