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Besides microphones, there are other instruments we would require during a production. They are audio faders, mixers, and audio connectors. Let us discuss them briefly.
Audio Faders
Faders are instruments, shown in Fig. 7.10, that are available on all cameras and recording instruments. Exclusive audio faders are available in the market. They enable the sound recordist to increase or decrease the level of audio being recorded on the recording medium. They function like volume controls on our TV sets. It is important to set the fader at the optimum level to ensure the best quality sound. For example, in video cameras, ensure that the recording level does not cross 12 dB on the recording level. Audio recorded consistently beyond 12 dB will have a 'crack' effect and sound very distorted. The indicator on the fader levels of an audio mixer has two sections-the green and the red light emitting devices (LEDs). The series of green LEDs indicate whether the audio levels are well in control. When the audio levels consistently shoot beyond the green LEDs, the red LEDs light up. The red constants lighting up of LEDs indicates a problem with the audio.
Audio Mixers
Audio mixers (Fig. 7.11) are instruments that are more complex than the audio faders. The complexity is also a boon since they help us perform the following functions: 
- Control the volume of signals coming from various inputs (microphones, audio players, etc.-l using faders. The faders help in regulating the input levels of sound sources coming from various sources (mics or audio players).
- Combine and balance the inputs coming from various sources, while using one fader up or the other down. For example, in an audio mixer with six inputs, we connect six microphones to record a musical score. Fading up or down each fader helps in balancing the input of each instrument.
- Equalise, that is, manipulate the characteristics of input sound. Equalising involves controlling the audio signal by increasing some wanted frequencies and decreasing the unwanted ones. For example, you can reduce the hiss in speech by equalising the input.
- Auxiliary send is used to send the output to other external devices such as an effects generator. The output from the Aux Send is again taken back into the audio mixer, mixed and routed through the final output.
- Route the mixed and equalised audio signals to a specific output (recorder/speaker /headphone).
- Enable monitoring of all the functions mentioned above through speakers/headphones as they are being recorded/broadcast.
Audio mixers are known by the number of inputs and outputs they provide. For instance, a 6 x 2 audio mixer has six inputs and two outputs. Similarly, a 24 x 4 audio mixer has 24 inputs and four outputs. This means that you can connect 24 microphones/players, balance, and equalise those inputs to get four outputs.
Audio mixers come in handy both in live and post-production situations. In a live situation, audio inputs are first balanced and equalised and the recording done. In post-production situations, an audio mixer is used on linear editing suites (non-linear suites have built-in audio mixers). Inputs/ outputs have to be manually adjusted for balance and equalisation. You will learn more about it when we discuss editing.
Professional audio mixers have a provision to connect a headphone or a pair of speakers to monitor the output. Some audio mixers are also capable of providing the phantom power supply to microphones when needed. It is always better to purchase audio mixers that can provide phantom power supply.
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