How to Buy an Audio Mixer for Recording and Live Sound

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How to Buy an Audio Mixer for Recording and Live Sound

Audio mixers are versatile pieces of sound engineering equipment. They can control the output gain of multiple separate audio signals, and they can be used to add effects and processing to any sound input.
Traditionally, audio mixers were considered specialist items which would rarely be seen outside a professional recording studios or a live music venue. Nowadays, with our technology-driven interests and hobbies, audio mixers are often found in the home too, where they are used by musicians as the hub of a home recording studio.
This guide will outline the most important features of an audio mixer, ensuring it will be suitable for recording purposes, both at home and in the studio, and also as a sound console for live performances. The final part of the guide provides a walk-through that ensures customers will receive value for money whilst shopping online.

What Is an Audio Mixer?

In its most basic form, an audio mixer is a simple device that allows multiple channels of audio to be blended together into one single output. That in itself sounds simple enough, but it is the sheer versatility of audio mixers that can appear overwhelming to anybody unfamiliar with the many uses and features they can offer.
Audio mixers typically conform to a standard configuration. The output level of each channel is operated with a vertical fader, usually across the lower portion of the mixer. Additional controls, such as frequency gain and panning, are located near the top of the mixer. Although the primary function of any mixing device is to alter the volume of each input individually, it will soon become apparent that it is the additional options which make a mixer most suited to recording and live situations.

Using an Audio Mixer

Choosing which audio mixer to buy is a decision primarily informed by its intended usage. Different mixer models are designed with a specific task in mind: from a two-channel cross-fader to a cutting edge mixing console with limitless expansion options.
It is entirely possible to find a mixer that can be used for both recording and live mixing purposes. The secret is to know exactly which features both of these two tasks requires. Then, it is simply a matter of researching the makes and models that offer all of the necessary functions. The table below will offer a broad explanation of what is required from an audio mixer in each situation.

Battle DJ:

Over the years, the technique of Djing – or playing other people's records in an inventive new way – has developed into an art form in its own right. The audio equipment takes the role of instrument, and the audio mixer is an integral part of the live performance. A battle DJ will be constantly adjusting the output of the audio sources. A separate channel is required for each of the turntables (this is usually two, but sometimes as many as four are used at once). Each channel has a fader, and the cross-fader is crucial to the mix. Sensitivity and durability are crucial to prevent live malfunctions. Kill switches are a useful tool that allow the DJ to mix together different elements of separate tracks.

Live Mixing Desk:

An audio mixer intended for live usage will need to be a flexible piece of equipment. Individual bands will rarely expect to use their own mixer, so an in-house console will need to be flexible and offer sufficient functions to cater for any style of performance. As some bands and orchestras will need a large number of microphones, a large number of separate channels will be necessary: usually at least 32 for all except the smallest of venues. Similarly, a sound engineer should look into the number of available bus outputs as these will supply the audio which is fed into the on-stage floor monitors. This signal lets the musicians hear the sound of their own performance above the overall mix.

Home Studio:

A home studio lets musicians make a demonstration version of a new song before recording it in a professional studio. A sound mixer destined for a home studio should provide at least 8 channels of audio. A musician who uses a home studio may require additional features too, such as auxiliary sends and multiple output channels. Auxiliary sends can be used for adding external audio effects to individual channels rather than the whole mix. Additional audio outputs allow the musician to make a recording of the complete mix on an external device such as a tape recorder or laptop computer.

Professional Studio:

Professional recording studios will require an expensive, state-of-the-art mixing desk to offer the most versatile and highest quality recordings. A vast number of channels will be necessary to cater for everything from an individually mic'd drum kit up to a full orchestra. A professional audio mixer will be connected to one, or several, processing racks, which offer signal compression, equalisation, and any number of audio effects. Each channel will require multiple auxiliary sends, bus outputs, frequency gain, and panoramic potentiometers to offer precision control of every element of the final mix.

Key Functions

Below is a table which lists and defines the most common functions of any audio mixer. Understanding how a mixer is operated and some basic terminology, will ensure that the most appropriate mixer is the one that is chosen.

Digital Outputs:

Digital outputs can send audio data directly to a digital recording device via a USB connection. Though a digital output is not essential for either live use or recording purposes, they can be a welcome addition – especially in a home studio where space and finances can limit the options for external recording devices.

Channels:

Audio channels are almost always controlled by vertical faders. The number of available input channels will define the suitability of a mix for each specific task. A two-channel mixer will only be of use for live performances by DJs, for example. A larger number of channels will be required for a whole band or ensemble. Remember: every sound source will require its own separate audio channel.

Cross-fader:

Cross-faders are traditionally horizontal slider controls. They allow one new sound source to fade in, whilst at the same time fading out the original signal at the same rate. Cross-faders are central to all forms of Djing where a continuous output of music is desired.

Bus Outputs:

Bus outputs provide separate audio signals which can be sent to external speakers. Bus signals allow separate parts of the mix to be monitored in real-time: from an individual instrument or effect, to the entire mix. Multiple bus channels will be crucial for any audio mixer used in live performance as the bus signal is what feeds the on-stage floor monitors. Every musician will expect a separate bus output and monitor and rely on the engineer to mix the audio appropriately so that they can hear their own performance.

Auxiliary Sends:

Auxiliary sends provide flexibility to an audio mix. Each send is a pair of input and output sockets, which can be routed to an external processor unit. The output signal is processed by the effects unit then returns to the audio mixer via the input. The sound engineer is then able to blend the original dry signal with the processed wet signal.

Frequency Gain:

Frequency gain controls can be used to boost or cut a certain frequency range (commonly bass, mid, and treble). If frequency gain controls are present, then it is usual for each mixer channel to have separate gain controls. This allows the engineer to combine different sounds evenly.

Finding Audio Mixers on eBay

From the previous two tables it should be more clear which operations will be required from an audio mixer in each situation and also which specific functions can provide them. With the basic technical specifications decided upon; for example, the minimum number of channels and buses or whether auxiliary sends will be necessary, it should be no trouble to find a suitable mixer online.
To save both time and money, it is advisable to shop on eBay. The online marketplace offers listings for items in every category of electronics. As diverse items, mixers may be listed in one of any number of categories on the site. To avoid missing out on a bargain, it is worth searching each category.
For example, mixers found in the TV & Home Audio Accessories and Home Audio & HiFi Separates categories may be intended primarily for home use. But that does not mean they are not more than adequate for other applications, such as for a home studio set-up.
Similarly, looking in the Other Accessories/ Equipment subsection of the Musical Instruments category may allow you to find audio mixers that could be perfect for use in a small music venue. Lastly, the Mixers category will display every device on eBay, from a basic DJing unit to the highest-specification professional mixing consoles.
Finally, it is possible that some mixers will be included in the eBay Deals listings. Large cost savings can be made on these items, so it is always a good idea to check.
Conclusion

There is no single audio mixer that can provide excellent performance in every circumstance. Knowing what will be required of a mixer and which functions will meet those requirements is key to selecting the most appropriate model. Getting value for money is a matter of researching and comparing similar items. With the information provided in this guide, it should be no problem to find the perfect audio mixer on eBay.

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