Peavey Kosmos Pro Sub Harmonic Enhancer

By Barry Rudolph

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Mix Magazine "Compression And Compressors"


Peavey Kosmos Pro Kosmos Pro® is an expanded version of Peavey's original Kosmos subharmonic enhancement system. Now with +4dB electronically balanced XLR I/Os and S/PDIF digital I/O, Kosmos Pro makes its entrée as a truly professional all-analog unit with control over four processes: a subharmonic synthesizer called Quake™; Thud®, a low-frequency "sculpture" tool; a high-frequency and stereo image enhancer named Xpanse®; and Stratos, a dynamic HF effect. I tried Kosmos Pro on drums, bass, guitars and full mixes with excellent results--results not achievable by any combination of existing analog processors.


Internal construction is good with surface-mount components, a THAT VCA chip for dynamics processing, internal AC power supply and a Crystal Semiconductor chip set for the S/PDIF I/O. The S/PDIF I/O parallels the analog connections and locks to incoming digital feeds up to 48 kHz.

Front-panel controls include a Global Bypass button, a switchable LED meter and two input/output level pots (center detented at unity gain). The pots feel a bit flimsy, but are noise-free and work well. Each provides up to 10 dB of extra output level. A Cut Sub-Bass From Main button splits all LF enhancements from the stereo output and routes it to a mono subwoofer jack (1/4-inch TRS). This feature separates a stereo signal's normal bass content for recording just the subharmonic effect to a separate track. This output is distortion-free, with plenty of level and wide dynamics.

Most of the other names for the front panel controls on Kosmos Pro are unique. They have geological names and adjust many internal parameters simultaneously to produce a given result--typical nomenclature doesn't apply. When any of the four processors knobs are fully CCW, its effect is bypassed--a good design feature allowing you to use any amount and combination of one or more process.


The Quake control sets the level of a synthesized bass signal one octave lower than the input source. This signal tracks the input dynamically and operates within a defined range, up to about 100 Hz. The active LED indicates the presence of usable source information. Quake works well on kick drums, tom-tom tracks, and overhead and room mics. I connected the unit on a stereo send and return as I would a reverb, so that I could set different amounts on a multitracked drum kit. With this unit in your rack, there is no excuse for thin-sounding kicks and toms. I especially liked pumping up the low end of drum room mics. On bass and acoustic guitars or any musical instrument, in my opinion, adding a sub octave is a musical decision and in this case, Kosmos is the best 'octave divider' I've ever heard! Kosmos offers good, clean subharmonics: There is no mistracking, and it is quiet and clean.

The Dynamics control could be thought of as a damping adjustment that controls the envelope release time of the synthesized Quake signal. You can go from a tight, fast-responding subsonic signal to a looser, boomier-sounding effect. On kick drum, I adjusted the sub note's "hang time" with Dynamics. On a solo acoustic guitar, using Quake with longer Dynamic settings is like adding a bass player: Every time my guitar player made a percussive thump, an octave-lower note was produced. Sub-Terranean Shift™ alters the center frequency of the synthesized sub harmonic information. A subtle difference when listening on full-range speakers, the Out position is a higher center frequency the manual says is better for smaller speakers with the In position lower for bigger speakers.

Thud is like a multiband compressor that tracks the input signal and dynamically boosts a band of frequencies from 100 Hz to 350 Hz. It operates at roughly an octave above Quake's output (i.e., the source's original octave). Both Quake and Thud processors' outputs are phase-coherent. Thud was useful on a thin-sounding acoustic guitar track when adding an octave wasn't appropriate. Thud acts like a dynamic bass EQ and is good for instruments and vocals. The Deeper button changes the center frequency range of Thud to narrow the frequency difference between it and Quake.

Xpanse is a collection of stereo filters that dynamically modulates phase, time and frequency domains. However, according to Peavey's Lloyd Trammell, "The phase shift angle of the left/right channels does not change by the same amount; it may be a +3 degree shift on the left, while the right has a -7 degree shift. It depends on the input signal's frequency content and amplitude." The Barometrics knob controls the range of frequencies that Xpanse works on. At the counterclockwise Dense position, it works on the widest range for maximum phase manipulation, while at the clockwise Thin setting, Xpanse acts on a much smaller range with less phase manipulation, sounding more like a special high-end boost.

I tried Xpanse on an acoustic guitar recorded with two mics on two tracks. Normally, when these two tracks are panned hard left/right, this recording sounds like a wide mono guitar track. Using Xpanse produced a wide stereophonic effect, and when collapsed down to mono, it revealed some phase cancellation, mostly a small reduction of low frequencies.

On bass guitar recorded on two tracks (DI and amp), Xpanse produced a stereo bass, with a superwide footprint that you have to hear to believe. Xpanse also works well on drum overheads or most stereo pairs, throwing the left/right channels outside the edges of the speakers. Meanwhile, turning the Barometrics knob toward Thin brightened everything, reducing the width.

Stratos adds high frequencies above Xpanse's range, using modified TransTube® technology from Peavey's guitar amp line. Stratos is a pleasant-sounding, superhigh "air" EQ that was especially useful on acoustic guitar tracks. Stratos is also dynamic, so there's little boost in track hiss and noise, like a regular EQ would have added.

The final control is Sub-woofer, a level control where the outputs of Quake, Thud and the source's original low frequency (from a 90Hz cross-under filter) are summed to the Sub-woofer 1/4-inch TRS output jack.

Far from a 'one-trick pony' effect, Kosmos Pro is a valuable recording, mixing and live sound tool with four unique and easy to use processors. I found the unit remarkable for adding a special low frequency signature to most any source. Impossible to duplicate and, at the $599 MSRP, that would be more than enough but the additional Xpanse and Stratos high frequency effects just add icing to this cake unit!

Peavey Electronics, 601-483-5365,

Barry Rudolph is an L.A.-based recording engineer. Visit his Web site at: WWW.BARRYRUDOLPH.COM

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