Synth Sound

[Radamus]

Hello. I'm looking to make a synth sound pedal (mostly for bass). I've seen the bass micro synth schematic. That's pretty complicated and it uses a lot of features I don't understand. Is there anything that more simply uses frequency to control a timing circuit that emits a frequency? I guess I'm just asking what my analog synth options are.

Thanks in advance.

[StephenGiles]

Yes I'm sure there is, but it won't be simple! In my experience, simple usually means a trade off between mediocre and bad.

[Meanderthal]

 None of the circuits that fit the bill of what you're looking for seem to work very well.

Part of this is the fact that bass is an octave down, the strings vibrate half as fast as guitar, so it takes twice as long to figure out what you're playing.

Yes, I've been looking for a simple bass synth too. Wishful thinking though.

A pseudosynth like the microsynth is your best bet for actually using, since there's no real tracking involved.

Try different distortion, envelope follower, phaser, chorus, octave up, delay combinations. Some synthy sounding stuff possible there.

[Radamus]

I'm curious to see what the circuit for one of those synth sound things would look like. I'd like to at least try it. Any links?

[Krinor]

Have you checked out Tim Escobedo's circuits ?

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html

[Processaurus]

Have you checked out Tim Escobedo's circuits ?

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html

PWM, ugly face, and simple squarewave shaper made simple are great, fun, glitchy, and simple circuits.  MXR blue box is in a similar boat.  I combined several of tim's circuits and a blue box into a psuedo synthesizer effect box, and liked the results a lot.  Not mediocre at all.  Though it got almost micro-synth complicated by the end...

For a more complex but documented guitar synth project, there is also the "music from outer space"" guitar synth kit.

http://musicfromouterspace.com/analogsynth/GUITARSYNTHAUG2007/GUITARSYNTHAUG2007.html

[Mark Hammer]

One of the things I've noticed when tinkering with autowahs is that they sound more "synth-like" when the decay time is shorter and the resonance is a little higher.  That is obviously separate from whatever perversions you do to the signal on the way to the filter.

Shortening the decay time is frequently a matter of reducing the value of a resistor in parallel with the time-constant ("averaging") cap to ground.

[soggybag]

Ugly Face sounds pretty synth like at times. Adding an attack decay type envelope to the Ugly Face might be interesting...

[Radamus]

This may be a dumb question, but is there any part that can be controlled by frequency? and can it be controlled by frequency to emit a frequency?

[FisTheGoon]

Ugly Face sounds pretty synth like at times. Adding an attack decay type envelope to the Ugly Face might be interesting...

+1 on Ugly Face.Recommended. love it man.need a bit tweaking to reduced the noise.After all it can produced  synth and also space gun that really makes me to build this. cheers

[Mark Hammer]

This may be a dumb question, but is there any part that can be controlled by frequency? and can it be controlled by frequency to emit a frequency?

Yes.  http://hammer.ampage.org/files/GuitarP2V.PDF

As the article would suggest, however, it isn't a trivial task to do so.  Still, you CAN derive a voltage proportional to the pitch of a note that can be used to control other things.  Note that the old Boss DF-2 Feedbacker derived the pitch of the input note to control an oscillator.

[Mick Bailey]

+1 on Ugly Face.Recommended. love it man.need a bit tweaking to reduced the noise.After all it can produced  synth and also space gun that really makes me to build this. cheers

Can you tell me what tweaking you did?

[Radamus]

I definitely saving the idea of making a frequency to voltage to frequency device 'til much later, but can something like that make chords? If it creates a voltage, I'm assuming you can't have two, so chords are kind of out of the question? How could I remedy this?

Thanks for the other recommendations. I'll be building the ugly face and PWM in my next batch.

Thanks

[Paul Perry (Frostwave)]

If you have a frequency to voltage converter, then you will get a voltage that is proportional to the input frequency and so, you can only drive it with a one-note input.

But, you can take the output, and that can be used to control a number of separate oscillators, so you can have a chord generated.
Because, it is easy to make another control voltage that is a fixed proportion of the output from the freq to V converter.

[snufkin]

I have been thinking about guitar synths since I first started pedal DIY a few years ago. I asked these same questions

I am currently building a mono guitar synth based off the p2v schematic on mark hammers archive (thanks for the resource mark!  ) ill try and post a build report when I finally get time to finish it (ie months away) 

I have been thinking a for a simple poly synth sound you shouldn't use a crazy oscillating ugly face style fuzz

instead you could pair a smooth  fuzz that handles chords well with a lfo controlled filter and a volume pedal (for the swells)

any suggestions for the fuzz as I'm no expert

of course after that anything else could be added on top like chorus

hope that helps

[Mick Bailey]

In the 80's I had a Korg guitar synth. Whilst it required a distinct playing technique for some of the tracked sounds, the VCF was excellent on its own and it had some really interesting sounds for chord work. I always thought some of the circuitry could be lifted and built into a pedal, but that was pre-internet days and I never found a schematic.

http://www.sequencer.de/pix/korg/korg_guitarsynth.jpg

[Mick Bailey]

Just found this;

http://www.youtube.com/watch?v=hNYUdS3KbLY

[flo]

Another route for guitar synth stuff would be not to build a lot of complicated analog circuitry for pitch detection and tracking etc but to use PC software for this together with plugins or something like Reaktor. This is a lot more flexible, adjustable and a lot of fun!
An the other hand, I do agree on previous posts that using a distortion / fuzz / squarewave-shaper together with a VCA & VCF & LFO circuit can give nice synthy sounds without getting into the whole pitchtracking issue. Use the guitar as an oscillator in a basic subtractive synth setup.

[Radamus]

This is a lot of great input. Thanks a lot.

Use the guitar as an oscillator in a basic subtractive synth setup.

Assume I'm an idiot, because I probably am. How does that work? I am certainly open to alternate ways of achieving the synth sound, but I haven't really heard a fuzz yet that sounded right. At the same time, My goal is to make the synth sound and then run it through a fuzz. This probably isn't much of a comparison, but I ran my bazz fuss through my big muff pi and it sounded... muddy. If there's a way to just strip information from the notes I'm playing or to have a more specific frequency to frequency converter (minus the voltage part in between) please let me know. I'm willing to try some things.

I have been thinking a for a simple poly synth sound you shouldn't use a crazy oscillating ugly face style fuzz

instead you could pair a smooth  fuzz that handles chords well with a lfo controlled filter and a volume pedal (for the swells)

How do the LFO and volume pedal help to create the synth sound?

[Krinor]

Use the guitar as an oscillator in a basic subtractive synth setup.

Assume I'm an idiot, because I probably am. How does that work? I am certainly open to alternate ways of achieving the synth sound, but I haven't really heard a fuzz yet that sounded right. At the same time, My goal is to make the synth sound and then run it through a fuzz. This probably isn't much of a comparison, but I ran my bazz fuss through my big muff pi and it sounded... muddy. If there's a way to just strip information from the notes I'm playing or to have a more specific frequency to frequency converter (minus the voltage part in between) please let me know. I'm willing to try some things.

Basically a synth consists of tone generators (oscillators) and various filters and tone shaping effects. In the case of a simple guitar synth (like for example the EH Micro Synth) the guitar signal replaces the tone generator.

In my own experience making a guitar sound more like a synth partly consists of making it sound as little like a guitar as possible. This can be achieved by adding octave effects, square wave, envelope filters, ring modulators etc. Personally I found some very interesting sounds using the following chain of effects: Guitar (neckpickup with tone rolled off) into Big Muff, Tycobrahe Octavia (the GGG version with pregain control to roll off most of the fuzz), DOD 440 envelope filter (modded with variable Q-control - to put it very close to self oscillating), Small Clone Chorus, Delay (slap back for rythmic repeats). This sounds pretty strange - and not at all like a guitar.