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rich.o

Volume Jumping w/ Expression Pedals

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Problem: PX-560 | CC doesn't provide smooth volume control when pedal is assigned to CC11:Expression

 

I bought the M-Audio EX-P expression pedal. Calibrated and assigned it to CC 11 controller so I could control volume with my foot. I returned it back because it seemed to be causing a very noticeable volume jump just as the layer fades in. I was expecting the expression pedal to increase the volume smoothly, just like when you use the keyboard's master volume knob, but that's not what happened. Initially, the sound jumps from off to some low level; and it's definitely a jump and nothing like a fade in. As I further depress the pedal, it's not smooth at all in the first ~25-33% of travel. Once I'm past that first third of the travel, the pedal seems to operate smoothly. But it really kills anything subtle you're trying to do at lower volume levels. 

 

So I bought the Moog ACCEP003 EP3 expression pedal. Plugged it in; calibrated it, and same thing - volume jumping at initial fade-in and then along the first 25 - 33% of travel. Kind of like a detented pot, if you know what I mean by that. It's looking like my PX-560 is the problem. Now it could be just my keyboard, but I'm thinking that people just haven't noticed it yet because they're fading in a sound while another sound is already playing so the problem would be masked. That other sound could be coming from their own keyboard or their band mates' instruments. Either way, it probably wouldn't be noticeable. Took a while before I caught it.

 

Anyway, I'm assuming this problem exists for all PX-560's. I'm guessing it's a firmware issue where the code/function that interprets and translates the pedal's variable resistance/impedance at its lowest levels is not granular enough to produce a smooth continuous controller response over the entire range of travel on the pedal. Maybe it's a problem having to do with the characteristics of the pedal's potentiometer, but I'm betting that routine could be written that notices when jump in db is about to happen and branch off to a subroutine that smooths out that volume level transition over time. You'd have to have to play with the timing so that is sounds natural/believable/reponsive, or as close to it as possible, but I bet could be done. 

 

Thoughts?

 

Thanks!

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I'm having the same problem. It's pretty frustrating to purchase a "flagship" model and have it not work properly on something as basic as a smooth volume transition with an expression pedal.  I've tried it with THREE different pedals - all display the same behavior.  Moreover, I've tested each of these pedals on 3 other keyboards (each one) and the ALL work perfectly.  This is clearly a problem with the 560 and it should be fixed immediately.

 

The other thing I have a big issue with is not being able to select a "registration" with a simple midi message.  I mean, really? What's up with that? I can do it with the XW-P1, but not with the 560. 

 

 

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For what it's worth, my experience with expression pedals: I already had a Yamaha FC7, and I could plug it in and calibrate it and it would sort-of work but no matter how I fiddled with parameters I could never get it to smoothly sweep across the range I wanted to.

 

So I bought a Roland EV-5, because it was one of the ones listed as tested on p. EN-10 of the manual.  It's been fine for my purposes.  But my ear or my requirements may be different from yours.  I was testing with filter cutoff on an analog synth sound, and expression on an organ sound.  In both cases I'd be unlikely to notice imperfect behavior near zero.  For example in the organ case I care about making the organ more or less prominent compared to the rest of the band, I'm probably never going to need it to fade in or out smoothly from silence.

 

OK, I tried it just now: I set the EV-5 to control volume of a string sound, turned master volume all the way up and used the internal speakers, and: yeah, it's unpredictable and jumpy at the bottom of the range.  Bah.

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Exactly what I have been seeing. This is a recode for Casio. Gotta manage those subtle volume increases without jumping. Pretty much kills the thought of recording anything with CC:11 set to expression.

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I 'd like to buy an expression pedal that definitely works properly with my PX-560.

From what I've read here, there is a problem.

 

I have an Korg expression pedal which works well on my Korg keyboard, but only the first 25% of travel works on the PX-560.

No doubt this is something to do with the potentiometer impedance.

 

Are any senior forum contributors, who own a PX-560, aware of this issue ?

And is Casio looking at the problem ?

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Hello

I have Moog EP-3 and it works perfectly. Did you try with different positions of switches. At the bottom and on side; my positions to those  are like this:

1481027065428.jpg

1481026998382.jpg

AlenK likes this

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Here's an update to the thread and another confirmation of the problem. I recently purchased two expression pedals: the Roland EV-5 and the Moog EP-3. The first is on Casio's list of verified pedals. The second is not but it actually cost less than the EV-5 and, well, it's from Moog! I always wanted something from Moog and this is about all I could afford from them (:)) so after Mark's informative post above I took a small chance and bought it too. I'm glad I did. Although the EV-5 and EP-3 are both made primarily of plastic (with metal base plates) the EP-3 is much heavier, seemingly much more solid (thicker plastic?) and a little smoother in operation. It's taller but that isn't usually a downside for a foot-pedal.

 

I can confirm the basics of Mark's post above. With the bottom switch in the "Other" position and the trim knob on the side of the pedal in the position shown, the pedal worked as well as the EV-5 when the latter was used with its trim knob in the "0" position (any other position just adds resistance in series with the pedal's main potentiometer, which serves to change the minimum voltage output from the pedal). But, that is not to say it worked _perfectly_. With either pedal I heard the problem people are reporting above. I heard it regardless of whether I recalibrated when switching pedals or not (I actually didn't really have to recalibrate - each pedal worked more-or-less the same with the other's calibration settings).

 

I listened very carefully and this is what I heard: When moving from minimum value (heel down) to maximum value (toe down) the volume when adjusting CC#11 (Expression) abruptly jumped from zero to not-zero at a particular (clockwise) rotation point, then jumped to _another_ slightly louder level with a couple of degrees further rotation and then, usually, smoothly increased from there to maximum. ("Usually" because I sometimes heard a _third_ abrupt step a few more degrees of rotation after I heard the second step.)  When going in the other direction, from toe fully down to heel fully down, I heard an abrupt lowering of volume at some point in the (anticlockwise) rotation from toe fully down and then a smooth reduction in volume until near the bottom of travel, when I usually heard an abrupt step back to zero volume. However, sometimes I did _not_ hear the abrupt step and the volume merely decreased to a very low value that was _not_ zero.

 

So, inconsistent behavior dependent on position (angle), direction of rotation, and, perhaps, random chance but none of it correct. BOTH pedals exhibited the problem, the difference being that in the case of the EP-3 the first abrupt transition from zero volume to low volume during clockwise rotation from full heel down, and from low volume to zero volume during anti-clockwise rotation, occurred much closer to the bottom of the pedal's travel (almost near the end, in fact). I suspect this has something to do with the two pedals having different effective linearity's for some reason. This may be why Mark reported perfect operation; it happens so close to the end of travel that it is very easy to miss.

 

The fact that the EP-3 works at all strongly suggests to me that the PX-560 (and probably the MZ-X models as well) does not necessarily require a pedal with a 10Kohm potentiometer despite what the user's guide indicates (the MZ-X manuals seem to be missing that information!). MOST expression pedals work as simple voltage dividers, using the potentiometer to send some fraction of a reference voltage sent by the keyboard back to it. The full resistance value of the pot is thus immaterial to this function; it only affects the amount of current that the pedal's full resistance draws and the current sent back to the ADC inside the keyboard that is reading the divided voltage. 

 

If the full resistance value is too low the current drawn from the voltage reference output may be more than the source of that voltage (ultimately a pin on a chip inside the keyboard) should or can provide. So you probably shouldn't go much lower than the 10K "requirement," otherwise you could stress the chip or even cause chip failure (if the circuit designer did not adequately protect against that possibility). If, OTOH, the full resistance is too high the ADC may not be able to measure the divided voltage properly. However, in the latter case the resistance would have to be very high indeed. I measured resistances between 25K and a bit over 100K when rotating the EP-3 pedal and those evidently do not cause any problem with reading the voltage. (At least with my PX-560 and EP-3: YMMV.)

 

The PX-560 (and MZ-X models) appear to connect the reference voltage to the ring and the divided voltage to the tip, with the sleeve connected to ground. The verified pedals listed in the PX-560 user's guide appear to operate that way. (Note that the Kurzweil CC-1 is actually a re-branded Fatar.) I believe, but have not verified, that the EP-3's "polarity" switch swaps the ring with the tip. I will have to do further investigation of that. IIRC, I did not get correct operation with the switch in the "standard" position.

 

Upshot is, there is indeed a significant "bug" with the way the PX-560 reads the expression pedal. I don't know if this was fixed in the MZ-X models or whether it is fixable with a mere software update in the case of the PX-560. I hope so. Depending on exactly how you are using the expression pedal the bug may or may not affect your playing. Regardless, it is undeniably there and deserves to be addressed by Casio in the next firmware update if it is possible to do so.

PriviaMan likes this

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14 hours ago, AlenK said:

Here's an update to the thread and another confirmation of the problem. I recently purchased two expression pedals: the Roland EV-5 and the Moog EP-3. The first is on Casio's list of verified pedals. The second is not but it actually cost less than the EV-5 and, well, it's from Moog! I always wanted something from Moog and this is about all I could afford from them (:)) so after Mark's informative post above I took a small chance and bought it too. I'm glad I did. Although the EV-5 and EP-3 are both made primarily of plastic (with metal base plates) the EP-3 is much heavier, seemingly much more solid (thicker plastic?) and a little smoother in operation. It's taller but that isn't usually a downside for a foot-pedal.

 

I can confirm the basics of Mark's post above. With the bottom switch in the "Other" position and the trim knob on the side of the pedal in the position shown, the pedal worked as well as the EV-5 when the latter was used with its trim knob in the "0" position (any other position just adds resistance in series with the pedal's main potentiometer, which serves to change the minimum voltage output from the pedal). But, that is not to say it worked _perfectly_. With either pedal I heard the problem people are reporting above. I heard it regardless of whether I recalibrated when switching pedals or not (I actually didn't really have to recalibrate - each pedal worked more-or-less the same with the other's calibration settings).

 

I listened very carefully and this is what I heard: When moving from minimum value (heel down) to maximum value (toe down) the volume when adjusting CC#11 (Expression) abruptly jumped from zero to not-zero at a particular (clockwise) rotation point, then jumped to _another_ slightly louder level with a couple of degrees further rotation and then, usually, smoothly increased from there to maximum. ("Usually" because I sometimes heard a _third_ abrupt step a few more degrees of rotation after I heard the second step.)  When going in the other direction, from toe fully down to heel fully down, I heard an abrupt lowering of volume at some point in the (anticlockwise) rotation from toe fully down and then a smooth reduction in volume until near the bottom of travel, when I usually heard an abrupt step back to zero volume. However, sometimes I did _not_ hear the abrupt step and the volume merely decreased to a very low value that was _not_ zero.

 

So, inconsistent behavior dependent on position (angle), direction of rotation, and, perhaps, random chance but none of it correct. BOTH pedals exhibited the problem, the difference being that in the case of the EP-3 the first abrupt transition from zero volume to low volume during clockwise rotation from full heel down, and from low volume to zero volume during anti-clockwise rotation, occurred much closer to the bottom of the pedal's travel (almost near the end, in fact). I suspect this has something to do with the two pedals having different effective linearity's for some reason. This may be why Mark reported perfect operation; it happens so close to the end of travel that it is very easy to miss.

 

The fact that the EP-3 works at all strongly suggests to me that the PX-560 (and probably the MZ-X models as well) does not necessarily require a pedal with a 10Kohm potentiometer despite what the user's guide indicates (the MZ-X manuals seem to be missing that information!). MOST expression pedals work as simple voltage dividers, using the potentiometer to send some fraction of a reference voltage sent by the keyboard back to it. The full resistance value of the pot is thus immaterial to this function; it only affects the amount of current that the pedal's full resistance draws and the current sent back to the ADC inside the keyboard that is reading the divided voltage. 

 

If the full resistance value is too low the current drawn from the voltage reference output may be more than the source of that voltage (ultimately a pin on a chip inside the keyboard) should or can provide. So you probably shouldn't go much lower than the 10K "requirement," otherwise you could stress the chip or even cause chip failure (if the circuit designer did not adequately protect against that possibility). If, OTOH, the full resistance is too high the ADC may not be able to measure the divided voltage properly. However, in the latter case the resistance would have to be very high indeed. I measured resistances between 25K and a bit over 100K when rotating the EP-3 pedal and those evidently do not cause any problem with reading the voltage. (At least with my PX-560 and EP-3: YMMV.)

 

The PX-560 (and MZ-X models) appear to connect the reference voltage to the ring and the divided voltage to the tip, with the sleeve connected to ground. The verified pedals listed in the PX-560 user's guide appear to operate that way. (Note that the Kurzweil CC-1 is actually a re-branded Fatar.) I believe, but have not verified, that the EP-3's "polarity" switch swaps the ring with the tip. I will have to do further investigation of that. IIRC, I did not get correct operation with the switch in the "standard" position.

 

Upshot is, there is indeed a significant "bug" with the way the PX-560 reads the expression pedal. I don't know if this was fixed in the MZ-X models or whether it is fixable with a mere software update in the case of the PX-560. I hope so. Depending on exactly how you are using the expression pedal the bug may or may not affect your playing. Regardless, it is undeniably there and deserves to be addressed by Casio in the next firmware update if it is possible to do so.

 

 

Agree 100% it should be looked at by Casio and hopefully be fixed with firmware update.

Casio support please pay attention to this bug. Thanks.

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