Pitch bend from a pedal

[zygor]

So the Roland EV-5 pedal works great for volume, but what's the connection / assignment / programing I have to do to get it to replace the pitch bend wheel on my Alesis QS7? Can anyone shine some light on this?

[JohnG]

First off, welcome to the MIDI tutorials forum, Zygor,

Hmmm! Now in all my years of MIDI I've never come across a MIDI pitch bend pedal!

The issue is, if you think about how to implement it, it would have to be a rocker pedal with its 'off' position dead central.
The likelihood is that, as soon as you put your foot on it, it would move off centre, i.e. instant sharp or flat.
It could be made with very strong centralising springs, but that would be self defeating because it would then be difficult, and strenuous, to bend.
No, I'm afraid you're stuck with the pitch bend wheel being just that, as are we all.
Unless, that is, you find out differently.
And actually it's nothing to do with MIDI, but an issue of control ergonomics.
(But a perfectly sensible question to pose here!)

Sorry I can't fix this one.
Kind regards,
JohnG.

[zygor]

Thanks John! It's nice to be welcomed. (and above grade, at this point;)

I get that the central position is zero, so that we can bend pitch up and down to values of plus 64 and minus 63, but isn't that just a relative way of saying that what we call 0 (the center position) is really a MIDI data value of 63 (or 64)? And the extremes above and below are data values of 127 and 0?

I guess along that reasoning (and yours as well) I would have to settle on first; master tuning the synth so that minus 63 (or 64, whatever) is my concert key, and second, the limitation of a one-directional pitch bend as a result, ie. the pedal position being zeroed at its "heel" position, with only positive values available toward the "toe". Yea? Nah?

[JohnG]

Hi Zygor,

First of all "yes" you get an extra star straight away, just for participating.
Many people, I know, just join to read my articles, and I have no problem with that.
But, when someone joins in, in my view they should be rewarded. What think you?

Next, on to pitch bend.
No, pitch bend is totally different to all the other MIDI controllers.
It doesn't have the normal range of 0 to 127 but, in the eye of the beholder, from -8192 thru 0 to +8191, or are the 1 and 2 swapped over?
Never mind, you get the picture.
It's held as a double 7 bit figure (14 bits), i.e. 0 to 16 thousand and whatever (do the math ).

Techie stuff.
The first byte of the MIDI message contains the 'pitch bend' MIDI message identifier and channel, then the next two bytes, minus the top bit of each byte, hold the pitch bend data. It's treated as a 14 bit field, but the centre value is treated as zero pitch bend, then actual zero as maximum negative pitch bend and 16,384 as maximum positive bend. (Or is it vice versa? I'll have to look it up.) Just as you surmised.

Another spoke in the wheel to understanding this, is that a set of MIDI RPN messages (more in another lesson perhaps) can be sent to the sound card (or synth or what-have-you) that change the pitch bend range away from its default setting of + or - 2 semitones, to almost anything you like, but usually just an octave, i.e. 12 semitones (plus and minus). This allows for such things as a slide up (or down) the neck of a fretless bass for instance. Most instruments I've come across limit it to a maximum of +/- 24 semitones, some less.

Not that that effects the physical controller which, of course, is analogue. It doesn't send digital data just a variable voltage.
But I believe (not sure about this) that an expression pedal uses a logarithmic potentiometer, whereas the pitch bend potentiometer is linear. I'll have to take my keyboard apart and check the pots! (No, not the AN1x again, nor the Novation X-Station, but the PCR-M30 perhaps.)
And that would affect very much how it works physically.


We might conjecture as to why pitch bend has so many 'more numbers' assigned to it than all the other controllers.
The answer is actually quite simple.
The ear is very much more sensitive (very much more) to pitch change than it is to say, volume.
I believe our ears work logarithmically to volume but linearly to pitch.
I'm not the person to ask why, it's a question of evolution I suspect.

That's probably sufficient for the moment, eh?

Keep 'em coming.

Kind regards,
JohnG.

[zygor]

Geez perfesser! I'm gonna need a bigger sodder'n arn!

Hmmph. Now don't go tearing into your keyboards yet. I'm just trying to do (more than?) my part in a four-piece 60's group of boomers, and would love to add a bit of slop to the sax patch without losing the left hand chords underneath. (Sax NEVER sounds natural without a little detuned growl and spit!) I'll pass your info on to my brother...now he's a REAL solder-jockey! Probably would understand that loga-rhythm-ic pot stuff too. I'll get back to you on this.
-Thanx
Vinny S.

[JohnG]

Jul 26, 2014 15:22:28 GMT zygor said:

Geez perfesser! I'm gonna need a bigger sodder'n arn!

Hmmph. Now don't go tearing into your keyboards yet. I'm just trying to do (more than?) my part in a four-piece 60's group of boomers, and would love to add a bit of slop to the sax patch without losing the left hand chords underneath. (Sax NEVER sounds natural without a little detuned growl and spit!) I'll pass your info on to my brother...now he's a REAL solder-jockey! Probably would understand that loga-rhythm-ic pot stuff too. I'll get back to you on this.
-Thanx
Vinny S.

Hah!

Like the "perfesser"!
Over at another place, where all this stuff used to be hosted (you'll see some empty threads where my stuff used to be), they got to calling me 'a MIDI guru'. But a religion MIDI ain't.

I used to be a data communications protocol specialist back in the days when I did a real job and before the grey hairs (what was left) outnumbered the brown. And before that I did an electronics apprenticeship in the aircraft industry working on VC10's and BAC1-11's. That's why this stuff is easy for me. Some of the protocols, in comparison, are horrendous. (I'm thinking specifically of ISDN 'D' channel, and using that across a 64kbps satellite link. Heavy stuff!)

And you're spot on about the sax. It ain't right without some slide.

Have you looked at e.g. the 'MIDI Solutions' footswitch controller? Google's you're friend here.
And now I think about it, I recall a similar discussion taking place on another channel maybe a dozen years ago.
I'll give it a bit more thought and delve into my archives.

Dons thinking cap!

On another tangent, going back to your original question, the foot controller is assignable on the QS series?
Now whether it could be assigned to pitch envelope to do what you're trying to achieve ...? Hmmm!
And just how well would that work? (Thinking aloud.)
Is there a copy of the QS7 manual on line?

Kind regards,
JohnG.

Added later:
Crikey! I'd forgotten just how programmable the QS series were. (Never owned one. Shame! )
Found the manual at the Alesis site and taken a first foray into chapter 8.
It'll need a bit more reading and figuring out.
Don't hold your breath.

[zygor]

So doctor,

I googled 'MIDI Solutions' footswitch controller and recognized those little black boxes as, well, "little black boxes" that probably solve a lot of guys MIDI problems. Step one for me is understanding what the problem "IS". So thanks! As soon as I know what it "does", I may dig deep for one.

But here's how far I've gone so far;
1.) Pulled up a (sustaining) organ patch
2.) Attached Roland EV-5 pedal jack to Alesis 'pedal 1' plug
3.) Entered 'Global Edit' mode. [EDIT SELECT] then [BANK >]
4.) Paged up to 'P12' 'Ped1 Ctrl#:__' which as expected, defaults to :#7 (Volume) (works as expected)
5.) Valued (up-down arrows) to 'Ped1 Ctrl#:4' (Foot Controller) And of course, nothing happens. No sound, nuttin'.

DOH! -brain just shorted-out....where's my list of ctrl #s?...am I programming the foot to control the foot?
IS there another controller # that should have an audible effect? Like #74 brightness or #10 pan?

6.) Tried both. No (apparent) change in either.
7.) How about #1? There we go! Leslie slow (heel) Leslie fast (toe). PROGRESS!

And I never left Global edit mode, and also don't intend to [STORE] that setting. But I have a (momentary) off/on switch around here. Maybe later.
(Also Jeffrey Rona's book lists Ctrl #4 as Foot Controller but describes it under the paragraph "#3 FOOT CONTROLLER" ... oh well.)
So foray away and I'll test out any of your hypthesesis on the Alesis.
-Vince S.