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Peavey Kosmos

Sub-harmonic Generator/Enhancer By Paul White
Published April 2003

Peavey Kosmos

A combined sub-harmonic synthesizer and high-frequency psychoacoustic enhancer for live and studio use.

Perhaps the most famous 'boom box' is the model developed by Dbx to generate sub-harmonics based on the existing low-frequency content shifted down by an octave. But Peavey have now entered the game with Kosmos, which bears the strap line 'Rattle Your Planet' and has a control section named Seismic Activity! Kosmos is actually an enhancer-type device, because, as well as creating bass sub-harmonics, it can also enhance the high end and increase stereo width, so it has a number of potential uses in live sound and in studio mixing.

Peavey Kosmos £249
  • Very easy to use.
  • Adds natural-sounding low end and sub-bass.
  • Can also add high-frequency enhancement.
  • Includes separate subwoofer output and crossover for live and installation applications.
  • HF enhancement could benefit from a frequency control.
Kosmos provides an easy way to add depth to mixes, instruments or individual tracks without making the result sound unnatural.


The documentation claims that Kosmos takes a new approach to sub-harmonic generation that is less 'muddy' sounding than competing systems, and it's also possible to tune the effect to match the speakers you have available. Further to the Quake sub-bass section, there's also the endearingly entitled Thud control that works on the original program material to create more low-end punch around an octave above where the sub-harmonics are being added.

High-end enhancement and stereo width are controlled simultaneously using the Xpanse control, and for live or installation applications there's also a dedicated Subwoofer output with its own Subwoofer Level control, where the crossover frequency is set at 90Hz. This separate output combines the signals from the Quake and Thud processes with any original material that is sifted by the 90Hz filter. When bypass is operated, the Quake and Thud signals are muted as you'd expect, but any original sub-90Hz material is still output from the Subwoofer socket.

The signal path is stereo and fully balanced, with an input gain control that allows the unit to be matched to systems operating at different levels. Green and red LEDs show 0dBu and +10dBu levels respectively, and the maximum output level is +22dBu.

Connection & Setup

The unit follows rackmount tradition, with connections on the rear and knobs on the front. Both jack and XLR connectors are fitted (both balanced) for the inputs and outputs, with a further balanced jack providing the separate mono Subwoofer feed. Power comes in via an IEC socket. Starting from the left, the front-panel controls include a Global Bypass button and an input Level control, after which the majority of the controls are grouped into the Seismic Activity section. Here you'll find a switch to cut the sub-bass from the main output (for when the Subwoofer output is being used) plus a button named Subterranean Shift, which provides two flavours of sub-harmonic tuning to match larger or smaller speakers. The 'in' setting is the deepest.

Peavey Kosmos rear panel.Rear panel.

The Quake control regulates the amount of synthesized sub-harmonics added, while Thud adjusts the level of the punchy low frequencies. For setting bass effects, all you have to do is juggle these two controls until you get something you like the sound of, either for a single instrument or for a full mix. Xpanse looks after the high end and stereo width at the same time, where the minimum setting equates to a flat response. Turning the control is intended to increase clarity and stereo width and is designed to push vocals forward in the mix. Again, just turn it up until you hear something you like, but, as ever, it's wise to check your mix in mono to confirm that the processing hasn't compromised mono compatibility in any way. There are no details on how this section works, but I would imagine that it relies on adding out-of-phase signals to opposite channels, and if this assumption is correct then the worst that will happen in mono is that the effect will partially nullify itself.

Kosmos In Use

The Quake control adjusts the level of the synthesised deep bass harmonics added to the input signal.The Quake control adjusts the level of the synthesised deep bass harmonics added to the input signal.

Most sub-bass devices work acceptably enough on single instruments, but they can sound messy when applied to a whole mix, so that's what I tried first. The best test I could think of was a selection of recordings I made of my own band back in the days of the analogue multitrack. These have been transferred to CD, but are noticeably lacking in depth compared to modern recordings. Kosmos was able to bring about a very dramatic improvement without messing up the basic sound in any obvious way. The secret is to be very sparing with the Quake and Thud controls — just turn them up until the missing frequencies have been replaced and leave it at that if you want a natural sound. I found the least deep Shift position was best for music intended for home hi-fi systems, but of course if you're part of a live reggae band you might want to get the Quake knob replaced with a hexagonal one so that you can get a spanner on it! As expected, Quake adds a very deep sub-harmonic that you can feel as well as hear, while Thud acts more like an equaliser.

The Xpanse control can be quite fierce, and in some ways it would have been nice to have some form of frequency adjustment to enable the effect to be pushed further up the spectrum, but, as with the bass end, if you just add a hint then the high end opens out nicely. Because the width and brightness aspects of the control are linked, I found very little difference in the perceived stereo width at what I considered to be a sensible amount of HF enhancement. I also checked the mono compatibility aspect of this process and found that, although the tonality changed to some extent, the high frequency boost didn't cancel completely.

Listening to the Subwoofer output in isolation enables you to listen more critically to what is being added and, as I expected, the low end sounds quite artificial when monitored in this way, with some obvious artefacts occurring during kick drum beats. However, when the main signal is added, all these side-effects are masked completely, leaving you with the impression of significantly more depth. What's more, the depth aspect of the sound appears to be part of the original, not just an effect that's been layered on, so the overall result is surprisingly natural sounding. Even on isolated drum parts, the effect adds a nice depth to kicks and toms without giving the game away.

Master Of The Universe?

Kosmos is a powerful tool that must be used with care and restraint to keep within the bounds of good taste (and to keep your speaker cones within the bounds of their chassis!), but it does its job extremely well, whether applied to whole mixes or simply to drum tracks and bass lines. If you're working mainly with samples, then you probably won't need it, but if you use real drums and/or bass instruments it could be an advantage, and when it comes to revitalising archive material that is lacking in kick, it's a real life-saver.

Kosmos could also be very useful in a live performance situation, but you'll need a seriously powerful subwoofer to do it justice. I normally shy away from anything that's too gimmicky, but this is a genuinely useful tool for creative sound shaping, remixing, and fixing archive mixed material. If you feel a pressing need to sink to new depths, then you should make a space in your rack for Kosmos.

£249 including VAT.

Peavey Europe +44 (0)1536 461234.