SP404 subsonic effect in Drambo

edited April 2022 in Drambo

Not sure how many of you rock 404s but there’s an effect effect on it called subsonic. Roland infamously left this effect out of the mk2 but it got me thinking I’m certain it could be made and improved in Drambo.

For those that are unfamiliar subsonic adds a bass note when your track volume goes over an adjustable threshold. works with 3 knobs, first is to tune the note, second adjusts the threshold which triggers it and third is the wet/dry blend. I’ve got similar results so far using a vca being opened by an envelope follower fed by flexi. haven’t bothered folding and mapping macro knobs yet till I get the idea right. obviously this is more flexible than subsonic in that I could change wave/filter/saturate the note

this all works but it doesn’t really nail the threshold thing as the samples amplitude is pumping the vca which (while similar) isn’t triggering by an adjustable threshold level. any ideas?

Subsonic in effect:



  • Use an envelope follower to track the volume of the audio, a slider or knob to set the threshold, and an A B or B> A function to check for the input being over the threshold. Then you could use that functions on or off signal as the gate for a VCA.

  • I can’t locate A B or B>A. It should be under math right? Can’t see them on my device

  • Those are options in the "Function" module in math

  • excellent will give it a go once I finish work. Thanks guys. Starting to step back on my previous thoughts about phone drambo, it’s quite nice to be able to try a random idea anywhere any time

  • edited April 2022

    There are more ways to add LF rumble:

    The pitch shifter pitched down by 12 semitones and the Math Half Wave rectifier (which works like in the old Boss Octaver pedals).

    A pitch detector could even be built with many Peaking EQ modules

    Add Filtering and maybe a slight delay to the direct signal to improve tightness between the signals in case you're using the pitch shifter.

  • Got in late from work today but I’ll have to give these ideas a go tomorrow! need to dig in and figure out these maths modules

    @bcrichards I got that working! needs to use a touch of attack to kill the click but yeah perfect. Thanks man. Photo of the patch for anyone who might be interested.

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