Moog Music Forum

I recently got a Matriarch and wanted to try incorporationg aftertouch into a patch.
However, I found out that I need to apply a lot of pressure to the keys before the KB AT OUT voltage starts increasing, and then it increases to its maximum fairly quickly (I double-checked the voltage with an oscilloscope).

To give you an idea of the required pressure, compared to keyboard velocity: if play hard staccato notes so that the keyboard velocity is more than maxed out, the AT voltage does not move, or at most wiggle below 100 mV.

I've never had any instrument with aftertouch before, so I don't know if that's just how it's supposed to be.
However, I would usually never press this hard on a keyboard, and I'm kind of afraid of breaking something. Might there be something wrong with my unit, or is this just how it is?

I am currently comparing the aftertouch on my Matriarch and Model-D. My Matriarch seems to work reasonably well, in my opinion. It is hard, of course, to gauge what you mean by a “lot of pressure”. My suggestion, for comparison on these keyboards is this: Press firmly near the end of a white key while touching the far-end of the same key with another finger. As you press down, there is a point where your pressing finger feels the key “click” a little bit — and — the back of the key lifts up a couple of millimeters. The aftertouch voltage should reach maximum a little before this pressure. On the other hand, the aftertouch voltage should initially start with fairly low force. And you should be able to (roughly) hold the voltage at intermediate voltages. It is not easy be smooth with the force, at first.

Do understand, however, that aftertouch applies to pressure of sustained notes. It is not really practical to generate aftertouch data when playing staccato notes. In fact, the aftertouch circuit uses a fairly slow smoothing filter, so even if the sensor was briefly spiked by a sharp hit, this would be filtered out before it reached the AT output.

Thanks for your reply!
It didn’t know about the AT voltage being filtered/smoothed out.

I tried your suggestion, and the aftertouch does indeed max out shortly before the key clicks. So apparently at least the maximum is where it‘s supposed to be (and I‘m not pressing too hard ).

I still find the minimum required pressure kind of strong and wouldn’t call it fairly low, but I suppose that is very subjective and my Matrairch is probably fine. Holding an intermediate voltage isn’t easy, but doable with some practice I think.

Glad it seems to be working for you.