A comparison of two frequency shifters: the Cwejman FSH-1 and Synthesis Technology E560 'Deflector Shield'.
Two 'Klangumwandler': one analogue, one digital. One is capable of wide shifts, the other of going thru-zero.
To kick things off, here's a multi-tracked recording featuring both:
Download the album for €1 or more to access the examples.
Internal make-up aside, the key difference between the Cwejman and Synthesis Technology modules is the range of available shift. The FSH-1 is quoted as spanning 0.02Hz to 12kHz. The E560 concentrates on lower frequencies to take advantage of the stereo effects made possible by shifting thru-zero.
Take care of your ears and speakers with these recordings!
Here's a quick manual tweak of the frequency.
(range, MMF-1 sine. FSH-1, then E560).
While the Cwejman has a switch to toggle between LFO and audio rates and a fine tune dial, the SynthTech relies on a single frequency knob with a highly-exponential response. This makes it easier to dial-in slower rates, but, as you can hear, the jump in the last 10 degrees of the pot's rotation makes it harder to set higher frequencies.
Unlike the FSH-1, the E560 is capable of thru-zero shifts, offering enhanced stereo images. Modulated with a bi-polar CV, the up & down shifts swap sides; what's up, goes down and vice versa:
(e560_thruzero, MMF-1 sine. E560, manual tweak, carrier 8).
Due to it's highly exponential response and clamped range, the E560 seems happiest at slow rates, producing lush tremolo effects. Here's an example, isolated from the first recording:
(e560_slow, RES-4. E560 carrier wave changed near end).
By contrast, the FSH-1 will track higher changes:
(hitrack, MMF-1 sine, CV to FSH-1 then E560).
This opens up timbral possibilities which, given a suitable offset, can sound similar to linear FM:
(fsh-1_tone, MMF-1 sine, FSH-1. 50-50 mix. Eos reverb).
These last clips show what's possible when putting a FS in the feedback path of a delay:
(e560_fsdelay, EHX SMMH, E560 plus feedback).
Carrier bleed is the bane of the analogue FS. The E560 does not suffer from this. The FSH-1 quotes good carrier suppression, but I initially couldn't get the above patch to work. The more feedback I introduced, the louder the howl of the carrier. I asked Wowa Cwejman who suggested calibrating the FSH-1 to my system/ power supply. Two trim-pot tweaks later and the carrier was as good as gone:
(fsh-1_fsdelay, EHX SMMH, FSH-1).
The build quality of both modules is excellent. The Cwejman has attenuators for its inputs and a VC-able up/ down mix output. The SynthTech has a built-in feedback path and dry/ wet control. To my ears, the FSH-1 has the superior sound, but it is almost twice as expensive. The E560 offers thru-zero shifting but, in practical terms, is limited to low frequency shifts.
Both modules have a ring-mod mode, offering out-of-phase outputs for extreme panning effects. The E560's phaser mode might not be as pronounced as a dedicated unit like the SPH-2, but it is a nice bonus. The FHS-1 can also be pressed into phaser-like duties by mixing dry and wet signals and introducing some single sideband feedback. The E560 alone offers morph-able carrier waveforms, a unique feature in a hardware FS.
Thanks to Paul Schreiber and Wowa Cwejman for taking the time to answer my questions and to Schneidersbuero for the loan of the modules.