You know the world is all askew when Expert Sleepers—best known for its multi-faceted Disting module as well as their various tech-to-modular/modular-to-tech interfaces—goes all hippie on us and comes out with a line of 100% all analogue OTA [Operational Transconductance Amplifiers]-based modules. Lucky for all us “squares,” there’s no need to grow our hair long, wear drab-colored robes [nothing against that, BTW, who am I to judge?], or follow some noodly guitar band around to appreciate Loralei, Beatrix, and Ivo, the modules that we’re talking about here.
The three modules definitely point to another era, due to their names, which stem from the first three tracks off the Cocteau Twins classic album Treasure [though my favorite by them is Heaven or Las Vegas and it still hurts when I hear it—bad breakup, don’t ask]. Beatrix, Lorelei, and Ivo all don the signature Expert Sleepers classic black faceplate and sturdy build, and are sure to free up Distings all across the globe for those pining for an ES only rig.
First up is Lorelei, a quadrature sine outputting VCO, with waveshaping, and sync/cross-modulation options. There are CV inputs for 1V/Oct, Linear FM, Exponential FM [with attenuator], X-mod, and Shape [with attenuator], and three waveform outputs: Square/pulse, Sine/pseudo-triangle, and Cosine/pseudo-saw. The waveshaping controls on Loralei affect all three wave outputs equally, and there are also knob controls for Octave, Tune, and Shape [on top of the aforementioned attenuation controls], to round out the Ins, Outs, and controls for Lorelei.
The knob controllers are pretty self-explanatory, though the Octave pot is a little different as it’s an endless encoder, which is pretty strange since typically an oscillator will have maybe 8 octaves, so there are 8 options for the octave ranges, and therefore an endless control wouldn’t seem like a sensible choice. Well, Loralei has an 8 octave span, but there are empty slots on the encoder that repeat those octaves in a clockwise manner. The manual doesn’t address this at all, and like I mentioned, it is a little strange, but this makes the Octave control pretty playable; and while it’s not a make-or-break addition to the module, it’s a nice feature that doesn’t take up any extra space.
The Shape control morphs the bottom wave outputs from sine to triangle-ish on the second output, or sine to saw-ish on the third waveform and alters the pulse width of the square wave output. Again, this has a CV input and you’re able to fine tune the amount you’d like with the attenuator.
The X-Mod input is basically a sync in, though it gets more eccentric than most, and is pretty fun to play with, as is Loralei as a whole.
I really like having the three outputs and the ability to morph the shapes, as well as the endless encoder for the Octave select. You can get some really great sounds out of Loralei and the feature set and overall quality of this module really outpaces the price of it.
Next up is Ivo, a resonant low-pass VCF switchable between 2 and 3 poles [12dB/octave and 18dB/octave, respectively] that pairs extremely well with Loralei [who would have thunk?] due to the fact that it has two inputs, one with an Input Level attenuator, so you can mix two signals into the filter input, a nice feature to have onboard. And who has a few waveform outputs that you can throw into Ivo’s inputs? [Hint: See above]. Above the inputs, there are two CV Cutoff inputs for modulation [one with an attenuator], a Feedback CV in, and there are also controls for each the Feedback and Cutoff.
Like the other two modules in the series [this is a series, right?] this is OTA-based, and in terms of filters what this means is that it usually has a smooth sound, as compared to say, a Moog ladder style filter, and Ivo is definitely excellent sounding and pretty clean. Which doesn’t mean it can’t scream, too; it howls with the best of them and using the first Cutoff input Ivo tracks pretty well. If you throw some CV into the Feedback input Ivo perks up even more and is a very serviceable sound source. I actually found myself using it a lot as an oscillator as well as a filter, but it sounds great as both.
Lastly, we’ve got Beatrix, a phaser that has the same analogue/OTA build as Loralei and Ivo.
Beatrix has more controls than the previously mentioned modules, with inputs for Frequency CV [with attenuator], Offset, Depth, and Feedback, as well as one Input and one Output. There are also switches to disable the phase, thereby turning Beatrix into a resonant filter [we’ll talk a little bit more about that], and a Sum switch to invert the filtered signal for another sound option. There are also controls for Frequency [which tracks at about 1V/octave], Feedback, Depth, and Input level.
Beatrix lets you control the notch frequencies, the resonance and how deep the phaser affects your sound, and it also has the Offset input that lets you sweep the filter notches without touching the resonant frequency, something that looks really cool when viewed through an oscilloscope.
The manual states that Beatrix can self-oscillate at high feedback, but in order to do this you need to get out your microscopic screwdriver to modify the factory settings. This brings me to something about these modules I’ve been pontificating on: Self-modulating Ivo will turn it into a very usable sound source as an ad hoc oscillator; switching off the “phase” switch on Beatrix essentially turns it into a resonant filter; doing this and increasing the feedback [with a little under the hood tweaking] will get Beatrix to self-oscillate, also turning it into a sound source...I’m always explaining to non-synthesists how closely the myriad of confusing terms and modules are related [gate, trigger, clock…] and this is another great example of that. I probably do more damage than good when trying to explain, so it’s very helpful to have real world examples of easily demonstrable modules to help indoctrinate the unindoctrinated. What’s also interesting about this in terms of a psychological profile type of study, is Expert Sleepers inclination—and ability—to make modules [a-lá the Disting] so versatile and multi-functional. It’s like they can’t help themselves, they have to pack as much into as little as possible—digital or otherwise—and maybe that’s what all this 100% analogue OTA laced—I mean, based—trip is all about. Being true to one’s self and going back to one’s roots while paying homage to an amazing album.

Lorelei
8 HP +12v 55mA -12v 54mA
Price: $ 185
Ivo
8 HP +12v 22mA -12v 18mA
Price: $ 185
Beatrix
8 HP +12v 22mA -12v 21mA
Price: $ 185

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