Know What You're Getting
Any time you need to do any recording work or live audio you will need to use a mixer. If you read my articles on how to organise a gig or PA system basics you may find yourself wondering more about mixers. Mixing desks, or sound boards are daunting to look at with their vast array of knobs and switches, but fear not, once you know the layout it all makes perfect sense. I am aware that some mixers have functions that others do not, but there are universal features that all mixers posses and it is these that I am going to focus on in this article. Before you buy a mixer I encourage you to read this as it will give you an idea of functions that you may find desirable which will make your eventual purchase more worthwhile.
Get Something Suitable
What do you want to do with your mixer? This may at first seem a pointless question, as it is obviously to control audio signals. The thing is that different tasks will require fundamentally different styles of mixing console. A DJ will need a mixer that can switch between decks and maybe punch in a microphone for shout outs, while the sound man will need a myriad of controls for flexibility when adapting to new environments. Recording applications will require a large array of channels and equalisation features. Many modern mixers have analogue to digital converters. A/D converters make the audio from the mixer digital so that it can be fed straight into a computer for processing or recording, perhaps both.
Not only are mixers used for professional installations, they can also be utilised in home entertainment systems to give a new degree of control to your various media devices.CD, DVD and Blu Ray players can be connected to mixers so that you can build your audio system around them for ultimate control. This can be particularly useful to those of you who produce media such as digital content for websites or more traditional film/music projects.
All mixers have inputs and outputs, so these are a great place to start. The type of equipment that you need to connect to the mixer will give you an idea of what kind of mixer you will need. Everything that you already own will have its own outputs but don't feel too constrained by them. There will be a cable available that will connect the equipment you have to the mixer but there are a few things you should be thinking about.
Firstly are you dealing with balanced or unbalanced audio and whether it is mono, stereo or something more exotic such as dolby. Mixers that can handle balanced lines will usually be equipped with female XLR connectors for their input. The most common use for this kind of connector is for microphones. Unbalanced audio will usually be input through mono 6mm TS (TS stands for tip sleeve, these are sometimes called "jacks") connectors such as those used for guitar outputs. Headphone connectors are stereo and so they use TRS or tip ring sleeve jacks, some mixers have stereo channels which will take TS or TRS connectors. The opposite is not always true and mono channels may not be able to handle TRS connectors, while others will simply merge the signal and turn the stereo into mono. This is something to look out for when buying a mixer.
DJ mixers used for mixing the signal between record decks Tend to use stereo channels and are usually fitted with RCA connectors. These are the type usually found on home electronics such as DVD players. While limited they can be used imaginatively in certain live situations, such as switching between a stage microphone and a record to achieve an even fade across in a comedy show (I saw a dude do that once).
Beware Phantom Power
Certain equipment will require power to work, a common example of this is condenser microphones. This power is usually supplied directly from the mixer and is called "phantom power". If you are going to be using a variety of microphones, especially for recording make sure that your mixer can deliver phantom power. if it cannot you will be reliant on dynamic microphones or buying devices that will power your microphones. It must be said that some microphones take a battery or phantom power so don't panic if your mixer has no or limited phantom power because you have options.
Alongside the regular audio channels some mixers have a tape in/out channel. This can be useful when you need to connect an audio device for background music in a live situation or if you want to record the signal passing through the mixer. Of course all mixers should have a headphone output so that the signal can be worked in a noisy situation or where attention to detail is needed. Pan controls are also very standard fare and you will do well to avoid mixers that lack even these. There should be an indicator light or series of lights that show you the magnitude of the signal that is in the system. A signal that is too great will sound bad and could damage equipment so it is essential that you can see how much signal you have.. Very small mixers are available that have only a level control and a few channels. These limited devices are useful for small set ups such as karaoke but they may be less than you were hoping for when you want to do more, so avoid them if you are serious about sound. Some very useful mixers are available that are very small but have many functions.
Some digital audio interface devices when coupled with a computer can be set up as a multi featured mixer with some of the powerful features of audio software. This is a technical feat that can be challenging, I will come back to this in the future.
Now we have gone over some of the features that you can expect to find in a mixer you can start to think about which one you want to use. There are so many models out there that you can get one that is suited for your exact situation. Think about your needs and buy according to them.
In part two we will look at how a signal flows through a mixer and how to get a clean mix between some instruments and a microphone. If this sounds daunting then I suggest you read my article on PA system basics to get a perspective on something that can be acheived with this knowledge. My article on how to organise a gig will give you some idea about the advantages of owning your own PA System. My guide that shows how to record using your computer also does this but in a different situation. I have introduced some terms today that may still confound you. I hope that you will check part 2 which is now available. I welcome questions so please feel free to ask if there is something specific that you are looking for. Take care and have fun mixer shopping.