Destroy FX (DFX) offers an impressive collection of effects plug-ins by programmers Marc Poirier and Tom Murphy. All DFX plug-ins are free, but donations are happily accepted. Most DFX plug-ins are available in VST format for all recent versions of Windows and the Mac OS, and Audio Units versions for Mac OS X are appearing regularly. As the name implies, DFX plug-ins are bent on destruction and plumb the extremes of audio processing. If you're not into mangling your audio beyond recognition but are willing to invest some time learning how these plug-ins really work, you can also achieve some very subtle results. I'll cover three plug-ins in the space provided here. You can find dry and wet versions of MP3 demo files for all of them on the Destroy FX Web site.
Two DFX effects, Buffer Override and Geometer, make essential use of the fact that audio files are read and processed in chunks, often called buffers or frames. Typically, you can set the size of the buffer, which is under the control of the host audio software. Small buffers make for low-latency processing — especially crucial for audio instrument plug-ins. Both DFX plug-ins achieve their effect by overriding the host's buffer settings, and the purpose of Buffer Override in particular is to do just that. Knowing how the buffers are used is key to understanding how the plug-ins work.
Buffer Override is a two-step rebuffering process. You first set a buffer size, which overrides the host's buffer setting; then, you set a Divisor parameter that determines how much of the buffer is played back. In effect, that defines a smaller buffer that loops continuously until the main buffer is refilled. If, for example, the buffer holds a single beat at the current tempo and the Divisor is set to four, the first 16th note of each beat (one quarter of the beat) will play four times before the next beat of audio is moved into the buffer. It can be convenient to set the buffer size relative to song tempo, and that option is provided.
Because the buffer is looped continuously, its size will correspond to pitch if it is very small. To that end, you can use MIDI notes to set the Divisor in semitone increments and MIDI Pitch Bend to modulate it. In addition, Buffer Override provides separate multiwaveform LFOs for modulating the buffer size and the Divisor, and those LFOs can run free or synced to tempo. The MP3 file BO is an example of extreme Buffer Override processing of a simple bass line.
Geometer, the newest DFX effect, is also buffer based. It selects individual points, called Landmarks, in the buffered audio and interpolates between them to create waveforms. The Landmark values and therefore the resulting waveforms change each time the audio buffer refills. Geometer's controls allow you to select how the Landmarks are chosen (for example, at regular intervals, at random intervals, or at zero-crossings and peaks) and how the gaps are filled in (for example, using straight lines, short pulses, or sine-wave segments). Geometer produces interesting results with speech and single-cycle waveforms. With the wrong settings, it can turn just about anything into noise.
Rez Synth is probably my favorite DFX plug-in. It turns virtually any audio material into a playable synth, while retaining some of the sound's original characteristics. Rez Synth works by passing the incoming audio through a bank of bandpass filters whose resonant frequency is controlled by MIDI notes. The bank can have from 1 to 30 filters, and you can set their frequency spacing. Using from five to ten banks spaced in harmonic intervals (major or minor thirds, for example) effectively reprograms the pitch of the incoming audio. The MP3 example RezBrass processes a single-pitch brass loop with pitch controlled by both MIDI notes and Pitch Bend.
Other DFX effects include a dual delay line with feedback and variable playback speed (an effect similar to moving the heads on a tape machine), two gating effects, and a bidirectional scrubbing effect with MIDI-controlled scrub speed. Given that the price is right and the fun factor is high, it's hard to think of a reason not to visit the Destroy FX Web site for a listen.
Overall EM Rating (1 through 5): 4
Destroy FX; Web www.destroyfx.org