Thank you both 
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Has anyone tried feedback (not feedforward) compression with the rnc’s sidechain input?
I’ve just been reading about it, using the output signal to drive the compression.
I saw it on that Stimming imc to great effect. I don’t have my gear set up atm to try it.
Hello everyone.
I assembled a small passive HPF CR first order filter
The FMR developers specify that the SChain resistance is 20 kOm. Simple calculations and scheme is done. Experience specify that low cutoff values do not work well (because first order is 6 dB to octave).
Summary cap values and switch positions:
- Virtual Bypass (SCchain is disabled)
- Full range
- 360 Hz Cutoff
- 800 Hz Cutoff
- 1170 Hz Cutoff
P.s. Knob will be replaced
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Oooh, that’s a big knob you got there 
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Have to disagree here. I use an 82nF capacitor on sub-heavy techno material, and the difference in gain reduction when I take it out is huge.
Perhaps it depends on the frequency response of the kick.
I’ve got both RNC and RNLA sitting here, and hoping someone with experience with either can give me input on a gain staging issue.
When I disengage bypass (on either unit), I get about 10-15db decrease in volume, with the gain knob set to 0db, and compression settings such that no gain reduction is taking place.
This makes A/B’ing a compressed vs bypassed sound infeasible, since the gain knob only gives me ~15db increase at the max setting, so max non-bypassed gain (with no gain reduction) is about level with the bypassed signal. Effectively this leaves me with no makeup gain option, since all compression at this point is reducing volume from the dry signal.
Is this usual behavior for these units?
No. I’d bet either you are compressing, or you have a phase issue treating a stereo signal as balanced or vice versa. Can you try to simplify your setup to the bare minimum number of cables and components that produces the effect and describe it to us?
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Thanks for the response.
Connections were two 1/4” TS cables for L/R input, dual 1/4” TS to stereo TRS output.
I was monitoring on headphones straight from the comps, and suspect there was a sensitivity issue with this configuration. Not a real concern, I was only hooked up this way to check that they worked after delivery.
I’ve moved them down into my main setup, similar connections but through a mixer, and bypassed gain now matches enabled gain (no compression) at 0db makeup setting, so everything working as expected.
I’ve in the meantime noticed the inputs also work as In/Outs, so can run as channel inserts with a single (or pair of) TRS cable(s). Lovely boxes.
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If anyone is interested in building an interchangeable sidechain filter solution like Xopek, but find it a little too involved, there is another more rudimentary way of doing it. You will need:
- A TRS jack connector
- Two leads
- A way to solder the leads onto the connector
- Two Wago electrical connectors
- Any number of different capatictors
Simply solder one lead to the tip of the jack connector, and one to the ring. Insert each lead into it’s own Wago connector. Then insert a capacitor into each Wago connector. Capacitors can now be swapped with relative ease.
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Thanks for sharing! This looks like a fun DIY project! Currently have a Behringer eq pedal for this, but this looks fun to try.
Do you have two or three capacitors you’d advise?
82nF you use right?
And what else would be good to try?
You can calculate yourself, using this High Pass Filter Calculator.
Simply enter the resistance in the sidechain circuit (it’s 20 kOhm according to Xopek) and the cutoff frequency you would like, and it will calculate what capacitance you will need. I found that 82nF, which results in 97Hz cutoff works well on my material.
For reference, my IGS Buss Compressor has a 60, 90, and 120Hz sidechain filter built in.
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Fun!!
Going to order some capacitors for the first time in my life 
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