Using mix bus compression is a process which divides many producers. Whilst some swear by using mix bus compression, others avoid it at all costs.
What is mix bus compression
Mix bus compression refers to the process of passing your mix through a compressor which is inserted on your mix bus. Many producers use this process to add excitement and punch to their songs. By passing the whole mix through a stereo compressor, the tracks can also gain a sense of cohesiveness, glue and polish.
When producers talk about mix bus compression, they are referring to a specific process. That is the process of mixing a song with a compressor in place on the mix bus from the outset. They are not referring to the process of mixing a song and then applying compression to the mix afterwards. By mixing with the compressor in place from the start, you are monitoring the mix through the output of the mix bus compressor. So you can be confident that any level changes you make or any EQ or compression that you apply to individual tracks will sound good whilst being passed through a final layer of compression at the mix bus. Whereas, if you were to mix the track and then add the compression afterwards, you run the risk of altering the balance of the mix that you have made.
The risks of mix bus compression
Whilst mix bus compression has the potential to add a sense of polish and smoothness to your mix, using a mix bus compressor can somewhat decrease the control that you have over things. Your mix bus compressor will compress the loudest parts of your mix most. As such, you could find that the track that you are trying to make the loudest, becomes the part the compressor applies the most compression to. For example, if you try to make the vocals the loudest part of your mix, then as you push the vocal fader up, you are pushing more of the vocal into the compressor. In turn, the compressor will apply more gain reduction to the vocals.
The more familiar you become with mix bus compression, the less of an issue this becomes. But until you become well practiced at the process, it can sometimes seem as though your mix bus compressor is working against you. For many producers, they would rather control dynamic range on a track by track basis. Doing this allows you to keep better control over the various elements of your mix. Whats more, some producers prefer to make their mixing decisions without giving consideration to how it will affect, or be effected by, a mix bus compressor. It is for these reasons that personally, I very rarely use mix bus compression. But that’s not to say that you shouldn’t.
How to use a mix bus compressor
If you are going to use mix bus compression, there are a few guidelines to follow… As previously mentioned, you should mix the track with your mix bus compressor inserted from the outset rather than adding the compression after the track has been mixed. Generally speaking, mix bus compression should be subtle. To achieve this, it’s usually best to start out with a ratio of about 2:1 or 3:1 at most. Slow attack times and fast release times are generally a good starting point. But you will have to experiment to find suitable attack and release times for each individual song.
It’s also important to keep in mind that any changes you make to the mix bus compressor’s settings later on in the mix could potentially affect all of the mixing decisions that you have made up until that point. For this reason, it is beneficial to try and set your mix bus compressor up in a way which will not need altering later. To do this, set the threshold so that the compressor is giving you -1 to -3 dB of gain reduction on the loudest parts of the song. Doing this makes it less likely that you will need to alter the mix bus compressor’s settings later on in the mixing session.
Not sure if mix bus compression is right for you?
There is no right or wrong answer as to whether or not you should use a mix bus compressor. It’s really just a case of personal preference. As with many of the various elements of mixing, if you’re not sure whether or not mix bus compression is right for you, then the best thing to do is try it and find out for yourself. See how you feel about the final results and, just as importantly, see which method of working you prefer. You may enjoy the process of working with a mix bus compressor in place. Or you may prefer to manage the song’s dynamic range on a track by track basis.
Do you use mix bus compression in your songs?