these blades will never rust

Mutable Instruments Blades (along with a magnet that’s the front half of a wooden deer, very cute) arrived on Saturday.

Using words to describe the subtleties of sound is kind of a hopeless prospect, and people certainly have their own preferences in filter characteristics just like they prefer different seasonings. There are certain filters whose resonance I really don’t like in anything other than a very small amount, for instance, Korg MS-20 style filters or typical squeaky TB-303 stuff. Some people really hate Steiner-Parker filters, especially Arturia’s “Brute” versions (and those people are wrong.)

To me, when using a single one of Blades’ filters, the words that come to mind are clean, tidy, stable, pleasant. But it’s not boring, partially because of the continuous sweep available on filter modes, so you can tailor the shape to the material. It doesn’t have the “ripping” sound of Ripples under fast modulation, it doesn’t sound like it always has some resonance like Three Sisters, it’s not as sweet and organic as VCFQ. Just considering the sound of a single filter, without the drive — it’s pretty solid, maybe 8.5 out of 10 overall? I sure wouldn’t complain about a synth that had it as its only filter.

But it DOES have that pre-drive/wavefolding stage and it’s got two filters. When you use them together, in parallel or serial or some hybrid, and/or with one modulating the other, it really opens up possibilities. You can get a kind of “shiny” sound with an extra peak, or you can drive it hard serially and get really mean and nasty. This, I believe, is why it’s described as a dual filter rather than a stereo one (though of course it can be used in stereo quite easily).

It pings better than some filters, but not quite as well as VCFQ, or a Hordijk Twin Peak. On the other hand, it resonates very easily too… and it makes for a fantastic complex oscillator.

It has accurate 1V/OCT tracking, and a “shift” button that lets the second filter follow the first with an offset. And crucially, it can do phase modulation, as the three filter modes (lowpass, bandpass, highpass) are shifted 90 degrees relative to each other. Crossfading smoothly between them results in a smooth phase shift (and a minor variation in amplitude). So one can do audio-rate, dynamic phase modulation, with a strikingly different character than Yamaha DX synths. It is also capable of exponential FM too, of course.

There are some downsides to using it this way. None of them are insurmountable, and some present opportities:

  • There are no fine tuning knobs. The range of possible offsets for the second filter makes it tricky to tune to the first exactly. (Workaround: use a DC offset into the second frequency input for finer control.)
  • The relative tuning is not necessarily perfectly stable, and it doesn’t have sync or an automatic ratio lock like some digital complex oscillators. (But you can blend in some of the first filter’s output into the second filter, and it sort of “entrains” into place… not something a more conventional complex oscillator can do!)
  • Since the drive stages come before the filters, you can’t simultaneously use the second filter to modulate the first and then wavefold the result all within Blades. But that’s what other modules are for… and you can do some waveshaping via feedback in ways a conventional oscillator can’t (though some of them will affect the tuning).
  • You do need an external VCA to control the modulation depth. Not a problem.
  • The output is loud, phase modulation increases that level, and it’s enough to clip my ES-6. But I have several ways of dealing with that.

So overall, this is now my favorite filter module!