Sonic LAB: DSM01 Curtis Filter Eurorack Module

Exciting news when a major synthesizer maker announces and intent to create Eurorack modules, and Dave Smith Instruments certainly got the community talking.

The DSM01 is a Curtis filter - a flavour of filter that has been found in many  (if not all) Dave Smith designed synths since the Sequential Circuits days. Dont expect a true vintage filter though, these are most likely the  type made for Dave's current synths.

It's a 2/4 pole switchable Low Pass filter. It's always tricky to completely describe the sound, but I'll have a go - the character is bright, brassy and brash. I don't think I'd be far out of line by saying that it's not unlike the Pro One.

The module is 8HP - two wide essentially, controls are Cutoff Freq, Resonance, -12dB/-24dB switch (2/4 pole),boost switch - this drives the filter harder for a more, well driven sound.

Inputs and Outputs

Cutoff CV Resonance CV VCA CV - thats right, there's a VCA on board as well, indeed there are two outputs - VCF -pre VCA and VCA out post VCF and VCA.

It's a nice additional feature, anything that adds function in a small unit is most welcome, though you will need to send it a full 10v to match the level of the VCF output.

The Sound

In 4-pole (24dB) mode, it has a very familiar character, sending in a low Sawtooth gives that pleasing, brassy quality, as I said, I don't think I'm out of order saying it has a Pro-One quality to it. Dialing in resonance does result in a significant bass roll-off but that's the nature of the Curtis filter sound, it will scream and self-oscillate, making it entirely playable. Adding the drive switch really boosts the signal, adding that warmer smudge you'd expect.

In 2-pole mode, the resonance almost entirely disappears, almost giving a hi-pass quality to it. Not at all unpleasant and certainly with uses.

Controlling the VCF and resonance separately can give some really interesting tonal modulation possibilities, and when you add the VCA input into that, you've got a world of options there. I did find that the VCA output was significantly quieter on my system, I suspect that it's because I was not sending a full 10v (maximum) control voltage. DSI tell me that the VCA will match the VCF output when fully 'on'.

So Would I?

Short answer, yes I would, at $179 / £120 ish it's not an expensive option and known quantity  of the Curtis sound is not to be sniffed at. No, it's not as characterful as some other dedicated filters, but I personally do like the sound, so would find a space in my system for it.

Becoming available now at all good modular outlets.

More Information

• DaveSmithInstruments.com

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