Understanding AMS (foot pedal vs knobs)

[thenewandy]

Hello there,

It depends what you want to achieve. I thought you only wanted to replace the Knob 6 with your pedal for the program.

My end goal is to understand how this thing works. That I couldn't replace the knob with the pedal was a pretty good sign that I didn't understand it.

Right now, I get why I can't replace them, but I don't understand why I can't get the strings to go silent when I turn off AMS but directly modify the "Velocity Intensity" value myself.

Velocity intensity is one thing, and the other AMS are others. They don't have to be working together at all. In other words, if you like the effect that the strings get louder when you play harder, then keep the current velocity intensity midway at +63. And as you know, if you want the strings to stay the same loudness regardless of velocity, use 0 for this setting.

Ah - I was thinking these were AMS things for the velocity intensity itself, not the velocity.

Of course, your chosen Velocity intensity value will influence the Amp Level on the Amp tab. Same with the chosen values for the other AMS settings. But again, you decide how you want the strings to behave. So if you use 0 for velocity, you might need to turn the Amp Level down before adjusting the pedal AMS level, etc. And use the AMS mixers if needed to create exponential reaction for a single source like your pedal, etc. Hope this helps !

Ok - I think I am nearly there with getting it.

I can get the foot pedal to behave like the knob (in non-[+] mode) by running it through an AMS mixer, and putting it in "offset" mode. With that (offset=-100, amount=199) then it seems to behave like the knob.

Now, the only bit I don't get is why I can't get the same result if I:
1) Set the Amp level to 0
2) Set he Amp Mod AMS to be Knob 6 [+] with intensity of +99.

I would have expected that with this, I could use the knob to go from silent to audible, but if I do this, I only get silence, regardless of where the knob is. I could explain this if the AMS was multiplicative (i.e. it was multiplying the amp level by some amount, but since the amp level was 0, it was always 0) but if that were the case, then I would have expected that just using the [+] version of the knob would have been able to get silence in the first place.

[KK]

I can get the foot pedal to behave like the knob (in non-[+] mode) by running it through an AMS mixer, and putting it in "offset" mode. With that (offset=-100, amount=199) then it seems to behave like the knob.

Hey, that's a great find, even more effective !

[thenewandy]

I can get the foot pedal to behave like the knob (in non-[+] mode) by running it through an AMS mixer, and putting it in "offset" mode. With that (offset=-100, amount=199) then it seems to behave like the knob.

Hey, that's a great find, even more effective !

Yes, but I still don't understand why I need to do the "offseting" in the AMS, rather than just changing the Amp Level to 0.

[KK]

Yes, but I still don't understand why I need to do the "offsetting" in the AMS, rather than just changing the Amp Level to 0.

Simply because as you discovered, mod multiplies the Amp output. So you need to have a non-zero value for Amp Level (since 0 times anything stays 0). See Converting from unipolar to bipolar in the PG, page 104. That's exactly what happens here (I was mentioning unidirectional/bidirectional instead, earlier in this thread).

So in this case you gave your "unidirectional" source/device (pedal) a "bidirectional" action, exactly as the Kronos knob #6 with center position initially "at 0". I'll definitely remember this - great forum here and as you discovered, trying out things often create solutions and interesting results. Thanks so much !

[thenewandy]

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[thenewandy]

Yes, but I still don't understand why I need to do the "offsetting" in the AMS, rather than just changing the Amp Level to 0.

Simply because as you discovered, mod multiplies the Amp output. So you need to have a non-zero value for Amp Level (since 0 times anything stays 0). See Converting from unipolar to bipolar in the PG, page 104. That's exactly what happens here (I was mentioning unidirectional/bidirectional instead, earlier in this thread).

This isn't what I am seeing though. With the knob in [+] mode, you would expect that putting it to the minimum value would mean that the AMS value is 0, hence it should be possible to silence the strings.

And if the combination is multiplicative, then a bipolar AMS makes no sense - because the thing that is being modulated (amp level) is always positive. So, if the AMS can go negative (i.e. it is bipolar) and the AMS is multiplied by the Amp Level, then you would expect that as soon as the AMS is outputting negative values, the Amp Level would be multiplied by a negative number, which makes it negative, which then would lead to it clipping to 0 and being silent. If this were the case, then all the negative region of the AMS would sound the same (with the strings being silent).

This isn't to say that I'm convinced that it is additive either - if it were additive, then setting the amp level to 0 would not mean that output is always silent.

It seems like it is something like

Used = AmpLevel * ((100 + AMS) / 200)

But I don't see where this offset of 100 is documented or anything (the 200 isn't really documented, but without some scaling like this, then multiplicative AMS wouldn't work at all)

[KK]

With the knob in [+] mode, you would expect that putting it to the minimum value would mean that the AMS value is 0, hence it should be possible to silence the strings.

A modulation value of 0 simply means it does nothing (no change) on the Amp Level, so for this reason it can not silence it.

It seems like it is something like

Used = AmpLevel * (100 + AMS)

But I don't see where this 100 is documented or anything.

Here is written another way (sorry, English is not my native language) :

Amp level is one separate thing and as long as it is not 0, regardless if you set it at 100 or 50 etc, the AMS will make it vary as much as the Amp Mod intensity you define. If Amp Mod Intensity is set to 99, to silence the Amp Level whatever it is, you will need -99 at your AMS. If Amp Mod intensity is at 50, then you authorize the AMS to modify the Amp level only half way, so to silence it you now need to have twice as much as the usual max of 99 %, so using for example an AMS Mixer with A and B at -99 (that is what I meant earlier by multiplicative).

Again, the problem in this particular program is the knob 6 mode, put in a "bidirectional" kind of way, with the preset value at center position. Since your pedal can only behave in an unidirectional way, it can not silence the strings at its minimum value (foot up at the beginning of its course), because the knob 6 minimum value when totally counterclockwise represents -99 and not 0 (even though the MIDI value seen at the output would be 00 in hex just like your pedal).

So by offsetting the mid-way value using the AMS Mixer in Offset mode, you solve the problem. The -100 offset makes your pedal in the "foot up" position silence the sound as with the knob totally counterclockwise and all works correctly.

[DavidPicard]

Hi Thenewwandy,

I've been looking everywhere for an answer to this question.
I'm having exactly the same issue as you are...

I would like to be able to modulate different parameters (positively and negatively) with the foot pedal.
Kind of what I used to do on the Nord Stage...

I figured the only way is with global set to cc#04 and through the AMS but I get the same result.

Did you find a solution to this issue ?

[KingKronos]

The foot pedal cc4 goes from 0 to 127.

So any parameter that also goes from 0 to some max amount can be assigned normally to the foot pedal.

But for those kinds of parameters that go from negative to 0 to positive, an extra step must be considered. The default will probably be at 0, so you should instead set it to max negative.

So with no input from the pedal (pedal up), the parameter will be max negative. As you depress the pedal to halfway, the parameter value will reach 0. Likewise, as you continue to press the pedal, the parameter value will increase until you reach max positive (pedal fully down).