A Different Drummer

Jun 1, 2007 12:00 PM, By Len Sasso

Using vocoders for nonvocal purposes is nothing new. Of the vocoder's two inputs, the carrier needs to have sustained notes with rich timbre. The speech input, which is used to shape the carrier, needs to be rhythmic and have quick changes in timbre. As an alternative to speech, the percussive and unpitched nature of drums makes them especially well suited to the task.

Full drum tracks, however, don't make the best vocoding sources; tailoring a drum part specifically for vocoding will produce more-interesting results. In this column, I'll describe how to build a Combinator based on Propellerhead Reason's BV512 Vocoder and Redrum modules to use as a general-purpose drum-vocoding effect (you'll find the Combinator and several Reason songs illustrating it in Web Clip 1 ).

Combinatrix

Start by creating a new Combinator, which will automatically be cabled into your song's main mixer. Inside the Combinator create a Line Mixer, two Spider Audio modules (Spiders), a BV512 Vocoder, and a Redrum. Hold down the Shift key when creating these modules to prevent automatic cabling. Rename the two Spiders as Carrier and Speech.

Cable the Combinator's To Devices output to the Carrier Spider's Splitter input. Cable one of the Carrier Spider's Splitter outputs to channel 1 of the Line Mixer and cable another to the BV512's Carrier input.

Cable the Redrum output to the Speech Spider's Splitter input. Cable one of the Speech Spider's Splitter outputs to channel 2 of the Line Mixer. Cable both channels of another of its Splitter outputs to the left channel of its Merger input; that sums the Redrum outputs to a mono signal; cable the left Merger output to the BV512's Modulator input. Finally, cable the BV512's output to channel 3 of the Line Mixer and cable the output of the Line Mixer to the Combinator's From Devices input. I call this Combinator a Drumcoder.

I like to program the left two Drumcoder buttons to quickly solo the carrier and drums. Both buttons should solo channel 3 (the BV512) of the Line Mixer. The carrier-solo button should also toggle the BV512's Enabled switch between 1 and 0. The drums-solo button should also toggle the BV512's Dry/Wet control between 127 and 0 (see Fig. 1).

Care and Feeding

Reason sees the Drumcoder as an effects device. To use it, load a Reason module that produces a pad or ambient sound. It will automatically be cabled to the Drumcoder's Combi Input to become the carrier.

You could load a whole kit into Redrum, but you'll get better results choosing individual drum sounds based on their vocoding effect. Try standard drum sounds as well as sound effects. When you have some or all of the channels filled, move on to building patterns.

You can add interest to the Drumcoder in several ways. Insert a compressor with a high compression ratio between the Redrum and the BV512. Insert a long-tailed reverb in the Line Mixer's Aux bus and set the bus to prefader. Raising the carrier channel's send level will then add a hint of carrier without dominating the mix. Feed a pair of delay lines from the Redrum's Send outputs and use the Speech Spider to add their outputs to the BV512's Modulator input. Then, using different delay times, send some individual drum channels to each delay line.

I assign the Combinator knobs to the Line Mixer's Aux return, individual delay times, and the combined feedback of both delays. I assign a button to simultaneously enable both delays and another button to toggle the BV512 between 8- and 16-band operation. Consider using the LFO output of a Malstrom or Subtractor to modulate the Combinator knobs.

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Len Sasso is an associate editor of EM. For an earful, visit his Web site at www.swiftkick.com.