Flexor Audio to CV modules

[Eanna]

Hi, re-up'ing this post of mine from some time ago.
http://forums.planetz.com/viewtopic.php?f=9&t=31871

Further to the above, have you folks tried the Flexor Audio2CV modules? Here's some of them:
- Audio 2 gate
- Hyper Follower
- Pitch 2 CV / Pitch 2 CV II

All such modules are described on Roy Thinnes site here:
http://www.cwmodular.org/cv.html

Have any of you guys tried this with a bass guitar?
What kind of latency are we talking about?
Is it an effective "Midi Guitar" solution?

I understand that one of these devices cannot act Polyphonically, hence my original post above...

Basically, I have always wanted a more intuitive interface (for me) than a Keyboard, and while I really love what my Ableton Push does, a Bass is always going to be my "first instrument".
I have been member of the Yahoo MidiGuitar group for a few years, and other than the new Fishman Triple Play and the discontinued Axon series, nothing there has tempted me to spend money on that tech. And the focus there is always on the Guitarists - bassists don't really get a look in so much - and latency of tracking for basses with these devices is always highlighted, with their longer wavelengths etc. etc.
I know about the JamOrigin MidiGuitar VST (http://jamorigin.com/products/midi-guitar/), but I wasn't best impressed with it at a (very early) beta. It's gone thru many iterations of beta releases since then - I ought to revisit it - and tonight I see that they are working on a MidiBass product (!). It's cheap enough I guess - but you don't get any Scope Modular modules with it
My YouRock Guitar is fine, works amazingly well considering the price (polyphonic!), but it's just a cheap unit, and isn't reliable/responsive enough to be treated as a viable expressive instrument.
I'm aware of the ZTar line from Starr Labs, but they're very expensive, and don't have European Distributors still (afaik).
I'm also aware of the Eurorack "Entry Point" from Erthenvar (http://erthenvar.com/store/entrypoint), and sure it's tempting, but I still wouldn't be controlling my beloved Scope.

I don't own Flexor. And I know it kicks butt. But one of the butts I want it to kick is the Audio2CV stuff it offers.
Ideally, Flexor will bring, not only it's super modules, and its new flavours, but this ability to interpret monophonic audio too. One-off cost, and I add loads and loads of new modules, I get to try out Modular Patches like Faxinadu's that use Flexor, -and- I get a monophonic solution for controlling Scope stuff with my basses.

So if any of you guys can validate its butt-kicking abilities for following (a) pitch (with vibrato, and ideally anyone who has used it with a *Fretless*), (b) dynamics, (c) gating / spill, then I'm all ears......
And anyone there with any Midi Guitar / Midi Bass experience at all, please do share too.

[Eanna]

If no one has tried it directly, then maybe a bass loop from a sample pack over ASIO into the Flexor modules would be illuminating...

[Eanna]

Hi folks, up'ing this one again...

Anyone tried it? I'm very interested in your experiences and/or the results...


Thanks, Eanna

[borg]

I never saw a audio2midi patch for modular, but I had great results with alphonso's patch 'zing'. It is more a audio2freq patch with built-in synth.
It was on the adern forum, but that seems to direct you to facebook nowadays.
Used it on a project with oboe many years ago. worked great!

here's another one:
http://forums.planetz.com/viewtopic.php?f=16&t=24806 by MMCY

recently I tried Jam Origin's MIDI guitar, but didn't get very good results. Maybe I need to try different guitars/settings...

[Eanna]

Thanks very much Borg...

It's more that I would use Audio2CV to calculate the base frequency of the note.
From there, I get a Frequency, which I can use in the context of a Modular patch...
And I guess there are FrequencyToMidiNote modules too? (I should have checked).

I know that some of these tracking devices use a variety of techniques to find the fundamental frequency... Seems that the Audio2CV modules may have an implementation of some of this logic... But I am curious as to people's results.

As for your note on Alphonso's 'zing' patch, I'll have a dig. Since it was posted on the Adern forum, I'm guessing it employed the Flexor modules. That's good to know, and would add further weight to my interest in splashing the cash on Flexor.
An oboe is strictly monophonic, and I guess will have a clear fundamental frequency with that double reed, with not so many overtones? And the pitch will be pretty high, meaning theoretically faster tracking... But I'm delighted to hear it worked well for you...

And MCCY's device - looks like fun - I shall give it a whirl!

Personally, I really think that Scope's DSP atoms could be used to produce a very-decent-quality solution to the whole "Midi Guitar" issue.
Polyphony could be sorted by a hexaphonic pickup.

If Scope did manage something approximating a reliable Midi Guitar solution, it'd be yet another notch on Scope's bedpost.......

Some of the Midi Guitar crew out there spent thousands on this kinda stuff, and yet always find a reason to complain!

[jhulk]

bc modular also has the audio to gate and pitch modules

and yes they work its easy to test

just take a lfo output and put it to a square wave then put it into the audio2gate and then add an envelope and take the gate out to the envelope

set the envelope to a vca with an external audio input and take the output from the vca to the audio out

now you can use the lfo speed to trigger the gate which will trigger the envelope which attenuates the vca with the incomming audio

now use a control fader from bc modular and set it to hz frequency now you can use the mouse to change the speed of the lfo which you will get a stutter audio fx from the audio2gate and the envelope and vca

[fra77x]

I have the axon midi guitar. I don't use it often because synth sounds most of the time sound better played with a keyboard. (by my experience). Nevertheless it's cool for bass lines. I remember i got nice behaviour when i recorded with the axon in slow tempo and then i raised the tempo.

Back then i used a novation nova which offered 6 parts and i assigned each string to a different (mono) patch. I have done the same with modular patches also.

I will try to make a midi guitar algorithm someday. The most problematic part is to distinguise between different strings. That was the reason the axon offered a "hex" pickup.

[Eanna]

Thanks guys.

A quality monophonic creation for Scope would be a wonderful start.
Polyphonic is very-nice-to-have.

[fra77x]

I found that http://ubertar.com/hexaphonic/products.html

He offers hex pickups with individual outputs. That will require 6 input channels on scope. The rest is easy...

Regards

[Eanna]

Yep I referred to that same ubertar site in my original post above...

"The rest is easy"... if you know what you're doing

[fra77x]

Sorry i haven't read your whole post. I 'm trying now to create a monophonic algo. I will make it with a guitar i have no bass here.

Stay tuned.

[fra77x]

Do you want midi output?

[Eanna]

bc modular also has the audio to gate and pitch modules

I can't see them listed on his site... Sounds extremely promising... I'll dig tonight.
Thank you for your advice!

[Eanna]

Do you want midi output?

! Dude !
Wow thanks!

If you could, then that would be great!

[Eanna]

As for bass frequencies - if you're going for an FFT, you'll need lots of points to get to a resolution that goes down the bass frequencies...
So I was thinking of an Frequency Doubler / Octave-up effect before the detector circuit. Then a corresponding Frequency Halver on output...

As for tracking, I don't know how easy it would be to filter overtones... how you find the strongest as the fundamental...
I often thought that some compression tho would help the detector, to increase the 'strength' of the fundamental, but you'll need some kind of bandpass filter to help with noise.
A continuously-variable bandpass filter (high Q) scanning across the frequencies might work too, checking for the amplitude of the filtered output, to get a ballpark sense of current range...
Or a switch for bass/guitar.

As for triggering, and to reduce the number of false triggers, you'll need some kind of hysteresis algorithm.

As for Polyphony - I wouldn't know where to begin! But Monophonic would be a great start... but Duophonic would have most bass-playing eventualities nailed...
Wonder how those Polyphonic Tuners work?

Not sure its any help, but here's the config page for the JamOrigin software:
http://jamorigin.com/wp-content/uploads ... vanced.png
Doesn't appear that you have many controls over the algorithm there..

(I'm no expert in this stuff, and I know that a little knowledge is always a dangerous thing, so go easy on me....)

[fra77x]

http://forums.planetz.com/viewtopic.php?f=16&t=32490

[Eanna]

Cool. Thanks...

[Eanna]

One of these Adaptive Filters looks like a good idea too...

http://en.wikipedia.org/wiki/Adaptive_filter

Self-correcting, in theory... bit like a genetic algorithm too...

I wouldn't mind having to 'train' a neural-net type thing either.
I.e. play set sequences of midi notes, and let the error correcting component learn what my clean bass sounds like...

[fra77x]

As for tracking, I don't know how easy it would be to filter overtones... how you find the strongest as the fundamental...

If you lowpass the signal the result is the fundamental.

I often thought that some compression tho would help the detector

Not a bad idea

Or a switch for bass/guitar.

The main difference is the height of the pitch. Bass E: 41.204 Hz Guitar E: 82.41 Hz

As for triggering, and to reduce the number of false triggers, you'll need some kind of hysteresis algorithm.

Good idea. An env follower works.

Based in my tuner prework i think in 2 hours it will be ready. (monophonic midi output for now and most probably in general) Polyphonic signal is way complicated. You can track the pitch(es) but you lose the ability to know the start and the end of each string. A hex-pickup is definately needed for polyphonic work.

I have done some research at the past. Currently all "auto-tuning" guitars use a hex pickup. Only melodyne has improved the polyphonic analysis reaching 80% accuracy. He got a grammy for that stuff...

[jksuperstar]

An FFT has too much latency to be useful, and doubling/halving frequencies require memory delay-lines, also adding latency.

I use an Axon 50 with my Bass (5-string w/ low B). I find the only real issue is the lowest octave on the B string. everything else, especially if played with a pick, is low-enough latency to be playable. It also helps to have a synth with more than one voice...mis-triggers sound like *shit* if a note suddenly changes pitch on a monophonic synth, but having a second voice (or 1 per string) makes things much smoother.

With MIDI, you can also play an octave higher, and do the pitch shift in the MIDI domain...that is zero latency since you just subtract 12 from the note number.

I would like to use my hex pickup straight into an ADA8000, and use that in modular for direct-to-synth sounds. I've also recently been playing with the Pro-Wave, which has a modular shell for use as an oscillator. But it's still difficult for me to use 1 string per voice, so I have to instantiate a 5-voice synth, and lock down which oscillator gets which string. But I'm hoping to get a pile of info from the strings...envelope detect, pitch, energy, spectral content (upper harmonics), etc, and use that to add more dynamics to the synth sounds.

The old Roland GR300 did this for synthesis (not audio2pitch/midi): hard-sync a generated RAMP to the string audio...higher frequencies have lower amplitude. A compressor helps correct that, followed by filters & other synth stuff like AMP envelope (and/or envelope detector).