Movin' In Stereo - EMusician

Movin' In Stereo

I’ve always dug that song — probably because I’m a stereo freak! I love it when things fly around the stereo sound field (that is, as long as it’s musically appropriate). So this month, let’s look into various ways to place sounds within the stereo field.
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PAN KNOBS

For stereo placement, many people reach for the pan knob first. While they’re fine for positioning mono tracks, what about stereo tracks? Some musicians will take the left and right outs from a stereo keyboard and pan them hard left and right, and then do the same with the doubled guitar parts, and the drum machine tracks, and background vocal tracks . . . then wonder why their mixes lack clarity. It’s because everything is stacked on top of everything else! Panning parts to the same spot can be useful when you’re trying to blend sounds together, but counterproductive for stereo separation. It’s better to find a separate location in the sound field for various musical parts, and limit how many parts share the same location.

You can use the pan controls to adjust a stereo track’s location in various ways. Narrowing width via panning is relatively easy — instead of panning hard left and right, try setting the pan controls to 50/50, which will narrow the image but still keep it centered in the stereo field. 25/75 will be equally wide, but move the image toward the right. If you pan the keyboard 75/25, the background vocals 25/75, the drum machine 50/50, and the guitars hard left/right, the individual sounds will become much easier to hear than if you just panned them all hard left/right.

ALTERNATIVES TO PANNING

Another way of manipulating stereo track width involves adjusting the relative levels of the left and right channels. Try gradually lowering the volume of a stereo file’s left channel by 6dB, and observe what happens to the stereo image — it should move further to the right as you decrease the left channel level. If your software does not have individually adjustable level controls for the left and right sides of a stereo track, you can usually “split” the stereo track into two mono files. When working with Mid-Side (M-S) stereo tracks, lowering the “side” channels from the bi-directional mic will make the stereo image narrower, until you’re finally left with nothing but the mono signal from the center cardioid mic.

Or, use delays to move the signal further left or right. If you insert a short delay plug-in in a stereo track’s left channel, adjust it for 100% wet (full delayed signal), then set the delay time to 10–20ms or so, the image will appear to come more from the right side. The longer the delay time, the wider the image; but be careful, because at some point longer delays will start to sound like discrete echoes instead of a stereo image.

Short delays can also create pseudo-stereo from a mono source. Either use a mono-to-stereo plug-in and delay only one side, or use an aux send to route the signal from a mono track to a short delay; then, pan the aux return channel to a location other than the original source track’s pan position.

However, it’s vital to check the phase relationship of the straight and delayed signal by occasionally listening in mono. If the sound becomes thin or weak, try a slightly different delay time or hit the phase inverse switch on the delay plug-in’s aux return channel. Other useful plug-ins for creating pseudo-stereo images from mono sound sources include modulation-type processors (such as chorusing or stereo flangers), as well as using different EQ filtering on the left and right channels. For example, copy a track, roll off the highs on one and the lows on the other, then pan them to different locations.

Combinations of these various techniques can work well, too. Figure 1 shows stereo acoustic guitar (tracks 1/2) panned to 75% to narrow the width a bit, along with a short 12ms delay on the right channel (track 2) to move the image to the left a little more. Some plug-ins, such as Voxengo’s Stereo Touch (free from www.voxengo.com), use a combination of delays, EQ, and panning to create pseudo-stereo from mono tracks. Track 3 is a mono background vocal that has a mono-to-stereo instance of this plug-in inserted; the pan controls are set to 25/100 to put the image more toward the right, and thus into a different location in the sound field compared to the acoustic guitar.

Phil O’Keefe is a producer/engineer, and the owner of Sound Sanctuary Recording in Riverside, California. He can be contacted at www.philokeefe.com, or via the Studio Trenches forum at www.harmony-central.com.