If you are not familiar with buss processing it is simply a technique that involves processing an entire group (or buss) of instruments at once. This could be two guitars, fifteen drum parts or an entire multi tracked mix.
For a concept that is so simple the end result shouldn't be that profound, but in fact it is. The effect that this sort of processing has on groups of instruments is pretty exceptional and it's a hugely useful tool for anyone looking to take their mixes to the next level.
As I pointed out in the introduction buss processing can really be applied to just about any group of instruments, and in a way the ultimate buss processing would take place on your master buss. In this case I thought I would demonstrate the process on something just as important ... Drums.
Sometimes even the best mixed drum parts can sound a little divorced and separated. Often treating these parts as a whole and applying a few select effect processing across the board can really add a certain cohesion to proceedings.
The first thing you need to do is select all the parts you want to process, in my case this is a selection of drum loops. I am using a combination of Logic and Cubase to demonstrate my point here, but of course this is a totally generic technique and can be performed in any DAW.
Audio: The dry untreated drums:
Once all your parts are selected you will need to feed them to a group. The exact technique here will obviously vary DAW to DAW but it's usually a pretty straight forward process.
With all your sounds being fed to one dry group make sure that your gain structure is sound and that nothing is clipping. Your group should have plenty or workable headroom and this will mean running your individual channels a little lower than you usually would.
The first processes I tend to associate with drum groups are equalization and dynamics control. If you feel your overall drum sound lacks a little sparkle or low end punch then applying EQ to the whole group can work wonders.
For some reason this tends to have a much more positive effect than adding more EQ to each individual sound. The result is generally more organic and less hyped. If you want the outcome to be warm and gritty try a vintage emulation EQ, if you prefer clean and sparkly go for a linear phase model.
Compression is a another key tool when it comes to processing any buss, not just drums. Add an emulation of a vintage compressor to an instrument group and something almost magical happens. A special type of audio glue is applied using this process and often it can create the illusion that these instruments were always together!
Buss compression works especially well when it comes to drums and although stock plug-ins from Logic, Cubase or Pro Tools will work just fine you may be better off using for a third party product here. There are some truly awesome software based buss compressors out there.
Personal favorites of mine include the UAD or Waves SSL buss compressor models. These deceptively simple looking plug-ins don't need much more than a quick tweak to impart a really impressive cohesion to your groups.
Audio: The drums are treated with compression and EQ:
Equalization and compression are essential tools here but if you feel you want to try something a little more edgy then you could do worse than experimenting with a few saturation plug-ins.
Saturation, or 'soft clipping' can add a warmth or fatness to your groups that's synonymous with classic tape recordings or tube driven signal paths. Again, there are plenty of decent saturation plug-ins bundled with DAWs but you might want to delve into your pockets and invest in high end products to get the best there is.
I find that the really simple plug-ins work very well here and one that I keep going back to is the URS 'saturation' plug-in. It does exactly what it says on the tin and get's the job done. There are more complex models out there like the classic PSP Vintage Warmer or the Voxengo Varisaturator.
The Vintage warmer is a great saturation plug-in
Once all this processing has been applied you should find that you've got a pretty even signal with well behaved dynamics, but if you still have peaks in the overall level you can apply a final limiter to the group.
If you plan to apply this safeguard it should be right at the end of your chain and you should really avoid pushing it too hard. You want to preserve as much of the signal's original dynamics as possible.
This technique is not for everyone as it does make your mix a little 'hotter' so it's worth experimenting with it to see if it works for you and your project.
Audio: The drums with some saturation and limiting:
When we start to use buss processing and group similar instruments in a mix, getting our relative levels at the mix down stage suddenly becomes a refreshingly straight forward task. It's simply a case of mixing seven or eight sub groups as opposed to thirty or forty individual stems.
This style of mixing is great and saves a huge amount of time and ultimately gives you a better sound, but what happens when you want to automate the level of... let's say your drum group? Now this would normally be fine but if you decide you want to change the relative level of the drum group it will just snap back to it's automated level.
Master groups in Logic's Mixer
The solution here is a second 'master' group. This allows you to control the level of an automated group without applying any further processing or impeding the signal in any way. A nice simple trick and extremely easy to set up.
Buss Processing is just one technique to help make your mixes better. Find out direct from the Pro's how they Mix their tracks in Mixing R n B in Logic, Mixing Pop in Pro Tools and Sonic Dimension in Mixing.