by Jerry Vigil
Using Delays to get a Fatter Sound from Mono Tracks
Whether you're producing a spot, a promo, or an ID of some sort, you'll probably have at least one element that is in mono. In the case of a simple voice-over-music piece, the mono track is the voice. In more complex pieces of production, you might have some sound effects that are mono or possibly some lazer zaps that just don't stand out in the mix. There are several ways to give mono tracks a fatter sound and "spread" them across the stereo mix. Using delays is one way.
Let's take a voice track as our sample, mono source signal. Just about all of the new multi-effect processors offer several stereo delay programs. The most common names of these programs are "stereo echo" and "stereo delay." What these programs do is take a mono source, add two different delays to it, then send one delayed signal to the left output of the processor and the other delayed signal to the right output. These delayed signals can be mixed with the original source material using the "mix" or "balance" function of the processor.
You can use the delay program on voice tracks in two ways: You can set the two delay times and use only the delayed outputs of the processor in your mix, or you can set two delays and mix them with the original, center channel signal. Using only the delayed outputs will give you a wider separation of the voice and will leave the center channel "empty" for the most part. In this case, you would set the left delay to zero and then start increasing the right delay FROM zero until you get the desired amount of left/right separation of the voice. If you don't use enough delay, you'll get a hollow, phasing type of effect. Eventually you will cross that line with the delay time setting that will give you two clean and separate signals.
If you choose to mix the original source with the delayed outputs, you in effect will have three signals to deal with in your stereo mix: the delayed left output of the processor, the delayed right output, and the mono, center channel source material. In this case, since the original, center channel signal has zero delay, you will want to have some delay on both outputs of the processor. You will also want to have DIFFERENT delay times on both outputs of the processor; if the delay times are identical, the two outputs will appear in the center channel and sound like a mono echo. The difference in delay times need only be around 30ms or so, just enough to create the separation. Set your delay times with the mix level of the processor set for full "wet" output. This way you can hear and set the delays without the original voice signal in the center channel. When you get a nice separation of the voice, drop the mix to 100% dry, or full direct signal. Now, begin mixing the delayed outputs of the processor back into the stereo mix slowly until they are just barely present in the mix, just enough to make the voice track sound a little fatter.
Since you only want to slightly change the voice track, you don't want to use very long delays. In fact, 100ms of delay might even be too much. Use your ears and remember that you're only trying to create a "stereo" voice, not a wild, special effect that everyone will notice.
We mentioned that you can use a "stereo echo" program for this effect. You can. The only difference between stereo delay and stereo echo is that the echo program is feeding the outputs of the delays back into the inputs. The amount of "echo" coming from the outputs of the processor can be controlled by adjusting the "regeneration" or "feedback" parameters of the program. If you set this feedback to zero, you won't have stereo echo anymore, just stereo delay.
You don't have to use up two tracks of your multi-track to record this stereo effect, but you can if you want to. On the other hand, if you're short on tracks, you can introduce the effect during your mixdown. Just patch or send the output of the track with the voice into your processor, then send the outputs of the processor to your stereo mix. Be sure to mute the direct output of the voice track if patching doesn't do so itself. If you use "sends" on your console to send the voice track to the processor, use a pre-fader send and leave the fader off.
This effect will work with any other mono source as well. In the case of a mono piece of music, sound effects, or synthesizer zaps, you can increase the delay times considerably more than suggested above without the effect becoming too noticeable.
One thing to watch out for when using the effect on voice tracks: If you concern yourself with what your work sounds like on a mono receiver, punch in and out of mono on your console from time to time to hear how the simulated stereo effect sounds in mono. It has a totally different sound and may not be what you want the listener to hear on a mono receiver.