Behringer FM600: A Happy Accident

Earlier this ear I was shopping on amazon for cheap distortion pedal and  a pitch shifter. However, I must have been drunk, or something, because I ended up with this purple pedal on my doorstop. But I’m happy as I could be with this purchase, as this pedal is capable of bringing a new array of sound to my pallette, for a very modes price (about 40 €).

So, what is the pedal I’m talking about? It is the Behringer Filter Machine FM600. It comes in the same plastic box format as the FM600 and the RV600, but with a purple lively, that somehow matches the one on my Streichfett.  This is a mono pedal: it only has one input and one output, both using a 1/4″ TS (Mono) jack socket. Next to the Input socket you’ll find the usual 9V center-pin negative power input. There is also a battery compartment underneath the pedal, but I never use this things on batteries, and replacing the battery on this pedal format looks to be a little bit tricky.

The front panel is a three knob affair, with two additional switches, and the inevitable stomp pedal (although I don’t recommend stepping it too hard). The knobs are labelled SENS,  RANGE and PEAK, while the switches allow you to choose the type of filter and the polarity of the modulation. And this is where my synth-oriented head starts to search for the cutoff knob: there isn’t one! For each filter type (more on those later) the cutoff frequency depends on the combination of the SENS and RANGE knobs. In fact, SENS appears to be the main Cutoff controller, while Range sets the value for a fixed-rate transient envelope (something like an attack-sustain envelope). Of course, the value of range not only adds the transient felling (less than a second attack), but also the level at which the Filter cutoff is set when the transient ends.

The FM600 has “Real Circuit Modelling” technology, as advertised on the front panel. Supposedly this allows for a more analogue-like sound. Judging from the test I made with the Volca Keys,  the pedal sound quite nice, although the filter is much less crunchy than any of the analogue filters I own (currently: MS-20 filters from the Monotron/Monotribe, the RV700 filter from the Volca Bass and Keys, and also the Steiner-Parker from the MicroBrute)… There are three modes to this Filter Machine: Band Pass (BP), Twin, and Low Pass (LP). The Low Pass looks like it’s a 12dB/Octave resonant filter… nothing to write home about, but still usable to tame high frequencies(it will filter most things above 10 kHz). Because this pedal is mono, I tend to split the incoming signal, and record one track with the dry (unfiltered) audio and another post-filter. In the mixing process I end up with an instant EQ just by balancing the two tracks.

The Band Pass appears to be also 12 dB/Octave, and goes from very broad to almost a needle in the spectrum, depending on the peak settings. The modulation is more noticeable in this more than in LP, and creates some interesting transients.

Finally I came across the Twin Filter setting. This is what really made me love this gadget. It is basically a dual band-pass filter (2 band-pass filters in parallel). They appear to be centred at about 500Hz (perhaps 440 Hz). Turning the SENS knob changes the relative position of both bands, until they cross (performing effectively as a BP filter) and then moving apart in opposite directions of the frequency spectrum. Using the modulation (RANGE) and adjusting the PEAK, this gives very vocally sounds, which I simply adore… specially when playing bass lines with the  Volca Bass.

Last, but not least, there is a Polarity switch bellow the Peak knob. Any sensible synthhead will think this is affects only the sign of the modulation envelope, but no… not in guitar world! This little switch not only inverts the signal of the modulation envelope: it also inverts the signal coming from the SENS knob. That’s right: if you want negative modulation on the Filter, turning the SENS knob to clockwise will decrease the cutoff frequency (or the centre frequency of the BP, or the band distance of the twin filter)! This is not a deal breaker for me, specially because those little knobs don’t have the best feel for live tweaking, but is still something to have in mind when working with this machine.

If you are interested in buying one , this pedal is available from Amazon, for about 40 USD, or Amazon (UK), for less than £30, but the prices vary a lot over time, depending on stock management and promos.