MSB & LSB for half sharp Pitch Bend (Quartertone up)

[chikitin]

Hi,

I am trying to calculate the msb and lsb for half sharp Pitch Bend. For the pitch bend:

Now to increase the pitch of a note by 1/2 sharp! we need to change the pitch by the factor of 2^(1/24) or 50 cents.

I assume by default PSR-A3000 Synth bend up to +/-2 semitones. Since msb and lsb are the most significant byte and least significant byte of a 14-bit number.
So, 2^14 /8 = 2^11. Thus, lsb= '00000000' and msb='00010000'= 32. Is this correct?

Unfortunately, my DAW ( Cubase ), MSB and LSB range from 0 to 127 ( corresponding to 7 bit binary number) When send MSB= 32 from my DAW to a channel ( for duration of a selected note) to bend a note 1/4 tone up, it does not bend it correctly. What am I doing wrong please?

Any help would be greatly appreciated.

CS

[SeaGtGruff]

Does this help you?

http://www.elvenminstrel.com/music/tuning/reference/pitchbends.shtml

Also, I would recommend that you actually set the range in the program, rather than merely assuming it will always be set to +/-2 semitones.

[chikitin]

Does this help you?

http://www.elvenminstrel.com/music/tuning/reference/pitchbends.shtml

Also, I would recommend that you actually set the range in the program, rather than merely assuming it will always be set to +/-2 semitones.

Thank you.

My calculation is correct.

there are 8192/200 = 40.96 pitch bend units to 1 cent.

Therefore, 50 cents is equivalent of 2048 or 2^11. I will check the pitch range cubase is sending.

[SeaGtGruff]

Don't forget that the middle pitch bend value is halfway between the lowest and highest values, so if you want the note to be bent up a quarter-tone then you will need the value which is one-quarter above the middle value. If you're using absolute values, where the lowest value (note bent all the way down) is 0:0, and the highest value (note bent all the way up) is 127:127, you will need the value which is five-eighths above the lowest value.

MSB=000 : LSB=000 --> -2 semi-tones
MSB=064 : LSB=000 --> no bend
MSB=080 : LSB=000 --> +1 quarter-tone

That is, a difference of 64 in the MSB corresponds to 2 semi-tones, and a quarter of 64 is 16, so add 16 to 64 to get the desired MSB.

[Joe H]

My way of dealing with this issue is to set the Pitch Band range to + / -  one semi tone in the Mixing Console and just move the wheel / joystick a little to achieve the right amount of bend.

Joe H

[SeaGtGruff]

Some people use pitch bend as a way to achieve alternative scale tunings, and I get the impression that @chikitin is wanting to do something along those lines-- if not create an entire scale tuning (which can be done with XG events), then at least alter one note to get the half-sharp note.

[mikf]

Some people use pitch bend as a way to achieve alternative scale tunings, and I get the impression that @chikitin is wanting to do something along those lines-- if not create an entire scale tuning (which can be done with XG events), then at least alter one note to get the half-sharp note.

Maybe. But I'm with Joe, if he is just trying to pitch bend melody notes it's a very convoluted approach to a simple problem.

[chikitin]

Some people use pitch bend as a way to achieve alternative scale tunings, and I get the impression that @chikitin is wanting to do something along those lines-- if not create an entire scale tuning (which can be done with XG events), then at least alter one note to get the half-sharp note.

Yes, that is exactly what I want. My keyboard is supports XG-MIDI! I guess I shop be able to send these messages from Cubase. Is table 1.5 of the attached manual what I need to implement/follow?

Thank you very much!


[attachment deleted by admin]

[SeaGtGruff]

I haven't scanned the whole document, but the XG Scale Tuning addresses are shown on page App-14. Well, the full addresses aren't shown, but the last byte of the addresses are. There are 12 consecutive addresses, one for each note of the chromatic scale, in the same block as the addresses of most of the other multi-part parameters.

These 12 addresses let you tune each note of the chromatic scale within a range of -64 to +63 cents, where 0 cents is determined by the keyboard's overall fine tuning for Concert A. For example, if you were to change the overall fine tuning from 440.0 Hz to 432.0 Hz, then that would become the 0 cents tuning for A, with all of the other notes of the chromatic scale being based off of 432.0 Hz.

Thus, if -64 to +63 cents isn't large enough for some of the notes in your desired scale tuning, you might still be able to pull it off by adjusting the overall fine tuning such that -64 to +63 cents from the new overall pitch would let you attain the individual note tunings that you're looking for.

The practice of using Pitch Bend to achieve custom scale tuning is actually more flexible, since you can bend the pitch of each note over a greater range of cents. However, it's also much more cumbersome, because normally you would need to devote a separate MIDI channel to each note of the scale-- for example, use channel 1 to play all C notes (regardless of octave), use channel 2 to play all C# notes, etc. This is so you can set the Pitch Bend for each channel and then leave it alone, rather than having to apply Pitch Bend to each Note event, since that doesn't work as desired if you need to play different notes at the same time. Dedicating separate MIDI channels to each note of the scale lets you potentially use scales that contain as many as 16 different notes, such as C, C#, Db, D, etc., where C# and Db use different tunings.

Also, if multiple notes of the custom scale need to use the same tuning, they can share the same MIDI channel when using the Pitch Bend method. So in theory you could have custom scales containing many more than 16 notes. For example, if channel 1 were bent 0 cents, while channel 2 were bent up 50 cents, you could have a chromatic scale containing 24 notes using just those two channels.

By the way, the method of using Pitch Bend to attain custom scale tunings is normally used with keyboards or other MIDI devices that don't have the ability to use scale tuning messages such as are available in XG and GS. Also, the fine tuning message in GM (or GM2?) was modified long ago to allow each MIDI channel to be fine tuned, rather than just fine tuning the device as a whole. XG also has a message for that.

So you actually have a few different methods of attaining a custom scale tuning, and by combining two or more of them you have a lot of creative potential for attaining many different custom scale tunings.

[Joe H]

Michael,

Hypothetically speaking... you can achieve the results you describe, but as mikf has stated...  "it's a very convoluted approach to a simple problem".

Wouldn't be better to just learn how to work the Pitch wheel? which is actually "playing".

Another option to buy a PSR A3000 keyboard which has the capability for scaling.



Joe H

[SeaGtGruff]

Joe, I believe that both you and Mikf have misunderstood what the OP is trying to do. Granted, he hasn't been entirely clear about it, but he did verify that he's trying to play at least one note of the scale with a half sharp.

Pitch Bend affects all notes on a given channel, so unless you want to bend all notes being actively played on that channel by the same amount, using Pitch Bend is not going to cut it. That's why I pointed out that this trick of using Pitch Bend to get custom scale tunings normally involves dedicating specific channels to specific notes of the scale. It's an old trick, and I don't think anyone uses it anymore unless there's no other option. It's much better to use the scale tuning Sy*** messages which companies like Yamaha and Roland have added to their extensions of MIDI.

Anyway, I think the OP is trying to get the half-sharp note in a MIDI track, not while playing live.

On my PSR-E keyboards, Yamaha adds the XG Scale Tuning messages to the MIDI tracks when recording a song, even if the keyboard is using the standard 12-tone Equal Temperament tuning, in which case the XG Scale Tuning messages are all set to 0 cents. This is done as part of the normal keyboard setup, to ensure that the notes are tuned as expected. It's even done on the PSR-E433 and its predecessors, even though the scale-tuning feature wasn't added to the Function menu until the PSR-E443.

I would be very surprised if the XG Scale Tuning messages were not added to the MIDI tracks on the PSR-S, Tyros, and Genos models as well. Therefore the simplest way to record a song that includes a half-sharp note would be to record the song without trying to get any half sharps or half flats; just play the nearest note. Then go into the song editor, find the XG Scale Tuning messages, and modify the tuning for the specific note of the scale which needs to be a half sharp or a half flat.

If and only if that isn't sufficient for some reason, other techniques can be used. But as long as no more than 12 notes are needed in the scale, and as long as each note's desired tuning falls within the range of -64 to +63 cents, the XG Scale Tuning messages should be sufficient.

[Joe H]

Oh I understand all right.  I recommend he buy an A3000 and save himself a lot of trouble.

Joe H

[SeaGtGruff]

The PSR-A3000 is definitely a nice keyboard!

[SeaGtGruff]

You know, there's also an iOS app from Yamaha that lets you change the scale tuning, so I recommend grabbing that if anyone is interested in non-12TET scale tunings. I don't know why I didn't think of it before!

https://usa.yamaha.com/products/musical_instruments/pianos/apps/sound_controller/index.html

And while looking for that link just now, I found another new(?) Yamaha app that I hadn't seen before:

https://usa.yamaha.com/products/music_production/apps/faders/index.html

[SeaGtGruff]

I'm sorry, that Sound Controller app doesn't have scale tuning; the keyboard (which is for playing arpeggios) threw me off.

The app I was looking for is called Scale Tuner, and Yamaha says it's discontinued.

https://usa.yamaha.com/products/musical_instruments/pianos/apps/scale_tuner/index.html

What a shame, although it might still be available in some countries.

[chikitin]

Hi Jeff,
I have an old iPhone 4s just for that application and amplittube apps. Still works fine.

Thanks.