Electro-Acoustic Research - Model 41


Model 41 is the result of the collaboration between Peter Grenader and Nyle Steiner. The module is a revision of the classic Steiner Parker filter known from the SynthaSystem, including lots of new features. It was supposed to be part of the Plan B portfolio. Unfortunately, the Steiner 4P wasn’t released. – Until now! We are very curious to hear what this filter can do.



The Model 41 takes advantage of the unique Steiner core convention of assimilating it’s three output modes by injecting the incoming signal into three different nodes of the circuit. The three inputs, Lowpass, Bandpass and Highpass, each provide an input attenuator.

By combining the Lowpass and Highpass attenuators to an equal audio level while keeping the Bandpass level fully closed, you can effectively manifest a forth output mode: Band-Reject or Notch Filter.

The filter features both bipolar and unipolar frequency modulation inputs, each with attenuator.

When the M41 is configured as a sound source, an input signal is not required - the user will simply patch the output to it’s destination and turn up the Resonance until the desired output waveshape is achieved.

If the resonance is set higher than 3 o’clock, oscillation occurs and it generates a sine wave. If the Resonance knob is set to max, it results in a clipped sine.    

Furthermore, the Resonance can be voltage controlled thanks to the Res VC input and its dedicated attenuator.

Additionally the module provides push buttons for advanced operation. There are three unique functions on the M41 that have never been implemented into any filter, which dramatically increase it’s timbral footprint: IFM Sync, HyperQ and a variatible Sprectral Energy Distribution manual control.

If the IFM Sync button is pushed, an internal patch has been engaged to the frequency control circuit which manifests quantized harmonic resolution. It introduces a secondary resonant frequency harmonically constituent to the first. This dramatically affects the output timbre.

The Hyper Q distortion mode is similar to IFM Sync, but applied to the Resonance control circuit. If the ingoing waveform is negative, the polarity buttons should be pushed. If you are not sure of the phase of the waveform- try both settings of the Polarity push button and it will become immediately obvious which is required.

The M41 has been equipped with a variable Spectral Energy Distribution (SED) control which lessens the intensity of the filtering without the phase problems associated with a standard dry/wet crossfader. To engage, press the Enable push button and set your desired SED level with its pot.

Audio input and output
Two Frequency VC inputs
Resonance VC input

3U Eurorack module, 14 HP wide, skiff-friendly
Power consumption: 60 mA at +12 V

0.2 kg
Article Number
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€ 19% VAT excl. €200.00 € 19% VAT incl. €238.00
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