What wave?

[Kipper4]

So I'm wanting to put a fuzz in a sweller circuit to mimic bowed string effects.
What's the optimum fuzz for string sounds.
Are there any existing circuits I should look at?
Thanks
Rich

[sergiomr706]

I m a totally dummy electronically, but I thought, what would happen trying the gretsch contrafuzz or contrafrizz and some kind of swell device, like the paia gator, string damper or something a little tiny like this, http://www.madbeanpedals.com/forum/index.php?topic=26317.0 
The contrafuzz maybe could benefit from having the clean first part of the sound faded and then going dirtier as the volume increases too. Not sure if that is what you have in mind for "string ed fuzz" Good luck !

[stallik]

An earlier version of DeadAstro's spitfire (Mk3? the one with 3 switches) set to fuzz which adds the extra c15 cap into a Maplin noise gate set for the swell effect gets me the sounds I think you're referring to. Violin above 12th fret, cello in the mid and whale music on the bottom strings.

You might like to check the circuits and see whats going on - I'd be interested if you put it all in one box...

[Mark Hammer]

Does anyone know anything about the progression/introduction of harmonic content as a string is bowed?  I ask because I know that more realistic emulation of backwards tape, in the analog domain, involves varying the introduction of harmonic content,  in addition to the amplitude envelope.  So I'm wondering if mimicking a bowed string also involves starting out or ending up with something other than an obvious fuzz.

[Govmnt_Lacky]

Isn't the EHX Attack Decay supposed to do this very thing? Emulates bowed strings??

[ElectricDruid]

I don't know about *real* strings, but I do know how they're usually synthesised on synths. You'd start with a ramp waveform, and then you'd add the slow attack that's already been mentioned, and a little bit of filter movement too - so that's the "changing harmonic content" Mark mentioned.

I'd avoid any comparator-based fuzzes as probably much too "square wavey". You want something rich, but not all odd harmonics. Add a slow swell, and if you can sweep some basic filter with the envelope too, so much the better.

Tom

[Elektrojänis]

I don't know about *real* strings, but I do know how they're usually synthesised on synths. You'd start with a ramp waveform, and then you'd add the slow attack that's already been mentioned, and a little bit of filter movement too - so that's the "changing harmonic content" Mark mentioned.

I'd avoid any comparator-based fuzzes as probably much too "square wavey". You want something rich, but not all odd harmonics. Add a slow swell, and if you can sweep some basic filter with the envelope too, so much the better.

I thought that many synth patches for strings use pulse wave... By the sound of it I would guess that narrower pulse would work for lower notes or lower range instruments and higher ones could be a bit more squarey.

So... The comparator stuff and other hard clipping fuzzes might work if you make it asymmetric.

Slight modulation in the pulse width might be beneficial too and a bit of (low pass) filter sweep on the attack with the volume swell could help. Actually... I'd try with just the filter swell for a start as it will cause some volume swell too if you start the sweep lower than the note being played.

[deadastronaut]

Space patrol fuzz, setting 4....

nice n synthy and swelly already...should go nice with a real swell...

[ashcat_lt]

While the bow is on the string and moving, the harmonic content doesn't change much because the string is pretty much always being "attacked".  After bowing stops, it drops off to just the fundamental pretty quickly just like any other string.

If we're doing gate-type autoswelling, the gate should probably be sidechained - reacting to the clean input dynamics, but affecting the extremely fuzzed output.  A similarly sidechained VCF after might help, too.

[Kipper4]

Wow some super hardcore info.
Just what I wanted.
Great thread.

I have much homework to do.
I guess the VCF would want It's envelope set differently to the gate.
MFB with vactrol maybe.

I need to reread.
Thanks guys.

Rich

[anotherjim]

Actually, a narrow & spikey sawtooth. That is difficult to produce by filtering. Square it, high pass it. Only works within a 2 octave range due to limitation of filtering for waveshaping. Otherwise its back to the difficult proposition of having a VCO track the guitar pitch.
Pulse also works and is easier. PWM can give impression of bowing and string chorus. Either way, if you make square or pulse from the guitar, attack will be glitchy. Slow envelope attack (which you want anyway for bowing effect) can hide the glitch, but note-off detection has to work well to make sure every new note gets the slow attack to hide glitching. Volume pedal swelling can do that much better than auto. So FF type distortion into volume pedal can be just as good as any "special" analogue circuitry.

[ElectricDruid]

I don't know about *real* strings, but I do know how they're usually synthesised on synths. You'd start with a ramp waveform, and then you'd add the slow attack that's already been mentioned, and a little bit of filter movement too - so that's the "changing harmonic content" Mark mentioned.

I'd avoid any comparator-based fuzzes as probably much too "square wavey". You want something rich, but not all odd harmonics. Add a slow swell, and if you can sweep some basic filter with the envelope too, so much the better.

I thought that many synth patches for strings use pulse wave... By the sound of it I would guess that narrower pulse would work for lower notes or lower range instruments and higher ones could be a bit more squarey.

So... The comparator stuff and other hard clipping fuzzes might work if you make it asymmetric.

Slight modulation in the pulse width might be beneficial too and a bit of (low pass) filter sweep on the attack with the volume swell could help. Actually... I'd try with just the filter swell for a start as it will cause some volume swell too if you start the sweep lower than the note being played.

Yes, agreed. Moving away from 50/50 duty cycle is another way to get those even harmonics in there, so narrow pulse would work too, and adding a bit of pulse width modulation is a good idea. I think I had a string patch on the Korg Polysix that was set up like this.

Tom

[FiveseveN]

I always thought sawtooth waves were used for string synthesis "since the slip-stick behavior of the bow drives the strings with a sawtooth-like motion."
http://www.zainea.com/Oscilationsofbowedstring.htm

"Real recorded cello" for reference:

[DIY Bass]

I know that my Boss GT-6B has a passable simulation of a bowed double bass that uses a Slow Gear effect into a lot of fuzz.  I have no idea which of the simulated fuzz pedals they use for it, but I can look it up if you like