FTP pitchbend data with whammy bar vs left-hand bends

Started by Vaultnaemsae, March 24, 2023, 02:00:11 AM

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Vaultnaemsae

So, in a moment of inspiration I whipped the old FTP off my Godin Multiac Jazz, removed the GK3 pickup from my headless DeLap custom and replaced it with the FTP.

I haven't worked with the FTP on a guitar with a whammy bar for years (a Steinberger TransTrem no less).

FTP is set to hardware mode, "Smooth" at +/-12 semitones with appropriate pick/dynamic settings. Straight-ahead pitch tracking is superb and left hand bends of a semitone are registered rather beautifully. Excellent.

Now if I try to execute a slowish pitch dive with the bar I'm not getting a smooth pitchbend data stream...it defers to a new semitone as if in "Stepped" mode.

Any suggestions for bar use with FTP, etc.?

BTW, I'm experiencing the same with MIDI Guitar 2. The only way I can get reliable controlled pitchbend is with an external MIDI controller sending PB data. I saw Nickjitsu approach his FTP setup this way in a YouTube vid from some years ago when I was searching for a solution today. He sends in PB data with an expression pedal. I'd rather do it with my hands...



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FishmanSoftware

Quote from: Vaultnaemsae on March 24, 2023, 02:00:11 AMSo, in a moment of inspiration I whipped the old FTP off my Godin Multiac Jazz, removed the GK3 pickup from my headless DeLap custom and replaced it with the FTP.

I haven't worked with the FTP on a guitar with a whammy bar for years (a Steinberger TransTrem no less).

FTP is set to hardware mode, "Smooth" at +/-12 semitones with appropriate pick/dynamic settings. Straight-ahead pitch tracking is superb and left hand bends of a semitone are registered rather beautifully. Excellent.

Now if I try to execute a slowish pitch dive with the bar I'm not getting a smooth pitchbend data stream...it defers to a new semitone as if in "Stepped" mode.

Any suggestions for bar use with FTP, etc.?

Based on your description, the problem is likely that you are in single-channel mode (aka Poly Mode) which in the case of TriplePlay, you can only get bends to work when a single note is playing. Once there is more than one string playing, it automatically switches over to a behavior like "Trigger" mode.

If you use multi-channel mode (aka Mono Mode), then each string can bend independently, which then allows more natural bends, i.e. whammy bar will work as well as bending individual notes while playing a chord.

To be clear, the connected synth has to properly support multi-channel mode, so if the connected synth only supports a single channel, or is in Omni mode (where the channel info is ignored) then it will not play properly in Mono Mode, so in those cases you are stuck with Poly Mode and the bend limitations I described at the top.


Vaultnaemsae

Quote from: FishmanSoftware on March 24, 2023, 07:36:21 AMBased on your description, the problem is likely that you are in single-channel mode (aka Poly Mode) which in the case of TriplePlay, you can only get bends to work when a single note is playing. Once there is more than one string playing, it automatically switches over to a behavior like "Trigger" mode.

If you use multi-channel mode (aka Mono Mode), then each string can bend independently, which then allows more natural bends, i.e. whammy bar will work as well as bending individual notes while playing a chord.

To be clear, the connected synth has to properly support multi-channel mode, so if the connected synth only supports a single channel, or is in Omni mode (where the channel info is ignored) then it will not play properly in Mono Mode, so in those cases you are stuck with Poly Mode and the bend limitations I described at the top.



Thanks for chiming in.

I'm focusing on playing single note lines so the mode doesn't seem to be the issue. But yes, I'm, in "Poly Mode" and I tried both modes anyway and the performance is basically the same -- under single note conditions.

I originally tested this using Omnisphere 2 in Standard and Live modes to match FTP's "Poly" and "Mono" MIDI channel settings respectively.

Setting the PB range to +/-24 semitones (obviously matched in synth) seems to very marginally improve bend performance but it's rather ambiguous whether or not it actually has any significant effect.

The first semitone of a whammy bar-initiated bend is fine especially if it's within a very short time frame -- say 1 to 1.5 seconds. It's when you continue to bend that sustained note that the PB data becomes stepped. You can observe the pitchbend data in a MIDI monitor -- it appears quite staggered compared to data from a pitchbend wheel.

I suppose this is a limitation of the technology and the player simply needs to get what they can out of it.

I'm thinking I might set up an up/down pressure button on the SoftStep 2 to send PB and CC data simultaneously -- so it can control a synth and whammy-type effect at the same time -- see if I can do away with using the bar for pitch expression altogether.

 
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admin

Review the developer Andras Szalays
 MIDI GUITAR FAQ

http://www.panda-audio.com/midiguitar.php


MIDI Guitar FAQ
I spent most of the last thirty years designing guitar synthesizers. I developed several generations of devices from the Shadow GTM-6 / SH-075 through the Blue Chip Music / Terratec Axon until the Fishman Triple Play today. Over this period I answered thousands of questions from users who had some difficulties to understand certain features or behavior of their devices. Now, as I have here a web page of my company, Panda-Audio, I want to take the opportunity to summarize this information in the form of an FAQ. I hope I can help users of guitar synthesizers a better understanding of their devices with this information. While these answers are based on my designs, I believe most of the information here is true for Roland or other devices too. I will update this page time to time with questions whatever I recall from my memories, or whatever new questions arise.

Andras Szalay

Q: Why do most guitar synthesizers have an option to send the six strings on six separate MIDI channels? E.g. you can play polyphonically on a keyboard without restriction on only one MIDI channel.

A: When a note is started in MIDI the pitch of the note is determined by the note number of the Note On message. This pitch can be changed afterwards only with Pitch Bend messages. When you play polyphonically on a keyboard and you use the pitch bend wheel, it will bend all notes what you play by the same amount. In opposite, on a guitar it is absolutely natural that the pitch of individual strings can change individually, independently of the other strings. Since in MIDI the Pitch Bend message is common for all notes on a MIDI channel, individual pitch control of the notes for individual strings can be solved only if each string has its own separate MIDI channel. As a painful compromise it is possible to use pitch bend on one MIDI channel as long as the guitarist plays only a monophonic melody, and turn off pitch bend when he changes to polyphony. However, this can lead to contradictions that cannot be resolved in certain situations, e.g. when the pitch of a note is changed, and this note is sustained while another note is suddenly started. In this case, at the start of the second note the first one will have to return to its starting pitch, or it must be shut off early.

Q: OK, I do not bend the strings, so I could not care less. Then can I use my guitar synthesizer on one channel without compromises, yes?

A: No. A very important part of expressive guitar playing is legato. Guitarists very often do not pick every note of a melody, but notes get different accent if they are picked, or if they are played with hammer-on or pull-off. A guitar synthesizer can emulate this also with Pitch Bend. Although a special Legato Mode is part of the MIDI specification, most synthesizers did not implement it, so the safe way is to use Pitch Bend instead. Then we are at the same point as in the question before.

Q: OK, I do not use hammer-on and pull-off, I pick every note. Then I really do not need Pitch Bend, so I can use one channel only, right?

A: No. There are at least two important arguments why Pitch Bend should be used even if you pick every note.

Coordination of left and right hand.
If you play an ascending scale on a string, theoretically you should press the string to the fret with your left had finger (I mean this for right handed guitarists) exactly at the same time as you pick it with the right hand. Of course, this is only theory. In practice this can never be coordinated perfectly. If you are too early with your left hand, then you get a hammer-on to the new note first, and then a little bit later the note is picked. Even worse if your left hand is too late, then there is a chance that you get a damped note, because your finger already touches the string, but does not press it to the fret yet. To avoid the second situation which is much more annoying, guitarists play a little bit ahead with the left hand compared to the right. The question is how much, and how stable is this difference. When I analyzed John McLaughlin's test recording, it was amazing to see that pitch changes (left hand) were always just 5-10 msec ahead of the pickings (right hand). By average guitarists this can be 10 times more. Now, when the guitar synthesizer is sensing a hammer-on (which is not intentional in this case), and Pitch Bend is enabled, then it follows the pitch in a natural way, and then when the new note is picked additionally, it starts a new note at that pitch. In opposite, if Pitch Bend is disabled, then during the hammer-on phase the guitar synthesizer does not know that soon a new pick is following, so it starts a new note with a low velocity value. But very soon the new picking is coming (with a higher velocity value), and this results in an annoying double trigger.
Unintended pitch change of the sound.
When you pick a string, at the very beginning the pitch is always more or less higher than the intended pitch. I mean "intended pitch" here the pitch of the string as it is sustained for several seconds. This is where you tune the string to your reference. There are several physical reasons why the pitch at the very beginning is higher than the sustained value, sometimes by more than a semitone.
One of the reasons is well known in classical physics: the pitch of a string vibration has a steady frequency only if the amplitude of the vibration is negligible to the length of the string. If it is not negligible, then the vibration causes an increased average tension in the string, and higher tension means higher pitch. This effect depends on two factors:
the tension of the string: thin strings have lower tension for the same pitch, so can be played with much higher amplitude, thus the pitch deviation is higher as well.
the harder you pick, the higher is the deviation.
There is another reason for unintended high pitch in the attack. The short picking pulse that started from your pick is propagating towards the point where you fretted the string. However, if the pulse is large (you picked hard), and the string deviation is large (light gauge string), and the string height is low, then the pulse slightly hits the fret that is one higher than the one that you fretted, simply because the string is so close to this fret. This results a reflection from this fret that appears in the first vibration cycle as a one semitone higher note. This happens only in the very first cycle of the vibration, since the amplitude of the pulse gets very much smaller even by the second reflection.
It is of course natural, if you do not get this problem with a Roland, since it does not recognize pitch from the first cycle anyway. Also, it is good to know that if you turn the pick sensitivity to finger picking, it will skip recognition in the first cycle, so this problem will probably not happen. With this knowledge, here are some tips how to eliminate this problem:
First and most important: Even with a piano sound it is not necessary to play in Trigger mode. If you use Quantize to semitones then you get just as well quantized pitch like in trigger mode, but these glitches at the very beginning of the note will not be audible, if the synth has a good and fast response. Of course, this works really well only in MONO mode, on six MIDI channels.
Use medium or hard gauge strings, no light or extra light.
Adjust the string height to be as high as you can tolerate.
Play softly, do not pick hard.
Play with the tip of the plectrum, not with the flat part
Finger Picking Mode, if the slightly slower response does not hurt.

Q: When I use Trigger Mode and I play a hammer-on, then I understand that I get a new note, but why is it slightly delayed?

A: See the first part of the previous answer about left-right hand coordination. In order to avoid a very annoying double trigger, when the system recognizes a hammer-on while in Trigger Mode, it will intentionally delay the new note, waiting a little bit if a new picking is coming or not. It will trigger a new note based on the hammer-on only if the picking does not come in the expected time Frame.


Vaultnaemsae

It's always useful to review such information and compiled documents, so thank you. But anybody reading this thread in the future when they encounter the same issue should know that neither of the linked items addresses the specific issue I raised above.   
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Brak(E)man

#6
Did you have the same problem using GP-10 or vg99 gtm and bends vs whammy bar ?
I've never had the issue, either on a midi guitar or a GK going into gtm conversations.
(Even fretless has worked fine , which can take you up to +/- 24 semitones.)
Have you tried thinning out the pitchbend data ?
If I understand the problem, the pitchbend data comes in "clumps" ?
I haven't really used FTP or MidiGuitar that much, since more or less giving up on midi.

Just curious.
swimming with a hole in my body

I play Country music too, I'm just not sure which country it's from...

"The only thing worse than a guitar is a guitarist!"
- Lydia Lunch

admin

Quote from: Vaultnaemsae on March 25, 2023, 07:54:03 PMIt's always useful to review such information and compiled documents, so thank you. But anybody reading this thread in the future when they encounter the same issue should know that neither of the linked items addresses the specific issue I raised above.   
make a short video demonstration of your issue

Vaultnaemsae

Quote from: Brak(E)man on March 25, 2023, 11:55:18 PMDid you have the same problem using GP-10 or vg99 gtm and bends vs whammy bar ?
I've never had the issue, either on a midi guitar or a GK going into gtm conversations.
(Even fretless has worked fine , which can take you up to +/- 24 semitones.)
Have you tried thinning out the pitchbend data ?
If I understand the problem, the pitchbend data comes in "clumps" ?
I haven't really used FTP or MidiGuitar that much, since more or less giving up on midi.
Just curious.

So to be clear...FTP's pitch bend works VERY VERY well in very short burst situations. Just, if I hold a note and a little more slowly bar dive it, the pitch bend info gets confused and seems to reset as the guitar's pitch passes the next semitone down point. So that is sort of the "clump." It's a limitation but one that I can work with.

I don't recall having this with the VG-99 but that doesn't mean much as it didn't really matter to me until I started hearing it with the FTP. I'll have to reinstall the GK on my guitar to double check performance but that will be a major operation so I'm saving it for another day. At this time, I'm leaning away from working with 13-pin gear for a while (again) as I feel like things have become a bit over complicated.

You know, you get into playing an instrument and reacting to it and you see what you can see, find ways to make it musical. I'm actually very happy with the FTP now. I did struggle with it in the past but that's pretty much all cleared away. I was just playing with it for 90 minutes solid and really finding a good interaction and comfortable feel with it.

BTW, I reset it at +/-2 semitones so I could try it with the KORG Odyssey and a couple of the Arturia V Collection synths that don't have adjustable PBR and it was simply nailing it. I think I need to retract my suggestion about bigger PBR performing better.

I'm not sure how to thin PB data with FTP -- easy with Roland/BOSS though.

Quote from: admin on March 26, 2023, 05:57:21 AMmake a short video demonstration of your issue

That's a great idea. While I was playing just prior to writing this I was audio/video capturing it all cos I wanted an FTP reference point before reinstalling the GK3 for testing but ScreenFlow crashed when I ended the session and I lost all that great footage. So, I'll have to come back to it later.


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shawnb

My theory is - as lots of these issues are - pitch bend range, PBR... 

If you exceed the PBR range (via note bend, legato, or whammy, or slide...), it will trigger a new tone and reset the PBR to 0.  That's the only way it can maintain the proper tone/frequency.  You will absolutely hear when it resets, as most synth voices use different timbre for notes vs legato.  It will stutter.

Neat trick: You can use this to determine the PBR on your FTP (or any guitar-to-midi device) without the app:  Use a synth bell voice on your synth, something clear & percussive.  Using a slide, start very high up the neck, pluck an initial tone, then slowly slide all the way down the neck.  You want to hear a continuous drop in frequency...  But if you have a low PBR, a new tone is triggered every time you exceed the PBR # of semitones.  So...  If the bell rings every 2 frets, the FTP's PBR is set to 2.  If the bell rings every 5 frets, the FTP PBR is 5. 

You can see this in MIDIOX if you have it.  If you don't have MIDIOX, record the MIDI stream in your DAW.  You will see occasional notes, followed by wheel events descending from 0, and the pattern repeats every time the max wheel event value is exceeded.

(I am pretty sure the Roland gear MIDI out does the exact same - but it's been a very long time since I've used MIDI out on Roland/Boss gear.) 

But that's only half the problem.  You may be wondering how you could possibly exceed 12 or 24 semitones...  Keep in mind that wheel events are used for all bend/legato/whammy/slide...

So with a whammy it is VERY EASY to exceed the PBR when you factor in legato, even with a PBR of 24:  Pluck a note on the 12th fret, then do a pull-off.  Your lower tone now comes from your initial note plus a -12 semitone wheel event...  Dive on the whammy.  It will reset when you pass another octave. 

So, my theory is that you are in fact exceeding the PBR, when you combine legato + whammy.

I use slide & whammy all the time, which is why I always have the PBR set to 24, the max value.
Address the process rather than the outcome.  Then, the outcome becomes more likely.   - Fripp

shawnb

...And never forget the primary rule: the PBR on the FTP should match the PBR on your synth (unless you are deliberately aiming for theremin-like effects & sour chords....)
Address the process rather than the outcome.  Then, the outcome becomes more likely.   - Fripp

admin

Quotedon't recall having this with the VG-99

For its internal sound generation- Zero guitar to MIDI is employed on VG-99, therefore perfect performance of all guitar techniques, and MUCH lower latency

Details
https://www.vguitarforums.com/smf/index.php?topic=14088.0