Dual Multimode Filter

The RT451 features the popular multimode filter of the Radikal Technologies Spectralis synths in a special, dual package for the Eurorack modular synthesizer world. You can create widened and spatial stereo sounds, cascaded or parallel filter operation with total new filter responses, or two fully independent resonating filters; opening a new world of analog filter sounds that will take your modular synthesizer timbres to a completely new level.

The RT451 comes with an extra large „Coupler“ knob that controls both filter cutoffs instantly. You can set the frequency spacing between both filters with the individual cutoff controls, and increase/decrease both filter frequencies simultaneously with this big knob.

The RT451 also has CV inverters and signal multiples; more behind the elegant front panel than meets the eye. The signal and CV inputs of filter 1 are internally connected to filter 2 as long as there is no cable inserted into the filter 2 jacks. If you connect one LFO to the CV-1 input of filter 1, the CV depth knob of the second filter controls the depth of the control voltage modulation for the second filter independently from the first filter.

The RT451 also excels in modulation control. In center position, the modulation depth is zero, but turning the CV-depth control knob can cause the control voltage to create many unique filter effects. When the control voltage is increased by turning it to the right, the frequency of the filter will also get increased, but by turning the control knob left from the center position, the control voltage will decrease the cutoff frequency of the filter as well. CV depth of both filters can be set to opposite values for great stereo effects.

Take your sound to a wider spectrum with the RT451!

A short demonstration of the final release version:

RT451 vs. Spectralis drumgroove

Radikal prepared two audio demonstrations with the NAMM prototype at Jörgs soundcloud channel:

Kickdrum programming with the RT-451:


  • 80 mA +12V
  • 80 mA -12V
  • 0 mA 5V
  • 25 mm deep
  • Ø 4.40 (5 Votes) Average Rating

This Module is currently available.

32 HP Filter
submitted Feb 11th 2015, 23:54 by Elektro_Lurch | last Change Jul 23rd 2017, 03:41 by Elektro_Lurch
Specs are approved by the manufacturer

Date Region Description Price Seller
EUThe overall condition of this *Radikal Technologies RT-451* is *very good* ...$390.00FedorSynthman View
USAThe overall condition of this *Radikal Technologies RT-451* is *excellent* ...$295.00BTG View

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