Frequency to CV Conversion

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Lux_Seeker
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Joined: Thu Mar 26, 2009 8:44 pm

Frequency to CV Conversion

Post by Lux_Seeker » Wed Apr 29, 2009 8:21 am

In a couple of the posts here, the issue of frequency to CV conversion has come up. I would love to see an extended version of the Freqbox or perhaps a new fooger with frequency to cv or perhaps, combined with an envelope follow.

Pitch followers have had a varied history in electronic music and for whatever reason never became prominent. I put together a limited history here:

Gentle Electric

http://www.gentleelectric.com/

EMS Synthi 100

http://www.ems-synthi.demon.co.uk/emsprods.html#accs

In his early years, Robert Moog also used one and a four oscillator sythesizer:

http://www.furious.com/perfect/moog.html

Morton Subotnick's Ghost Box (pitch and envelope follower):

http://www.newalbion.com/artists/subotnickm/

Just in case you think analogue pitch to CV convertors are not around there is the RS-35 module from analogue systems complete with audio demo:

http://www.analoguesystems.co.uk/index2.htm

If you listen to the demo you will hear a synthesizer being controlled by a guitar which sound far superior to me than the current useless brands of pitch to MIDI convertors.

I would love to know how this is done in an analogue realm. As some may have figured out, I hate the way its done in the digital realm but this is an interesting alternative and if you have a modular or are thinking about getting one, not that expensive an option.

EricK
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Post by EricK » Wed Apr 29, 2009 10:12 am

Interesting article. Ill bet we will see the unit he was talking about when they get his archives in order.
Support the Bob Moog Foundation:
https://moogfoundation.org/do-something-2/donate/

I think I hear the mothership coming.

Vitja
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Location: Slovenia

Post by Vitja » Wed Apr 29, 2009 3:37 pm

I have concept written by Bob Williams of Analogue Systems.
He posted this for me when I was asking about RS-35 Pitch to CV converter.
This is a patch which is basis for good tracking and you have some examples
on youtube.
Here it goes:




RS35 MASTER PATCH

MODULE REQUIREMENTS : 1 X RS35 EXTERNAL PROCESSOR
1 X RS95vco
2 X RS100/110 FILTERS (FILTER A/FILTER B)
1 X RS170 MULTIPLE
1 X RS180 VCA
1 X RS270 ADAPTOR MODULE


PATCH :BRING EXTERNAL SIGNAL (FROM AUXILIARY SEND ON DESK) INTO THE SYSTEM VIA RS270 ADAPTOR MODULE.FROM CONVERTED PATCHCORD TO 3.5MM PATCH TO SIGNAL IN OF ONE OF THE RS100/RS110 (WE WILL CALL THIS FILTER FROM NOW ON) AND PATCH ITS LOW PASS OUTPUT (ZERO RESONANCE) TO FREQ IN OF RS35.
MAKE SURE BOTH TOGGLE SWITCHES ON THE RS35 ARE IN THE DOWN POSITION)
PATCH OUT OF V-HELD OUT TO ONE SIDE OF THE RS170 MULTIPLE .
PATCH FROM MULTIPLE TO 1V/OCT OF FILTER A,FILTER B AND RS95
PATCH OUT OF RS95 INTO SIGNAL 1 OF FILTER B
PATCH OUT OF LOWPASS OUTPUT OF FILTER B TO SIGNAL 1 OF RS180
PATCH OUT OF RS180 TO DESK.
PATCH OUT OF LEVEL-V OUT OF RS35 TO OTHER SIDE OF RS170 MULTIPLE THEN PATCH ON TOWARDS LIN IN OF RS180 (TURN LIN POT TO MAX).MAKE SURE INITIAL GAIN POT IS AT OR NEAR ZERO
PATCH FROM THE MULTIPLE THAT FEEDS THE RS180 TO THE VC IN VARY OF FILTER B

BASICALLY A SUBTRACTIVE PATCH OF A VCO IS BEING FED INTO A FILTER WHOSE OUTPUT IS FED TO A VCA THEN ONTO SOUND REINFORCEMENT/DESK.

INSTEAD OF ENVELOPE GENERATORS OPENING AND CLOSING THE FILTER/VCA COMBINATION THE LEVEL-V OUT OF THE RS35 (IN OTHER WORDS ENVELOPE FOLLOWER) DOES THE SAME JOB
IMPORTANT!! THE LEVEL-V OUT IS DEPENDENT ON THE TRIGGER SENSE POT OF THE RS35 AND IT SHOULD BE SET SO WHEN AN INCOMING SIGNAL IS DETECTED IT LIGHTS UP (RED LED) TRY TO KEEP THE TRHRESHOLD TO MINIMUM.

INSTEAD OF A CONVENTIONAL KEYBOARD TRACKING THE PITCH OF THE RS95 VCO THE PITCH IS NOW GENERATED BY THE V-HELD OUTPUT OF THE RS35 WHICH IN TURN IS CONVERTING THE FILTERED INCOMING SIGNAL (BY FILTER A) OF THE EXTERNAL SOURCE.

NOTE:THE REASON THE INCOMING SIGNAL IS FILTERED (UNNECESSARY WITH VOCAL) IS TO REDUCE THE HARMONIC CONTENT OF THE GUITAR.THE RS35 WOULD TRY TO JUMP FROM ONE RESONATING STRING TO ANOTHER BEING CONFUSED BY THE HARMONICS.BY FILTERING DOWN THE INCOMING SIGNAL TO A SINE WAVE THIS CREATES A STABLE ENVIRONMENT FOR THE RS35 TO ACT UPON. A





FURTHER ENHANCEMENT IS THE FACT THAT FILTER A IS NOW A TRACKING FILTER DUE TO THE TRICK OF SPLITTING THE V-HELD OUT AND SENDING IT TO FILTER A’S 1V/OCT INPUT AS WELL AS FILTER B AND RS95.

THE LEVEL V OUT POT SHOULD BE SET ABOUT ¾ WAY
CV IN VARY OF FILTER B MOSTLY IN ANTI CLOCKWISE POSITION (DEPENDING ON CUT OFF REQUENCY SETTING)

THE RS95 SHOULD BE IN WIDE MODE WHICH IS CONVENIENT FOR TUNING THE VCO TO THE SOURCE INSTRUMENT,FOR EXAMPLE THE OSCILLATOR SHOULD BE TUNED TO THE PITCH OF YOUR VOCAL RANGE IF THE VOICE IS BEING USED AS A SOURCE OF CONTROLLING THE SYNTHESIZER AND AGAIN,RE TUNED IF A BASS GUITAR IS BEING USED AS A CONTROLLER.

IT TAKES TIME TO FIND OPTIMUM SETTINGS AS EACH NEW SOURCE WILL REQUIRE A DIFFERENT APPROACH.THE FREQUENCY OF THE TRACKING FILTER A IS THE MOST IMPORTANT AS IT IS THE KEY TO PERFECT TRACKING

BOB WILLIAMS 3/07

Vitja
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Location: Slovenia

Post by Vitja » Wed Apr 29, 2009 3:49 pm

I think we really need something like that in MF format,
but anyway this is my next gadget on the list.
I know that this would be wonderful for guitarist/bassists/violinists or whatever you play,we could finally play a SYNTH! ... not in a MIDI fashion but all analog and that is the point here!

MF-106 Pitch/Env. Follower :twisted:

Lux_Seeker
Posts: 473
Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Wed Apr 29, 2009 9:12 pm

I don't think the analogue solutions modules are digital/MIDI are they? I frankly dont' ever want to use any pitch to MIDI device. Surely the early gentle electric pitch to CV devices were not digital so there is a way to do this in an analogue way.

Vitja - Great post, thanks. I will have to take some serious time to read this but this is realy intersting and useful to think about.

Lux_Seeker
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Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Wed Apr 29, 2009 9:19 pm

I am not really seeing frequency to CV in terms of the traditional MIDI guitar synthesizer but in terms of the way Morton Subotnick used pitch followers but to shape transient sounds. Foogers seem more to lend themsevles to the experimental realm. I know that the majority use is to use them as guitar pedals but in many ways, that seems like using a Lamborgini to drive around a parking lot.

Vitja B
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Location: slovenia

Post by Vitja B » Thu Apr 30, 2009 11:20 am

Do you mean System or Solutions?

When you have decent pitch follower you can do so much things!

I would like to alter my guitar tone in a very specific way.
Not just to play an oscilator but to mix some specific timbers to
my clean tone in a very careful way,this is concept where I want to
ad a interesting color to pure melody or harmony,when there isnt
time for abstract timbers or something like that,because there is already
complex music going on and sometimes less is more!
But there is so much space where you can explore all spectrum of what can you do,when music tells you is the right time.
Im toking about jazz kind of aesthetics,which is hardest environment to listen to each other in band,
follow the chord changes(which are really complex),do all the rhythm shiftings and on the other hand follow the form,yet play expressive melodic concepts and finally have a control over sound you want to express! Doing all this in relax manner .... well,it is possible and when it is possible,it is beautiful to play all that crap.

:D

Lux_Seeker
Posts: 473
Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Thu Apr 30, 2009 11:27 am

Vitja B wrote:Do you mean System or Solutions?

When you have decent pitch follower you can do so much things!

I would like to alter my guitar tone in a very specific way.
Not just to play an oscilator but to mix some specific timbers to
my clean tone in a very careful way,this is concept where I want to
ad a interesting color to pure melody or harmony,when there isnt
time for abstract timbers or something like that,because there is already
complex music going on and sometimes less is more!
But there is so much space where you can explore all spectrum of what can you do,when music tells you is the right time.
Im toking about jazz kind of aesthetics,which is hardest environment to listen to each other in band,
follow the chord changes(which are really complex),do all the rhythm shiftings and on the other hand follow the form,yet play expressive melodic concepts and finally have a control over sound you want to express! Doing all this in relax manner .... well,it is possible and when it is possible,it is beautiful to play all that crap.

:D
Analogue systems, sorry for the misprint. Here is the line for the RS-35:

http://www.analoguesystems.com/

As for jazz, that is something else again.

Vitja B
Posts: 42
Joined: Thu Apr 30, 2009 5:41 am
Location: slovenia

Post by Vitja B » Thu Apr 30, 2009 12:18 pm

Yeah,but when you start to explore different concepts and you expand your imagination as a group together, you are able to play anything.
But this is life time gob.
MF-101,MF-102,MF-104Z,MP-201,PRS Custom24/10 top,Acoustic G100T,many more.

dr_floyd
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Joined: Wed Jan 28, 2004 3:43 pm

Post by dr_floyd » Thu Apr 30, 2009 3:36 pm

Here are some p/v converters from a 2006 Moog Forum post:

1. Roland SPV355 Pitch to Voltage Synthesizer - includes a tunable two osc (plus sub osc), vcf, vca, portamento and lots of foot controller options, plus pitch cv out, env follower out, gate out, and pitch cv in gate in. I think this evolved from a module on the Roland 100 modular synthesizer. The oscillators and filter sound great - thicker than the later Jupiter stuff. Tracking can be iffy, but with care this thing is great and always musical.

2. Gentle Electric Model 101 Pitch and Envelope Follower - very nice and complete processor, also used in the Serge modulars (I'm pretty sure). Various pitch cv outputs, env follower outs (linear/exponential), gate/trigger outputs, preamp out, insanely compressed preamp out. Has to be set up carefully, but works well.

3. EMS Pitch-to-Voltage Converter - made by British Synthi/AKS company, used by Eno, seems very similar to Gentle Electric, but with a few more features. I've never actually seen a real one. http://www.oldtech.com/synth/Ems-PtoV-big.jpg

4. Fairlight Voicetracker - both pitch/env/timbre to cv, and pitch/env/timbre to midi, with a single digital oscillator with modulation basic synthesizer on-board, which doesn't sound so good. Fully featured, lots of setup possibilities, real-time video output of pitch, timbre, env, etc. Only converter I've seen that contains a timbre to cv/timbre to midi output. Has one drawback regarding re-triggering/legato playing in that it doesn't always follow the pitch change with legato playing.

5. Arp Avatar - great sounding synthesizer, I am now rigging an input cable to test the pitch to voltage conversion with woodwinds rather than guitar, so don't know yet. Avatar is literally an Odyssey without a keyboard, but with p to v converters and fuzz.

6. Korg MS-20 - always fun, tracked woodwinds accurately for 3 octaves in my experience, but the linear voltage output instead of 1V/oct limited its appeal, and the sound never grabbed me. Lots of fun though.

There are also several pitch to midi converters that you could then use a midi to cv converter: Roland VP70, Roland GM70, Roland GI10, Roland CP40, Axon AX100, Yamaha G50, Pitchrider series...

Moog Modular 912 Envelope Follower was a common in the modulars.
A Moog 1634 Pitch-to-Voltage module did apparently exist, but I cannot find any information beyond the module number. Maybe this is the module Bob Moog referred to with Eddie Harris' 4 osc. saxophone thingy.

Lux_Seeker
Posts: 473
Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Thu Apr 30, 2009 4:27 pm

Vitja B wrote:Do you mean System or Solutions?

When you have decent pitch follower you can do so much things!

I would like to alter my guitar tone in a very specific way.
Not just to play an oscilator but to mix some specific timbers to
my clean tone in a very careful way,this is concept where I want to
ad a interesting color to pure melody or harmony,when there isnt
time for abstract timbers or something like that,because there is already
complex music going on and sometimes less is more!
But there is so much space where you can explore all spectrum of what can you do,when music tells you is the right time.
Im toking about jazz kind of aesthetics,which is hardest environment to listen to each other in band,
follow the chord changes(which are really complex),do all the rhythm shiftings and on the other hand follow the form,yet play expressive melodic concepts and finally have a control over sound you want to express! Doing all this in relax manner .... well,it is possible and when it is possible,it is beautiful to play all that crap.

:D
I think less is more is a good idea especially in the context of jazz where as you pointed out, the mix of instruments and harmonies is complex. Chic Corea has certainly used ring modulation but in a more heavy handed way but one way to cut down on the mix as you have said. The envelope follower of the low pass fooger can be used to modulate the mix of the ring modulator for example and create subtle changes in the transient.

Much of what I see in the demos for the foogers I do believe is do much over the top. Sure, it illustrates the effect but I am not sure that it shows how musically the foogers can be used even the freqbox which is considered all but untamable.

Lux_Seeker
Posts: 473
Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Thu Apr 30, 2009 4:42 pm

Dr_Floyd, thanks for the great list. Some of what you have one the list I posted here, some I was aware of but others I was not. You listed some of the great guitar synths of the past like the ARP Avitar. To me these were far superior to the MIDI based guitar synths of today which are running FFT programs on computers. Analoque pitch tracking is far different and to me much more musical.

Oscillators also track better than instruments. I would suspect that the industry went with the MIDI concept because once you have MIDI pitch bend you can bend any samples pitch. The trouble is that the bending sounds unnatural and not very musical to me. Every instrument has its own character and imposing the envelope and pitch envelope of a guitar on another instrument seems odd and unmusical to me.

Roland had a good idea with the articulation on the V-Synth and I hope that they continue along these lines.

Perhaps Moog Music can bring back the analogue guitar synth?

Vitja B
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Location: slovenia

Post by Vitja B » Fri May 01, 2009 9:58 am

Env. out would be good control,but for now it is not that useful for me, because it is not that wide like I would desire unless you open the gain knob
fully clockwise,but than you have a distorted sound and much hotter!
In this case you need few seconds to set everything and then again reset it...and few sec. means allot. Is there a way I could amplify a Env.out on LPF?
With CP-201 maybe?
MF-101,MF-102,MF-104Z,MP-201,PRS Custom24/10 top,Acoustic G100T,many more.

Vitja B
Posts: 42
Joined: Thu Apr 30, 2009 5:41 am
Location: slovenia

Post by Vitja B » Fri May 01, 2009 9:59 am

Sorry...CP-251
MF-101,MF-102,MF-104Z,MP-201,PRS Custom24/10 top,Acoustic G100T,many more.

Lux_Seeker
Posts: 473
Joined: Thu Mar 26, 2009 8:44 pm

Post by Lux_Seeker » Fri May 01, 2009 1:26 pm

I believe the attenuator on the CP-251 would do the trick if you have one.

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