Aftertouch

[jmg8]

I need help with this one please.

Think of a patch that is a simple saw OSC with aftertouch modulating vibrato depth.
When playing the keys normally would you expect to hear any vibrato effect?
Should the vibrato start right away with the initial strike of the key?
Should the vibrato only start when the key is already held and additional pressure is applied?

Please do not comment on the existing implementation of Melda synths.
Instead please comment on the expected behaviour and your experience of how it has worked in the past with other keyboards/instruments.

Thanks.

[zerocrossing]

It’s nothing to do with the implementation of aftertouch in the synth (well, not Melda synths) it’s how you implement it, and you can implement it any way you choose.

[jmg8]

I know that, I have chosen to implement it as described above in the hypothetical patch.

[DarkStar]

From here
https://support.roli.com/support/soluti ... ftertouch-
Aftertouch can start at the same time (strictly immediately after in event terms) as the Note On. I think that it would be most sensible to start with an AT value equal to the Note On velocity.

So, send an AT straight-away with vlaues higher or lower than the velocity.

[DarkStar]

This prompted me to do a few experiments: using AT to modulate the OSC volume:



And:



(Where did I get those red guide lines from? Just drag them off the top edge of the graph!)

[jmg8]

"Aftertouch (or Pressure) is a MIDI message which represents the pressure you apply to the keybed after a key has been struck and is being held down."

It clearly says here that it is AFTER the key has been struck.

This is how Channel Aftertouch has always been.

But now with Roli, saying they can apply aftertouch with the strike completely changes the behaviour.

Imagine an instrument set up to add vibrato to an already held down key using channel aftertouch. This would be fine, it would play normally and then when you want the vibrato, simply press down harder to activate it.

With the continuous aftertouch that Roli are suggesting, this same instrument would sound really bad. There would be vibrato on every single note. It wouldn't be possible to play the instrument without triggering the vibrato.

[DarkStar]

I think that ROLI is saying that the first AT message is sent with the Note On, but it has the "Strike" value. that is, Note On velocity. https://rolisupport.freshdesk.com/suppo ... 5d-touch-/. But does that mean that, for it to work "properly", AT would need to modulate whatever Note On velocity does?

What we need is someone with a ROLI keyboard to play some notes, use AT and Record all the MIDI so we can have a look.

[drewfx]

You can get channel aftertouch pretty much immediately just by playing heavy handed chords with lots of midi controllers/synths. With some HW with sensitive AT it's way too easy to get this. Is Roli implying anything new or different (other than using poly-AT)?

[EDIT: I have a Seaboard Block if I someone wants me to check something on it]

[jmg8]

You can get channel aftertouch pretty much immediately just by playing heavy handed chords with lots of midi controllers/synths. With some HW with sensitive AT it's way too easy to get this. Is Roli implying anything new or different (other than using poly-AT)?

[EDIT: I have a Seaboard Block if I someone wants me to check something on it]

From Roli:
"Most keyboards apply aftertouch to all notes equally as a single value, but the Seaboard allows you to apply aftertouch to each note individually. The Seaboard also applies aftertouch as a continuous value so that instead of starting from 0 after the initial attack of each note, it is with the Strike and at a value according to the Strike value. This means that it is also possible to fade in from silence with very gentle keywave presses."

The part that is confusing me is in the second part of the paragraph where it mentions "continuous value"
Does this mean that (assuming I have vibrato modulated by aftertouch) you would hear vibrato on every key press? Is it possible to play the instrument without triggering the vibrato?

Classic aftertouch, certainly let's you play without hearing any vibrato, only when you want to purposefully trigger it, will you hear it.

So please test on Roli for me.

[drewfx]

I'll take a look.

I should point out that people using Roli's or similar might not want vibrato on aftertouch though, as you get much more expressive vibrato just by wiggling your finger.

[jmg8]

Cool, thanks for this.

Good point about the vibrato for MPE, but for now this is just an example.

Also please test other instruments, not MSF, and please let me know which DAW you are using.
Cheers.

[drewfx]

OK. Here's what I found with my Seaboard Block.

It depends on how you implement it. Using the vibrato plugin as a per-voice effect worked OK with reasonable amounts of vibrato.

But it can be more difficult if you create a patch with something like a pitch modulated by an LFO whose depth is controlled by aftertouch. Basically on the Roli there's not a dead zone before you get aftertouch because of the way that the keys work and this can come into play with more aggressive modulation.

However, I found that by going to Globals-Show Advanced Settings-Controllers and setting Controller Smoothing-Pressure to something large like 2 o'lock or greater I get a nice delayed vibrato. So if you want to be safer you can do this as well as just limiting the depth of the modulation.

I've had mixed results with generic (non-MPE) patches using the Roli on other synths. It's really kind of a different instrument so sometimes things don't translate well to it in which case you either tweak things or move on to another patch. Velocity is tricky to control, at least for me, so I think things that disappear at low velocity is what I'm guessing is the most common problem with patches that don't work. But I haven't systematically investigated it because, you know, music.

I'm currently testing with Blue Cat's PatchWork using the VST3 MSF on Windows 10.

[Whywhy]

It's why, controllers curves are important with continuous controllers like roli.
You can setup you curves to react like you want.....
Or like a classic aftertouch keyboard :
X : 0 to 90 % : Y = 0
X : 90 to 100 % : Y : 0 to 100 linear.

[jmg8]

Thank you everyone for the help with this.