Where's aftertouch on most keyboards? Don't you guys use it?

[AnX]

I'm really puzzled about that Vince Clark vid. Does he really not know what aftertouch is, or is he having a laugh about the Arturia guys, who taught him aftertouch? I mean, i can't really magine that someone who has seen centuries of snythesizers, and has a whole shitload of them in his studio, doesn't know about aftertouch. On the other hand, some musicians (no offense) clouded their minds so hard with drugs, that i wouldn't be surprised if he actually doesn't know about aftertouch.

He's taking the piss.... and im pretty sure his mind isnt clouded by drugs ( he never said yes when i offered them)

Doubt he ever uses it tho, he hardly holds a note down long enough

[aMUSEd]

( he never said yes when i offered them)

Unlike John Martyn

[chk071]

So what would be an example of a keyboard with good aftertouch? I can only say from my M-Audio Axiom 2nd gen, that i wouldn't even think about making extensive use of aftertouch on that, because the application of a precise value via aftertouch is simply not possible. Gotta press the key really hard to apply aftertouch, and when you do so, you obviously have very small control over the actual value you're applying.

[BBFG#]

Many guitar players can't handle light gauge strings either. Should string manufacturers only make heavy gauge to 'help' everyone play stable and consistent? And equally have guitar makers take off those whammy bars?
Of course not,

IMO, any keyboard over 1K USD should have velocity, release velocity and poly-after touch. And I personally would like a four-way joystick, second modwheel, and x/y strip for added keyboard triggers. And let's throw two x-y squares to implement those special synth functions (ala alchemy/zebra) on top of that. Move forward not backwards.

In regards to common place routing these days, I've notice many software samples/patch/programs have the mod wheel set to timbre/volume. So after-touch would be nice to add the vibrato (or tremolo), as well as other nuances. It could also be set for the half tone up while the mod wheel is set for the 6 semi tone (one mimicking the finger bend while the other mimicking the 'whammy-bar'). Often the aftertouch brings in another sound, or depth in reverb/delay effects or putting the 'swell' in the sound of backing orchestrations. In short, the performance techniques are only limited by a lack of imagination of what to do with them. The fact that others want that limitation imposed on all is a bit procrustean.

[chk071]

The fact that others want that limitation imposed on all is a bit procrustean.

I don't think anyone really wants that. But, i think it's valid to ask who really uses aftertouch. Actually, i bought my MIDI keyboard partly because it has aftertouch. I hardly ever make use of it in the end though. Much prefer mod and pitch bend wheel. For the rest, i also have knobs and sliders.

[Jace-BeOS]

I've written on this topic before....it's an unfortunate state of affairs to be honest: Aftertouch....However, by aftertouch you really mean channel aftertouch. This (channel, mono-aftertouch) ought to be relegated to the pages of history and every keyboard released ought to have polyphonic-aftertouch. We have velocity, which is independent for each key, so we should have pressure sensitivity available on per-key basis. Pressure is one of the most natural musical gestures: press-in* on the surface you play to obtain an expressive gesture, and yet the keyboard technology is absolutely dumb here.

* press-in, which can be translated as 'sliding' on some harder surfaces, it also applies to breath controlled instruments, or bowed instruments, any continuous modulation controller. And whereas when playing a reed instrument we can only obtain a mono-breath response, naturally, with electronic keyboards we can play chords, so it is natural to want independed pressure for each key in a chord.

It's sad that even expensive synths do not have bog-standard channel-pressure (I won't mention names!).

Fully agreed.

Out of 9 keyboards with MIDI, I have only two controllers that offer aftertouch. Both are 88-key Alesis synthesizers (Fusion 8HD and QS8). Neither of those have poly aftertouch (channel only). It annoys me that almost nothing has poly aftertouch, and only slightly more controllers even have channel aftertouch.

At this point, if the Roli Seaboard wasn't so well known for its problems, I'd be saving money for a Seaboard (which is near impossible for me to do, as the smallest seaboard is way outside my price range, but I REALLY want a more expressive playing surface).

[BBFG#]

The fact that others want that limitation imposed on all is a bit procrustean.

I don't think anyone really wants that. But, i think it's valid to ask who really uses aftertouch. Actually, i bought my MIDI keyboard partly because it has aftertouch. I hardly ever make use of it in the end though. Much prefer mod and pitch bend wheel. For the rest, i also have knobs and sliders.

Fair enough, but then we come back to that guitarists analogy. Because the majority of guitar players don't use light gauge (or in my case, custom gauge) string packs or whammy bars (I think the majority use medium gauge with no bar. At least that was the average when I was managing music stores).

Being that I'm most often playing between four keyboards in my set up, having these options are more than just a luxury. And in the case of my spouse on her keyboard, she finds the wheels non-intuitive and prefers after touch far over any knob or wheel.

[Rappo Clappo]

I use 0.09. With the springs of my strat adjusted as loose as possible. I don't bend or use the whammy. The chords sound very nice and clean.

I don't use the aftertouch because I want to spare my keyboard.

[aciddose]

That is a valid point. Unfortunately, many aftertouch mechanisms are not tuned well. Most behave almost as an on-off switch, difficult to control and balance. We press in, there is nothing...and...suddenly there is everything!

It doesn't have to be that way. It's a matter of good design. There are keyboards with good pressure response. Just recently I spent all day with the new Minimoog Model D, which amazingly, has aftertouch! It's one of the best aftertouch designs I've played! So smooth, playable, responsive...However, I don't know if it's due to the CV control or not...Maybe someone who knows can clarify,

It's a very simple issue actually. The response will always be non-linear, exponential actually. So you need a log(x), which is quite simply a diode in the feedback path of an opamp.

Other than that, you have the offset/bias/threshold which is sort of the "start point" of the value. Beyond the threshold/bias pressure the value starts to change. This is a value which is added/subtracted to the sensor input.

Last you have the scale/gain of the signal. Beyond the threshold pressure, how much pressure needs to be applied to get the maximum output value?

So the equation is something like:

aftertouch = gain * log(signal - threshold)

The circuit is extremely simple, you need a buffer opamp to measure the sensor to begin with and you can add/scale the resulting buffered signal to apply the threshold. From there you need another opamp with a diode in the feedback path, you can also have a trim here to adjust the gain at the same time.

A slightly better circuit might allow you to carefully adjust the compensation to ensure the value is as linear as desired. This would be one more gain parameter inside the log function.

As it turns out many if not all keyboards with aftertouch have these adjustments on the circuit board. Over time, corrosion or dirt built up on the sensors makes them less sensitive and the threshold/gains need to be adjusted to compensate. Cleaning the sensors can also help a lot.

For example the alpha-junos and a few other keyboards with a left/right bender bar rather than a wheel use a pressure sensor behind the bender. This can be adjusted in the same way to make it far more easy to use rather than on/off.

[JCJR]

Many guitar players can't handle light gauge strings either. Should string manufacturers only make heavy gauge to 'help' everyone play stable and consistent? And equally have guitar makers take off those whammy bars?
... The fact that others want that limitation imposed on all is a bit procrustean.

Well part of the thread title is "Don't you guys use it?"

I usually don't care one way or t'other whether a keyboard has channel or poly AT. If it has AT then it should be defeatable, and there should be a parameter to tell the KB to send either channel or poly AT, whichever is desired. And the KB ought to have software settings to adjust the aftertouch sensitivity, threshold, etc.

I play a lot of piano and organ and keybass. None need AT though keybass could benefit from AT if it tracks good enough that the bass line can be played with low risk of accidental AT.

I used to use a lot more mod/pitch wheel long ago. Will still use it on occasion, but came to "artistic judgement" that any except rare playtime mod on synth or orchestral parts is tasteless and tacky. The keyboard player trying to be something he ain't.

A possible engineering aspect of adding AT to a keyboard-- If the sensing technology senses position, the keys (for poly AT) or the entire keybed (channel AT) need to move beyond the normal bottoming of the key. A sensitive easy to invoke AT might need quite a bit of extra motion on the bottom of the stroke, and be fairly loose-sprung so you don't have to work hard to invoke it. Or alternately make the extra motion stiff and shallow, resulting in AT you have to work hard to use.

Just saying, a loose spring loaded AT mechanism might have nice aftertouch feel but also result in a spongy-feeling keyboard that might feel rather weird for piano, clav, hammond playing styles. Those go down and hit the bottom "hard" and might feel weird with extra give past the normal bottom position.

Modern precision electronic scales use strain gages that are "stiff". The scale platform often visually doesn't look like it moves according to the weight. The platform looks like it goes down about the same amount regardless whether you load it with a gram or a kg. So maybe using a real stiff strain gage as used in electronic scales, you could build a keyboard with a "hard bottom" like grand piano or Hammond action, but still responds appropriately to extra pressure?

I have an acculab gram-resolution scale that is accurate to the gram up to a max of 10 kg. That is 10000 steps of good repeatable resolution, and the platform moves a max of 1 mm or less under load. A strain gage like that wedged under a keyboard frame for channel AT might allow a firm bottom to the key feel while also allowing very good software adjustment of threshold and sensitivity?

Maybe some key mechanisms work that way, dunno.

[aciddose]

Pressure sensors do not pick up position, they pick up pressure. I think any other implementation would be prohibitively expensive and too fragile or finicky to be used in a keybed.

The existing analog circuits can be controlled digitally by replacing the resistors with DACs or "digital resistors". The only issue is that there wouldn't be much to gain from this. Once you have good precision and linearity, you can convert from one skew to any other skew in software without much loss. For example you might convert 12 bits and only end up with 7. This allows you to lose up to 5 bits when applying the skew.

Aftertouch is called aftertouch because of the implementation. In MIDI (where the name in common use comes from) it is a message that is only sent after note-on. This is due to the fact it is implemented (I've never seen anything else) with pressure sensors while velocity is based upon a time interval. Therefore you always get note -> velocity -> pressure in that order as by the time the pressure threshold has been met, the velocity has already been input.

Poly pressure is called this because it is polyphonic aftertouch. Since aftertouch could be called pressure, it makes more sense to apply the term to polyphonic pressure and simply call it "pressure" for short.

Aftertouch and pressure are also nice and short (10, 8 characters) and don't take up a lot of space on a display. So the naming convention is based upon an assortment of convenient choices.

[jdnz]

Pressure sensors do not pick up position, they pick up pressure. I think any other implementation would be prohibitively expensive and too fragile or finicky to be used in a keybed.

I reckon the purely optical sensor setup used on the vaxmidi is the way to go - no pressure sensors, no switches/contact pads, it's elegant and means you can have aftertouch that is finely modulatable (my pet peeve of pressure transducer setups)

http://vaxmidi.com/

other option is wait for someone to do a properly integrated keyboard with touch sensitive tops (ala the ill fated endeavour controller ) - if you can treat the top of each key as an x/y controller there should be no need for aftertouch

[ghettosynth]

Pressure sensors do not pick up position, they pick up pressure. I think any other implementation would be prohibitively expensive and too fragile or finicky to be used in a keybed.

I reckon the purely optical sensor setup used on the vaxmidi is the way to go - no pressure sensors, no switches/contact pads, it's elegant and means you can have aftertouch that is finely modulatable (my pet peeve of pressure transducer setups)

http://vaxmidi.com/

other option is wait for someone to do a properly integrated keyboard with touch sensitive tops (ala the ill fated endeavour controller ) - if you can treat the top of each key as an x/y controller there should be no need for aftertouch

Only if the software is well implemented to interpret area as pressure.

I'm kind of on a quest now. I want poly pressure as well as attack and release velocity. The only value of x/y position, per se, on the keytop for me is as a source of pseudo-randomness.

The design of the mechanics though is really important. The only controller that I have, AFAIK, with aftertouch is my Ozonic keyboard. While I don't hate it, I don't love it either. it is squishy at the bottom. I want a definite piano like bottom with smooth pressure response thereafter.

For me, this is the issue with most controllers, there just expensive, not actually high quality.

[jdnz]

The design of the mechanics though is really important. The only controller that I have, AFAIK, with aftertouch is my Ozonic keyboard. While I don't hate it, I don't love it either. it is squishy at the bottom. I want a definite piano like bottom with smooth pressure response thereafter.

I gave up and got a roland rd64 - same weighted hammer action as the a88 controller and like the a88 you can use the d-beam for aftertouch, took a bit of getting used to but works well (much better a/t modulation than my old novation where aftertouch was almost binary)

[AnX]

( he never said yes when i offered them)

Unlike John Martyn

That is one crazy dude