Guitar Player Question About Keyboards

[amanise]

I've tried understanding this by myself - but it's not working! So, a question would seem the only way out.

Can anyone either point me in the right direction to a good explanation - one written about reading age 6 probably - or answer if you have time please?

What is meant by the term 'aftertouch' when talking about keyboards. I see it all the time - and there are settings all over my soft synths for it - so it looks like I should know what it does/is. Is it essential?

Any advice always gratefully received!

[Sam Spoons]

AIUI aftertouch is when the key responds to additional pressure, after the initial note sounds, to modulate or change a parameter. You might use it for changing timbre or adding vibrato to a note but I believe it can be assigned to any parameter depending on the synth.

[muzines]

Hold down a note. The additional pressure you now use on the key while holding down the note is your aftertouch signal.

[Wonks]

It's a bit like playing a note on the guitar and then using the whammy bar after you've played the note, rather than simply playing the note.

As Sam says, aftertouch is just a value generated by the keyboard depending on how hard you press down on the keys. So just like any other MIDI CC (controller value) you can map it to control anything on the keyboard that can be controlled by a CC value. So it could be LFO rate to control the speed of volume modulation (for tremolo), or pitch modulation (for vibrato), or depth of chorus etc.

Depending on the keyboard it's either basic aftertouch (most common), where it's normally the value of the key pressed down the hardest that controls what happens to all the notes being played, or (on some keyboards) polyphonic aftertouch, where the pressure of each note played is converted to a signal that modifies just that note.

So if you've got a split keyboard patch with say something bassy on the bottom and brass on the top, then you can press down harder with your right hand and have the brass with vibrato whilst the bass stays steady.

Or within a chord, one single note could have vibrato or tremolo rather than it being applied to a whole chord.

[Wonks]

*You could probably do the split scenario on most keyboards with some programming, but if sometimes when using the same patch you wanted some aftertouch on the bass and sometimes not, then polyphonic AT is very useful.

[Hugh Robjohns]

Modern synth keyboards have a variety of sensors to detect how they are being played.

Originally, they just had a single contact which closed when you pressed the note, and that let through the appropriate signal (or controlled a remote switching circuit). This is known now as Note On/Off

Later, they used two contact switches, one which closed as soon as the key started to move, and a second when it reached the bottom of its travel.

The time between the two activations indicated how fast the key moved which relates to how hard it was pressed. The is Note Velocity, generally used to control note volume and/or brightness (but can be assigned for other functions too.

The next addition was Channel Aftertouch (AT), which added a pressure sensor in the keybed to detect any additional note pressure once ANY key reached the bottom of its movement. It would typically be used to introduce vibrato, or extra volume or brightness — but it affects all notes being played at the same time (hence channel), regardless of which or how many notes have extra pressure applied.

Finally, Poly-Aftertouch (P-AT) works the same way, but detects each individual note'scextea pressure (hence poly).

Consequently, while holding a chord down it's possible to highlight individual notes to make them sing above the others. Think classic Vangelis strings and brass....

It involves a more complex keyboard construction and a lot more midi data.... but it's incredibly expressive.

First introduced to synthesists in the Yamaha CS80 back in 1978...

[amanise]

I see! It all sounds amazingly clever stuff - like having a mod wheel available on every key! Which it is anyway - but like having 61 or 88 virtual mod wheels?

Thanks all - very much! I now understand. Seems it's part of the hardware end of the keyboard 'chain' rather than the MIDI channel in the DAW then? When I create a MIDI channel in my DAW, it will have sliders for various things - one of which is for aftertouch. It's just a single slider value, like the channel volume or input gain etc. I've never used it because it didn't seem to relate to anything or make any self explanatory sense. I guess, from what you all say, that I can continue to ignore it because I don't play the keyboard to record MIDI from it - but just use the piano roll editor to paint notes in and then edit their velocity etc manually if required.

[muzines]

Like the mod wheel, or most other CC values, they don't implicitly do anything other than transmit their values. It's up to the receiving instrument how it uses, or ignores that data, and what it's set up to control.

[Eddy Deegan]

I see! It all sounds amazingly clever stuff - like having a mod wheel available on every key! Which it is anyway - but like having 61 or 88 virtual mod wheels?

A keyboard with polyphonic aftertouch does indeed have something akin to a mod wheel under each key but most keyboards have channel aftertouch which can be thought of as one mod wheel shared across all the keys, and whichever key is being pressed the hardest determines the setting applied to all the notes.

There is also something between the two on the Arturia PolyBrute (and I'm sure other instruments) which is a form of duophonic aftertouch. It's like channel aftertouch but where only the last note played is modulated by key pressure. This can also be used to split the keyboard such that only one of the splits responds to aftertouch.

Although it's not aftertouch, as you mentioned mod wheels, many (most?) polyphonic synths already have a virtual mod wheel for every note played in the form of a per-voice LFO which can be used very creatively, especially if that LFO supports user-definable waveforms.

[amanise]

Very complex stuff then. Thanks all - I now understand what it does. I think I'd better leave well alone - and I don't think my MIDI controller has any capacity for it in any case now that I know what it is. It's only a very basic 90 quid one.

Thanks All!

[Wonks]

Look up its specs. You may be in luck.

[The Elf]

Aftertouch is such an expressive, visceral and organic controller it's long been a major part of my keyboard buying decisions. We are now living in times when poly aftertouch is offered on many instruments. Used well it really does transform the way a keyboard can be played, making it a much more organic instrument.

[amanise]

Look up its specs. You may be in luck.

[amanise]

Aftertouch is such an expressive, visceral and organic controller it's long been a major part of my keyboard buying decisions. We are now living in times when poly aftertouch is offered on many instruments. Used well it really does transform the way a keyboard can be played, making it a much more organic instrument.

Everything I've read about it in the context of new model keyboard evaluations is very positive about it when it's present, and now I can see why.

[N i g e l]

have you used MIDI GUITAR ? polyphonic guitar -> Midi controller ?

[amanise]

have you used MIDI GUITAR ? polyphonic guitar -> Midi controller ?

I haven't. What's all that about then? I've never really associated MIDI with stringed instruments (apart from the obvious string ensemble sample libraries etc.). I'm probably woefully behind the times.

[Kwackman]

https://www.soundonsound.com/sound-advi ... hs-podcast

Over the years Paul White has reviewed just about every guitar/midi/synth ever produced. Worth searching here and maybe the excellent Muzines site for reviews.

[N i g e l]

there's a VST - Midi Guitar 2. Guitar 1/4" signal in to PC, MIDI out

https://www.jamorigin.com/

lots of demos on uTube of course but I think you can down load it and try it out with some limitations.

This guy says MIDI Guitar 3 is just about to go to beta and mentions stuff like MPE, chicken/egg, controller/synthesizer, technique, tracking, phrasing....

25mins, theres more playing from 22min+

https://www.youtube.com/watch?v=QeO_MzrrLY0

[amanise]

Smashing! More stuff to get into. Thanks again all!

[BigRedX]

I've tried nearly all the pitch detection guitar systems and while they have got better over the last 45 years all of them still require you to make significant changes to your playing technique to get the best out of them and then there is always the problem with increasing latency on the lower notes.

In a way I was lucky in that when I was initially interested in these systems they were too expensive and unreliable compared with a decent keyboard synth, so I chose to develop some rudimentary keyboard technique instead. I keep coming back to "guitar synths" and I continue to be disappointed. And now Roland appear to have abandoned their modelling and wave-shaping technology (V-System) in favour of returning to pitch detection.

As someone who plays both guitar and keyboards (albeit badly) I find each brings different ideas to my songwriting, and sometimes the best ideas are when I transfer something I came up with on the guitar to the keyboard and vice-versa, when something extra happens in the translation.

[Wonks]

I keep coming back to "guitar synths" and I continue to be disappointed. And now Roland appear to have abandoned their modelling and wave-shaping technology (V-System) in favour of returning to pitch detection.

I’m not sure that’s really true. Since 2007’7 VG99, there’s modelling and wave-shaping technology in the SY300 (2015), the SY1 (2019), the SY1000 (2020) and SY200 (2022). Just because 2023’s SY800 and associated GK5 pickup are using pitch to MIDI doesn’t mean the modelling/wave shaping side has been abandoned.

And whilst the SY800 doesn’t make any big improvements on the pitch/MIDI latency side of things, its accuracy and responsiveness make it so much more playable than the older GR units, at least on guitar. For bass, it will still be better than before but it will have noticeable lag that the modelling doesn’t have.

Modelling/wave shaping technology can do a lot of things but it can only do so much. Pitch to MIDI offers all the sounds that the modelling and wave shaping can’t do. Not everyone wants a limited range of analogue synth sounds, (as lovely as they are).

I’d expect to see a new modelling module out that utilises the GK5’s digital connection. The SY800 has a GK5 link output, and whilst it could simply power another SY800, I’d think it likely we’ll see a compatible modelling module fairly soon.

Guitar synthesis is a pretty limited market (and bass guitar synthesis even more so) so I can’t see Rolland/Boss bringing out a new product in this area more than once every 1-2 years.

But Japanese synth companies and their offerings are a law unto themselves, so anything could happen.

[amanise]

...
As someone who plays both guitar and keyboards (albeit badly) I find each brings different ideas to my songwriting, and sometimes the best ideas are when I transfer something I came up with on the guitar to the keyboard and vice-versa, when something extra happens in the translation.

Yes - can completely relate to that experience. The two work so differently they can end up having a real input to the process in their own rights. I rather like the difference. As I said, making things up on a keyboard gets me out of all my bad guitar habits. It always seemed to me that things like guitar, violin, cello etc. would all be very hard to synthesise and get right. But that was a long time ago - so probably no longer applies.

[BigRedX]

While wave-shaping and modelling might be limited, pitch detection alone will never be able to beat the laws of physics, which for me is a far more serious limitation. So far the only way around it for fretted instruments is to use fret sensing, but unfortunately the best known version of this system appears to be having significant logistical and financial difficulties.

I'll wait for a replacement for the SY1000 that uses the new pickup and re-evaluate. In the mean time my synths sounds will be played from either a keyboard or a computer.

[Wonks]

I had a YouRock MIDI guitar that should have got round the pitch to MIDI issues, but to play, it was just as laggy as my GK2a Strat into my GR20 (which actually isn't that bad if you avoid the low notes).

I got it after YouRock were no more and the editing software was unavailable, which might have helped (after I got rid of it, somebody then made the editing software available - typical!).

I know Arkieboy uses an SY1000 and GM800 (I kept incorrectly using SY800 in my post above ) as his live rig, with the GKC-AD converting his GK3 signal to digital for the GM800 and he's very happy with it.

But certainly, no lag at all would be fantastic.

[sonics]

Since this is (now) about MIDI guitars, has anyone tried a Jamstik?