MuRFA24 is an actual look at the very rare and special device, custom-made by “Formula Sound” for sound producer and musician Patrick Gleeson as one exclusive unit. Later, “Formula Sound” (TM) changed the faceplate and ran it in series.
In theory, this device is similar to the Woog String Filter (look to our STRNGFLT rack extension), but with more tweakable possibilities and greatly expanded. This device was designed by R.A. WOOG and produced under the brand “FORMULA SOUND” (TM) in the 70s.
The original Multiple Resonance Filter Array 24 device is a fixed-frequency 24 band filter array. It allows you to simulate the natural resonances of an acoustic chamber (like a violin or other stringed instruments).

MuRFA24 audio processor is a 24 fixed-frequency band filter array. The device radically changes the sound, but less radically than a standard low-pass filter. Incoming signals are fed through 24 steep band-pass filters at various fixed frequencies.
Each of the fixed-frequency bands can be assigned to one or both of the audio outputs (Left. Right, or Left & Right) by bus selector switches. When all the faders of resonance levels are down, the device is fully silent. If various frequency faders are raised, that frequency becomes audible.
The Resonance shift knob, in pair with the Drive knob, allows you to change the overall harmonic tone of the selected frequencies.
MuRFA24 has all 3 the original device modulation modes (Direct, X-Fade, X-Pan), but has one extra mode, X-WIDTH (bandwidth modulation between the fixed-frequency bands). Modulation is one of the beatiful and creative part of the effect, that help to modulate in various ways all 24-bands.
Creating musical expressiveness, the original device was created specifically for the musician Patrick Gleason, and later went into series as very special effect with various modulations of resonated filter array

MuRFA24 is a flexible and modern audio processor, a rare and exclusive audio effect, designed in the earliest era of audio processing in the synthesizer industry.
Try out today the legend from the era of early audio processing from the Moogish synthesis world with flexible and modern features.