Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
Posted: Mon Nov 03, 2008 11:48 am Post subject:
Actually I at this very moment am working on entering the 21st century - I just came upstairs from recording my first video of the Appendage and saw this post!
Got the video down, but the audio is a bit sucky - my camera has no line input, so I recorded it with the D8 recorder while I took the video. Now I gotta figger out how to dub and sync it up.
Bill's got a PCB laid out component-wise and is working on getting the tracks to fit. _________________ My Site
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
Posted: Mon Nov 03, 2008 1:23 pm Post subject:
If you can forgive the crappy audio, here's a movie of the Appendage in action.
It starts out using Initial and TFS voltage on the mix output to control pitch. The initial holds the voltage at the initial point of contact, and it requires two pressure points to bend the voltage. Sliding one pressure point varies the cutoff of the filter, which is being controlled by the slide voltage and the EG.
Later on, I introduce external modulation (a pulse LFO) to the Appendage. Then I back that off and add a tiny bit of bend voltage to the mixed output. This is the dying whale portion.
Then I add a lot of bend voltage to the mixed output, then, towards the very end, add some autoglide to glide the hammer-ons.
As I mentioned before, the audio sucks. The ka-chunk-ka-chunk heard in the background at the beginning is the D8 recording. I just haven't quite figured out how to dub the D8's recording in over the crappo mic audio, but I'll get there. Eventually.
I joined this forum for the sole fact of praising you for the Appendage. I just read all 10 pages, half of it I don't understand as much as I'd like to, the other half I dont understand at all, but from what I can tell it looks awesome.
A kind gentleman from another forum linked me here as I've been looking around to make a tannerin-esq instrument. This goes above and beyond that. Hopefully another read through with referencing to google every other post will help a bit
Joined: Apr 17, 2006 Posts: 2810 Location: New York
Audio files: 24
Posted: Mon Nov 03, 2008 6:00 pm Post subject:
Scott,
Totally consuming video ! Well done and you REALLY DO get a feel for what this instrument can do when you see and hear it in action. The sound actually was very good to be honest. No bad at all. As Chris said, no apologies necessary for the sound.
OK, back to the Appendage PCB layout .............
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
Posted: Mon Nov 03, 2008 8:48 pm Post subject:
Well, thanks guys!
And thanks to Bill, too. He's the one that's been dragging me kicking and screaming into the world of new-fangled computer technology (for me, new-fangled is anything higher than a 286 and DOS 5.0).
That patch was just one of many that can be accomplished with the mix section. I was in a hurry when I posted before, so I'll explain a bit about it:
The mix section mixes four voltages together, along with any external modulation, and a direct voltage input if you should have one applied (I just had external modulation on this one, which was that little bit with the pulse LFO). The four voltages are Initial, Bend, Slide and TFS. There's also a coarse and fine offset control so you can adjust the general pitch up and down.
The range of the pitch section just depends on how you have these pots set. In the first part, I just had initial dialed up very high and I had the TFS voltage dialed up so it also was contributing. The initial voltage is determined by wherever you initially touch the ribbon. The TFS voltage rises from 0V all the way up to 10V (max, depending on how much you have mixed in) when you have two pressure points (two fingers) pressing the ribbon - the farther apart, the higher the voltage goes, and, with it mixed in and controlling the VCO in this case, the higher the pitch. So, with this mix, the pitch stays constant as long as you have the ribbon pressed at only one point. In actuality, with a very high mix of TFS, the pitch can even vary depending on how much pressure you're applying, because the width of your finger can qualify as two pressure points (left and right edge of the finger).
Anyway, the slide voltage output, which goes from 0V to 10V was controlling the filter cutoff, so pressing at one point and sliding without removing the pressure held the same note, but opened and closed the filter. Only when the second pressure point was applied did the pitch change without first removing and reapplying pressure at a different point - this makes it so you can hold one finger and slide or hammer-on the second to vary the pitch and the filter at the same time. It depends on where you start and where you end up, if that makes any sense....
The TFS only cares how far apart the pressure points are, so you can slide a pressure point up or down relative to the other point and have the pitch go in what might look like a counter-intuitive direction (it's not nearly so if you're actually playing it). For example, right around 2:00, the TFS is stretched high, but the note started very low (initial voltage), so when the *lower* (left hand) pressure was removed, and the remaining pressure was the right hand (higher), the pitch dropped back down to the low note, because the initial voltage stays constant as long as pressure is applied - the second pressure point was removed, so the pitch went *down*.
Anyway, TFS doesn't have "memory" like Bend, Slide and Initial have, so as soon as you remove your fingers, it goes back to the last initial note value. Usually I use TFS for some other task - like changing timbre or controlling a VCA to introduce FM, but it can be really expressive when using it for pitch control, too.
This is one instance where two pressure points changes the timbre or pitch. This was in voltage mode - in current mode, two pressure points can work in a different manner without using TFS; with the "lower" pressure point dynamic and the "upper" pressure point doing something else. I'll put that into a video
Anyway, I added in a small amount of bend voltage after the external modulation section - that's the spiffy thing about the mix - you can set any ratio of initial to slide to bend, which determines how responsive the ribbon is to the amount of horizontal slide. With just a little bit added, you get the lower bends that are good for "warping" things. With a lot of bend, it becomes more violin-like (for want of a better term). With bend and slide added together, it becomes sharp as a whip, so, when you have it blended with initial, you can hit a note and really bend the crap out of it just by wiggling the finger.
The autoglide just glides between hammer-ons, but doesn't lag initial notes, which is what it's intended to do. It's nice for really exaggerated "bends" by actually hammering on rather than sliding. It affects bend and slide, but doesn't affect TFS, which comes from a different place in the circuit.
The voice, BTW, was just a sawtooth through the Late MS-20 Clone high pass (to add harmonics, sort of like Ian's Threeler does, but not nearly as versatile as the Threeler), and then through the 2040 clone filter, through a VCA, and, of course, the delay. The Gate and Trigger outputs of the Appendage were controlling the EG. The mix output was controlling the VCO and the Late MS-20 filter clone so it would "track" the harmonics.
Congrats and Kudos. Thanks for the video. I must say I am more than smitten Now!! This controller is will bring about new forms of expressions and Music.
Joined: Mar 22, 2005 Posts: 363 Location: Boston
Audio files: 1
Posted: Tue Nov 04, 2008 9:41 am Post subject:
Amazing stuff, Scott... Great job! I'm really excited about this one.
I've already got a 500 mm softpot awaiting its call to service.
and now to watch that video several more times...
This is really ANOTHER very cool innovative design that you have come up with!!! I have been watching this thread for a while and the video does a great job at showing it's capabilities. I purchased the Softpot strips and will probably be perfboarding the circuit soon. I need to pick up some LF398 ICs.
Cool video, it demonstrates all the words I read here quite well I think. I'll need one ( ... or four ... that would make a violin ). _________________ Jan
also .. could someone please turn down the thermostat a bit.
The long force sensor, when laid underneath the SoftPot would probably work, but I don't know how well (I've never tried it out). I didn't go for it for a number of reasons - I'm not sure how much resolution it would have (could be fine, I dunno), it's hard to find (this is the only place I could find that had the stuff), and I (personally) am not sure how well I could lay out a strip of it, and adhere a softpot over the top - it would have to be aligned as perfectly possible, so it was directly underneath the SoftPot. "Perfectly" isn't in my mechanical build vocabulary.
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nice looks like you can have a fun time with this good work!
I have been watching this thread for a while and the video does a great job at showing it's capabilities. I purchased the Softpot strips and will probably be perfboarding the circuit soon. I need to pick up some LF398 ICs.
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