Synth Sound

[Paul Perry (Frostwave)]

DOD 440 envelope filter (modded with variable Q-control - to put it very close to self oscillating),

My commercial Funk.a.Duck is an envelope follower with a variable-Q control. And adjustable attack/decay.
It's certainly possible to get some synthy sounds out of it - at some settings you can trigger the resonance off as you pluck - but it is pretty difficult to control, in my opinion.

The Boss SYB3 does a reasonable job in my opinion, but it is DSP based. If I wanted to make a synthy kind of pedal, I'd take a Dr Quack type envelope follower & combine it with a Blue Box octave divider. And use the control voltage derived by the Dr Quack to control the output of the Blue Box. (the idea is, put a send/return inside the DrQ so that the input signal can control a completely different one).  I think that would get you a long way toward a synthy sound.

[StephenGiles]

In my view, it always comes back to the EH Guitar Synth, of which my tracings of the circuits are on Mar Hammer's site. I am unable to put my finger on general reluctance to build this - I did in the 1980s on veroboard (I brag again ) and it worked very well, albeit on single notes only. The only parts not currently available are TL601 switches, and I'm sure there is a workaround for those.

[Krinor]

In my view, it always comes back to the EH Guitar Synth

By all means, yes.
I just bought one of these. Fabulous thing. Put a Big Muff after it and you can get some really heavy analog bass/lead sounds. Also try it with an Octavia somewhere in the signal chain. That might give you two octaves up.

[Mark Hammer]

Here's a thought, albeit a somewhat cumbersome one:

1) take a Blue Box
2) take a Bass Balls
3) modify the Blue Box to put out 1 octave and 2 octaves below
4) adapt the Bass Balls so that the octave down from the Blue Box goes through the upper filter, and the sub-octave goes through the lower filter (some tuning required)
5) tweak the envelope-follower characteristics of the Bass Balls so that you have some variation in attack and decay
6) mix down the "normal" fuzz from the Blue Box, plus the two derived-and-filtered signals from the Bass Balls, using a 3-in-1-out simple mixer.

Voila, thick synth sounds.

[flo]

I would try this variation on the basic theme:
- Distortion to create lots of higher harmonics and large compression and sustain.
- ADSR like circuit triggered by clean guitar signal (well, there is no actual release possible because the guitar signal has such a short release by itself...).
- 4pole synth filter (like a Moog lowpass ladder filter or a more versatile state variant filter) with cutoff frequency controlled by an LFO circuit and the ADSR.

[StephenGiles]

In my view, it always comes back to the EH Guitar Synth

By all means, yes.
I just bought one of these. Fabulous thing. Put a Big Muff after it and you can get some really heavy analog bass/lead sounds. Also try it with an Octavia somewhere in the signal chain. That might give you two octaves up.

I'm talking about the rackmount guitar synth, not the microsynth.

[Krinor]

In my view, it always comes back to the EH Guitar Synth

By all means, yes.
I just bought one of these. Fabulous thing. Put a Big Muff after it and you can get some really heavy analog bass/lead sounds. Also try it with an Octavia somewhere in the signal chain. That might give you two octaves up.

I'm talking about the rackmount guitar synth, not the microsynth.

Oh...Sorry I wasn't aware of the existence of a rackmount guitar synth by EH. They've made so many strange things up through the years that it really is hard to keep track of them.

[stobiepole]

Go look at the new guitar synth at musicfromouterspace.com - it'll do what you want and lots, lots more. It doesn't do actual pitch to voltage conversion, but on the plus side there's no tracking problems - it works great on bass as well.

Chris

[Mark Hammer]

Oh...Sorry I wasn't aware of the existence of a rackmount guitar synth by EH. They've made so many strange things up through the years that it really is hard to keep track of them.

Check here: http://hammer.ampage.org/files/1981_E-H_pricelist.gif (it's the 8000)
With a normal retail price of $1500 1981 dollars , you can understand why you had never heard of it!

[Krinor]

I see. Hm... But now that I've heard about it I would of course like to hear it.  It says Steve Howe used it. Any idea on which records ?

[StephenGiles]

I see. Hm... But now that I've heard about it I would of course like to hear it.  It says Steve Howe used it. Any idea on which records ?

Who knows??? I did a recording with mine on reel to reel, but I don't know if I can still play it if I can find the tape. It's not difficult to build, I promise you.

[Krinor]

Stephen, could you post a link to that tracing of yours please ? 

[ppatchmods]

IMO I really like the synth mods on the ds-1 and who is better at that than www.jhspedals.com   His "Synth Drive" is awesome!  He has sound clips that explain his maddness!

[StephenGiles]

Stephen, could you post a link to that tracing of yours please ? 

http://hammer.ampage.org/files/EH-Guitar-Synth.ZIP

[Radamus]

IMO I really like the synth mods on the ds-1 and who is better at that than www.jhspedals.com   His "Synth Drive" is awesome!  He has sound clips that explain his maddness!

Those pedals look pretty interesting. I like the idea of the synth drive, but I'd like to know how it works, or have some sort of schematic, which I'm assuming is not readily available. 

I'm not sure if I mentioned this already, but one sound I'm looking for is the Akai Deep impact. I know that's digital (and ridiculously expensive) but I like the sound the guy from muse gets. I'm not sure I've ever heard the sound minus the big muff though. He always seems to distort it. So I guess after saying that, it turns out I'm not that picky. I plan on building the ugly face soon.

What's the easiest way to really remove all the information from the sound other than the pitch? I know tone controls do this to some extent, but they make the sound either really treble-y or really bass-y depending on the direction.

[flo]

What's the easiest way to really remove all the information from the sound other than the pitch?

Trying to remove ALL information is easy: Set the volume to zero!  But that is not what you want. You want to keep the "pitch" which is the fundamental frequency.
The "information" in a bass/guitar note is in the fundamental frequency plus the various higher harmonic frequencies, together with a non-harmonic noise-like component, and how they relate to each other in amplitude and phase over time.

So removing information is usually reducing harmonics. In electronics this is done with filters so leads automatically to a treble-y / bass-y / dull (single sin tone) sound. For controlling a synth or pitch detection, we try to reduce the higher harmonics with a lowpass filter, trying to keep only the fundamental (lowest) frequency of the tone. This is automatically a more bass-y and dull (=less information) sound.
Another way is to amplify the signal and let it clip. This also reduces information by changing the relationship between the fundamental frequency and the higher harmonics. A "wave-shaper", a distortion pedal or a comparator will do that. Using both techniques in series usually works: First filter then clip.

A pitch detection circuit will be better able to detect the pitch successfull with such a signal because it will get less "confused" by the other harmonics if these are reduced. For instance, a "zero-crossing" pitch detection wants to count only the zero-crossings of the fundamental frequency, not from other higher harmonics because they will make the signal cross though zero much more and can lead to a higher detected pitch. There are other types of pitch detections like the neural network type in the Axon that probably use the higher harmonics for a fast pitch detection.