An update

Timmer is the working title for a solo project involving double bass and electronics, that has been going on (and off) for the past several years. This autumn I’m fortunate enough to be able to work on it full time for a couple of months. I will try to log the progress here, and very soon also put up some sounds. But first, a long introduction, crammed with all those technical details you love to hear about.

I’m currently preparing the electronics setup, based on an old idea documented here. I’m using transducer speakers mounted on the bass to create a feedback loop, together with the regular contact mic and some filtering in SuperCollider. The filtering and levels should be balanced so the feedback is only happening when a string is open. This makes it possible to manipulate the physical properties of the instrument, making strings resonate infinitely and other nice things.

The idea works in theory, but the hard part has been to find a simple way to do the filtering, which keeps as much of the signal as possible without breaking anything (ears, speakers or bass). Also, I’ve had problems trying to balance the amplitude of different notes.

The first draft of the instrument used parallel bandpass filters, tuned in semitones. To balance the amplitude of the notes, the gain could be adjusted, and I also experimented (a lot) with setting individual short delays on each filter, to adjust the phase. This took a lot of time, but wasn’t very effective. I never really understood what was happening and why some notes were so much louder than the others.

I started to experiment a bit with FFT filtering, trying out UGens like PV_LocalMax and PV_MaxMagN, to only let the most important partials through. I found a few nice effects, but the main problem was still there, with uneven response for different notes.

So, I put a compressor in the end of the filtering chain, which really made a difference. By accident I also bypassed the FFT filtering, which left me with just a lowpass filter, and a couple of peak filters which was supposed to even out the frequency response of the mic and bass. This was the best version yet, and also the simplest. I later expanded it to use 24 peak filters, tuned in semitones from C1-B2. Or was it 25? Something like that.

So, now we have a double bass, a volume pedal, and possible infinite sustain. What can you do with this, besides making drones? Probably a good topic for the next post.