Side-chaining in Live using creative sound routing
Side-chaining is a sound routing concept in which the sound level of an audio signal is used to process another audio signal using compression. This is done typically with compressors or limiters. The opposite, however, could also be done with expanders to make the signal louder based on the level of the affecting side signal.
Before compressors had side-chain inputs, engineers could obtain the same result by putting two different signals in the left and right channels of the compressors input but only returning one of the signals back to the board.
One of the most popular side-chaining uses is “ducking”, a process originally used by radio DJs to lower the volume of the music when speaking. The same concept is particularly useful in dance music to get a pumping effect on tracks with hot low end levels. Here long attach and release sounds like pads are configured to duck the kick drum, allowing for the overall volume of the track to be raised. This creates a more punchy sound without adding mud to the overall sound.
There are very few DAW applications that actually allow for proper side-chaining, including Logic, Pro Tools, and Ableton Live. With Live however, you need to have a compressor plugin which can receive audio from two separate stereo channels. There are some commercial plugins out there but if you have a mac your only choice is the “dual comp” plugin which is free but very buggy. The same effect, however, can be done with creative sound routing techniques. The following are two basic examples using Live and the same principals can be applied to other DAW apps.
Stereo side-chain using audio routing
The following illustrates how some creative sound routing can achieve the same output as more commercial DAW software.
Sunday, June 17, 2007
Ducker
Ducker is a tool which I created using iZotope Vinyl. The preset is basically two audio chains used to split the signal then each is panned to its corresponding field. For the side-input, I used the ‘hum’ generated by iZotope Vinyl, which is then modulated in sync to the MIDI clock to create a pulse. The pulse is used on both sides to trigger the compressor on the signal coming in. The pulse is then muted on each channel and the signal is passed through it. Several of the controls from both sides are mapped to macros in order to make changes to the compressor as well as on the pulse quickly and easyily. The result is a totally usable auto ducker perfect for using on 4 on the floor dance tracks and also for introducing rhythmic elements to pads and atmospheric sounds.
Try it out for yourself! Click here to download
Pre-requisite:
iZotope Vynil (download for free from the iZotope website: http://www.izotope.com/products/audio/vinyl/download.asp)
1. Create two tracks. Place a nice pad with a long delay on one and a kick drum for your side signal on the other. Set the audio output of the pad track to “Sends Only”
2. Using a group, split the signal by creating two chains with a utility plugin on each and name them as shown above.
4. Create three more audio tracks and name each of the audio tracks as shown above. Two of the tracks will be used for the left and right signals from the pad while the other will be used to route the side-chain signal. Set the audio outputs of all three audio tracks to “Sends Only” and click on the “Monitor In” button for all three. Lastly, send the left pad output to “Send A” and the right to “Send B”. For the side-chain, pan the audio fully to the Left channel and send the audio to both “Send A” and “Send B” as shown above.
3. Each of the Utility plugins should be set to “Left” channel mode for the left signal, and “Right” channel mode for the right. Set the “Panorama” to 50R on BOTH of the chains. You will end up with all the signal for both chains in the Right channel. No worries- it’s intentional as we will be routing the sound of each chain individually.
5. Set the “Audio From” pulldown to receive the signal from the pad. See picture above. Select the signal from the corresponding chain so that track 2 (L-Pad) receives the signal from the left chain and track 3 (R-Pad) receives the signal from the right chain. Both audio tracks will be receiving audio on the right channel only.
6. The last track is used to route the side-chain signal. Select the “Audio From” from the kick track “Post FX”. The audio will be routed to this track pre-mixer so even if you mute the kick track the side signal track will continue to receive audio from the kick drum. This is useful if you want to mute the side kick while still applying the effect on the pad.
7. Create two “Return” tracks. Pan A all the way to the left and pan B to the right.
8. Drop a compressor plugin followed by a utility plugin into the “Return A” track. Set the utility plugin to “Right” channel mode and the “Panorama” to C (center). Now set your compression levels so that the pad is compressed whenever the kick plays. The settings above should work but it depends on how loud your signals coming in are. Select both plugins and then click on “Group” from the “Edit” menu. Save your group preset.
9. Select the “Return B” track and drop your newly created preset into it. This will ensure that both the setting from A and B are the same. Remember if you tweak one, then you need to apply the same changes to the other or else the resulting signals will not be balanced.
10. You can clean up the session by making the track columns more narrow as shown above, which helps keep things nice and tidy. You can then save this preset and use it as a template for other projects.