Diphonizers consist normally of two paralled filters. http://physics.indiana.edu/~p105_f02/vowel_recognition.gif shows the frequencies associated with the 2 filters, for various vowel sounds. And shows that to get all (or most) with a single control, would require a way to move around the space shownb there. One way might be to have a single pot (YEA!) generating a voltage, which is transformed into two separate voltages (one linear, the other U or V shaped) which then control two VCFs. That way with one sweep, you can cover an interesting range. I think this might be covered in the Geofex Wah history?? NB I know nothing specific about the Colorsound unit.
He certainly does spend a bit of time on the vocal quality of wahs, and a bit more time on how to make them more vocal and vowel-like.
I'm more interested in seeing how the Kent/Schaller Yoy-Yoy type dual inductor or even a parallel twin-t would work in an EF. Of course, it also never hurts to see how people overcome certain inherent design deficiencies.
Having never even heard one of these, I'm also interested in hearing the vowel frequency switching design; whether electrical (RG) or mechanical and its counterparts (Yoy-Yoy or equivalent parallel setup).
The Schaller/Kent Yoy-Yoy option on their wah is one of the niftiest sounds I've ever had the pleasure of owning (and one that I deeply regret selling). If good wahs sound "puke-ey", a decent Yoy sounds "pout-ey" (as in a 9 year-old taking a temper tantrum).
Confirmation of the existing posted schematic (courtesy of Stellan Lehrberg), and inductorless attempts at mimicking it or extending it (for example envelope-controlled versions) will be deeply appreciated.
There comes a point where sweeping a bandpass filter just doesn't seem like enough.
I'm more interested in seeing how the Kent/Schaller Yoy-Yoy type dual inductor or even a parallel twin-t would work in an EF
After receiving some excellent advice from Tim E last year I did some (still am doing some) messing around with twin Ts.
I paralleled a couple of filters and controlled them with an envelope follower. Although definitely a wah, it sounded more like a phaser at times. It had a throaty sound to it (I nicknamed it 'Sweep Throat') which you don't get with a single filter!
I'd do it very differently now, but the idea is worth toying with - you can get some interesting effects.
"They always say there's nothing new under the sun. I think that that's a big copout..." Wayne Shorter
Playing with the two parallel filter idea, I found that simple Twin T/bridged T circuits leave something to be desired. Mostly because, to my ears, they behave more like resonant lowpass filters than bandpass filters. Changing to a Multiple Feed Back (MFB) bandpass filter yielded nicer results, as the output seems to be a "better" bandpass response.
The downside to the MFB filter is that gain is greatly reduced as the filter is swept up, which leads to some hack-ish things in order to compensate. Ultimately, I think a much better way to do this would be to use at least two parallel state variable filters in bandpass mode.
I would be very interested in how Colorsound and EHX did this.
As part of the ludwig follow up, I have a design for a dual filter that does some of this, I think.
I didn't like the twin t or LC filters I messed with. The one that seems to work OK is the state variable.
I have a design in the proving stages with two filters. Each filter is one LM13700 dual OTA, and the nice thing is that you just hook the control pins in parallel and you can think of it as one filter chip. You get either linear or exponential response depending on how you drive the control pins, and it will go from subaudio to ultrasonic in a single filter if you really want to, as well as Q's from about 1 up to 20 or so.
A single LM13700 makes a pretty good wah by itself, as you can include a clipping feedback on the filter itself.
I'll put the schemo up as soon as I get a chance.
Every single NASA manned mission starting with the Gemini series has carried a roll of duck tape. Yes, really. Look it up.
Reviving an old thread Found the Colorsound Dipthonizer schematic incredibly difficult to decipher, so here it is - updated with legible values and mods:
Special thanks to Dino for uploading this, really appreciate it man!
Still unverified, but have compared it to plenty of boards and layouts so it should be good to go. Gonna start breadboarding it within the next couple of days... If anyone spots a mistake or three, please let me know!
Toneman: Didn't miss it no, that was me Thanks for all your work man, amazing stuff! All I did was update the values and mods against the schematic... I'm nobody really. The original schem was giving me a headache
Jimi: Just add - /viewtopic.php?f=19&t=2007&start=160 - after the "other forum"-address
the dipthonizer and vocalizer both use MFBF (MultipleFeedBackFilters). tedious to tune cause U are supposed to keep the cap values the same. my 2 dipthonizer builds are working, but don't sound right yet. I am starting to tweek the cap values notice the cap values of the EH Talking filter.....slightly different...... shooting for something inbetween..... thinking about adding a rotary switch similar to the MeatBall..... The MeatBall uses MFBF also...... will post more info if/when I succeed
Hmmm, direct links to the "other forum" seem to be blocked.... copy link, paste link, remove "*", then press return. U will have to be logged in to view images..... this is where ALL the info is.......
I am such a loser, after playing around with Bassballs on breadboard, and having good results like Pedro in post 6, then wanting to try more circuits so ordered 5 more breadboards from ebay, wondering whether to do a Colorsound Vocalizer, or Dipthonizer, or ehx Q-Tron, or ehx Talking Pedal, then out of the blue I bought an ehx talking machine from ebay last night. Damn! What was I thinking...i dunno i couldn't help myself...
Interesting to see all the filter heavyweights posting on this same subject in 2004. What those guys must know now, and they still share, I for one really appreciate it. The vowell sound pedals just fascinate me no end, a wah pedal has been part of my sound forever, I always wanted a voice box, I saw one in 1982 for sale but couldn't afford it, money was scarce back then.
One of the experiments I started thinking about on the busride this morning was using an expression pedal to foot-sweep one of the filter sections in the Bassballs. The transistor that is used like a voltage-controlled resistor to ground to sweep the centre-frequency of each bandpass filter section is in parallel with a 47k resistor to set maximum resistance. It is a trivial matter to set the trimpot for one of the filter sections so that it doesn't sweep in response to envelope, wire up a jack for an externally controlled variable resistance, and either place that resistance in parallel with the 47k resistor, or replace it, using a jack that will switch the 47k out. This would let you have one section that sweeps upward in response to picking strength, while you sweep the other one down in the fashion you want.
As is, appropriate trimpot adjustment on a stock unit can get you some vowel-like sounds. being able to control both the direction and differential sweep if the two filters should be able to get one close to formant movement. And of course, since you still have the option of using envelope control over the transistor in tandem with a foot-controlled resistance for that filter section, there are a lot of possibilities.
Colorsound Vocalizer, or Dipthonizer, or ehx Q-Tron, or ehx Talking Pedal
I've been tempted to try my hand at the ehx Talking Pedal, using either LDR's to fake the "unobtainium" pots, as per ToneGod's Rock N' Control. There is also a thread somewhere here outlining replacing the pots with trannies, IC's, and trimmers (complete schematic is there). Guess that's the "sucker-for-punishment" in me
BUT... is it really worth it? I've listened to some clips, including pot work arounds, and it doesn't really seem to be THAT impressive. I think that either the Dipthonizer, or Vocalizer (to a lesser degree... if we can get it working!) would be more "interesting"? I must admit though, I've been spoiled of late. The Humanizer on my GT-PRO is in a league of it's own. But, I digress.
Honestly, keeping to DIY territory, I say the Mold Spore wah would be a much better build if one is looking for trash-mouthiness. Less of a one trick pony. This video reall got my attention;
If there is interest, I don't mind tackling a vero of the Mold Spore. Something that fits into a Crybaby shell.
"No matter how many times I cut it.... it's STILL too short!!