The Sound Guy Spectral Machine Review

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Fig. 1: The control layout for 3 AM, one of Spectral Machine’s general-purpose effects

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Fig. 2: Many of Spectral Machine’s effects offer only a few controls.

New from The Sound Guy is a potpourri of effects—wrapped up in one plug-in—that use Fast Fourier Transform to massage and mangle audio. Flanging, multiband tremolo, equalization and pitch shifting are just the beginning. Other processors virtually transform vocals into keyboard instruments or robots to startling effect. But the biggest eyebrow-raiser is Spectral Machine’s list price: only $49.95.

Spectral Machine supports AU and VST formats. I reviewed Version 1.0.2a of the AU plug-in in MOTU Digital Performer 7.21 using an 8-core Mac Pro running OS 10.6.8.

Navigating Spectral Machine’s user interface is an easy ride. Mouse-click on the GUI’s General Purpose box, and a list of seven polyphonic effects (those capable of processing chords) appears in a browser-like effects menu on the left side of the GUI. (See Fig. 1.) Click on the Monophonic box instead, and the menu lists eight effects that only work with monophonic sources (such as a solo voice or an instrument playing a melody). Select an effect from the menu by clicking on it, and its exclusive control set appears in the center section of the GUI; most of the effects offer very few controls (see Fig. 2). A helpful read-only text field describes the selected effect and what its controls do. A clip indicator and separate sliders for adjusting wet/dry balance and output level are always available on the right side of the GUI.

The Delay Spectral Bands and 3 AM effects each split the audio into three bands; you can adjust the two crossover frequencies for each effect. In Delay Spectral Bands, you can apply separate delay times (up to 10 seconds!) and feedback to each band. 3 AM provides separate depth and rate controls for an LFO controlling each band, creating a multiband tremolo effect.

Spectral Freeze is a 2-band, sample-and-hold effect with adjustable crossover frequency. Click on the Fire button, and the effect samples and plays back a very short slice of the input audio. The audio then decays independently in each band at the rates you set using two sliders. Clicking the Reset button resumes normal play-through of the input signal. The Sample and Hold effect is similar to Spectral Freeze but is wideband, and it automatically and repeatedly resamples the input audio at a time interval that you specify in milliseconds.

Two of the General Purpose effects are simple equalizers. 3-Band Filter is a 3-band graphic equalizer with adjustable crossovers and gain controls for each band. Spectral Peak/Notch is a single-band parametric equalizer capable of producing both bell curves and notch filters. Yet another effect, Oscillating Peak/Notch, lets you modulate the center frequency of a parametric filter with an LFO; depth and rate controls are provided for the oscillator.

Pitch Shift is a single-voice effect that does just what its name implies, purportedly preserving formants in the process. If you need two pitch-shifted voices, select the Harmonize effect; each voice has controls for adjusting its pitch-shift amount, gain and delay. The Spectral Shapeshifter effect shifts only formants and not pitch.

Pitch Quantizer is a chromatic pitch-correction effect with a twist: The setting for its correction control determines the maximum extent to which a note is allowed to move to the nearest semitone. The speed of correction is dictated by the rate slider’s setting. Robotization is another pitch-shifting effect and it’s a brute: It changes any pitch to a single fixed frequency of your choosing, no matter how far-flung it is from the source’s fundamental pitch.

The Pitch Isolate effect strips transients and integral noise (such as the breath noise on a flute track) from audio, leaving only the tonal (sinusoidal) component. Sine/Noise provides two sliders for adjusting the respective levels of transients and noise (together as one component) and the tonal component. With the Vibrato effect, only the pitch of the sinusoidal component of the audio input is modulated; separate rate and depth controls are provided for the LFO.

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Delay Spectral Bands created very interesting, if unnatural-sounding, multiband echoes. I could delay a vocal track’s high, midrange and low bands by different amounts and blend the processed signal with the dry vocal. This took awhile to set up properly as there was no way to sync delay times to Digital Performer’s tempo. And while I could set any band’s delay time to 0 ms (no delay), I couldn’t bypass or independently lower the gain for its output. The result amounted to an arbitrary equalization of the dry signal at the plug-in’s output. I also wish that the wet signal had highpass and lowpass filters at its disposal so that they could be used to siphon rumble out of the low-band delay and make the high-band delay sound more natural. (Highs become progressively dampened in a natural acoustic environment as echo times increase.)

On tracks for vocals and electric guitar alike, Spectral Freeze’s 100-percent wet output created interesting—often bizarre-sounding—drone effects that could be useful to sound designers working on a sci-fi or horror flick. The Sample and Hold effect’s wet output made a vocal track sound like a dynamically filtered keyboard, evoking electronica and dance productions. The inability to sync to Digital Performer’s tempo made it virtually impossible for me to lock the generated notes to my other tracks for more than a bar or two.

I could create outstanding multiband tremolo effects on a synth pad using 3 AM, my favorite offering in Spectral Machine’s arsenal. I only wish the LFO rates for each band could be synched to my DAW’s tempo for faster setup and accuracy. I could also create some good flange effects on electric guitar tracks using Oscillating Peak/Notch.

3-Band Filter and Spectral Peak/Notch were unremarkable equalizers, both in their capabilities and sound quality. Digital Performer’s Masterworks EQ provided far greater flexibility and features.

Pitch Shift and Harmonize were both of limited use. Using either effect, I couldn’t pitch a female vocal up even one semitone without hearing gargly artifacts. Pitching down produced fewer pitch artifacts and preserved formants quite well as long as I shifted the pitch no more than two semitones. Although both effects can be used to generate background harmonies (one harmony in Pitch Shift and two in Harmonize), they must necessarily be parallel; diatonic, or intelligent, harmonization isn’t possible.

Pitch Quantizer was, frankly, a train wreck. Used on a vocal track, even moderate pitch correction—25-percent maximum correction toward the pitch target, at a very slow rate of change—produced a gargly and distorted sound. Equally disappointing was Sine/Noise: Lowering the Noise Gain slider even just a couple dB (to reduce breath noise) made the vocal sound thin, scratchy and distorted. And no amount of formant shifting, however mild, could prevent Spectral Shapeshifter from distorting a vocal track horribly. The wet output for Spectral Machine’s Vibrato effect was also terribly distorted, making it unusable.

Pitch Isolate made a vocal sound like a keyboard instrument with muffled highs, a potentially useful effect in music production. Robotization sounded like Auto-Tune’s Cher effect in your worst nightmare, but I mean that as a compliment. It did such a great job hamstringing the pitch of a singer that she sounded like a computer-generated voice stuck on one pitch. The fidelity wasn’t great, but it didn’t matter. In fact, it made the effect more credible.

Spectral Machine lacks any kind of frequency graph and spectrogram, an oddity and disappointment considering its sole focus is frequency-domain effects. Master controls for multiband parameters would have made setup easier. Also missing are I/O meters, which would help hunt down the origination of unintended distortion. There are also no built-in facilities for naming, saving and loading presets; you’ll need to use your DAW to accomplish those tasks.

Spectral Machine offers several unusual effects that approach greatness for music production and sound design, but others fall far short of professional benchmarks. Unfortunately, the omission of sync-to-host capabilities hampers the use of some of the best-sounding effects—3 AM, Sample and Hold, and Delay Spectral Bands—for music production. Sound designers will especially appreciate Spectral Freeze and, to a lesser degree because it’s a one-trick pony, Robotization.

Considering that Spectral Machine costs only $49.95, you should contemplate giving it a try. The Sound Guy offers a 60-day, unconditional money-back guarantee.


contributing editor Michael Cooper is a mix and mastering engineer based in Oregon.

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