Expression Pedal Weirdness... advice? (Not polarity/range)

[enigma0Z]

Hi all...

 

I'm trying to figure out what's going on with my M-Audio M-EXP. I have it hooked up to my Axiom 49, and as I sweep the pedal, at random times, it jumps up to the full 127 value, and then back down to wherever the pedal is actually at. I could live with it if I were just recording MIDI data by deleting the offending points, but I also use this keyboard to play live, and unless I'm going for a glitchy effect, this pretty much kills the use of the expression pedal.

 

I'm thinking the pedal has just gone south, but is there anything that I could do to diagnose the issue better?

 

Thanks...

[Delaware Dave]

If you have access to a different exp pedal you should try to see if it also does it with that one. If you don't you have one then take your keyboard to your local music store and try one in the store with your keyboard. If it works then you know for sure it is your pedal and not the keyboard intermittently reading the MIDI data incorrectly.

[David R]

It could either be the pedal or the Axiom itself. My old Axiom 61 started sending mod wheel messages without me touching it. They're known to be glitchy...

[JeffLearman]

Might be a dirty pot. try some contact cleaner spray on the pot. Also might be one of the conductors or connector leads failing. Make sure the plug is well-seated in the jack.

 

I'm having a small issue that when I bring my pedal full up (lowest volume), if I push against the stop at all, it goes to 127. So, I gotta be careful when I'm trying to be quiet. Kinda ruins a fade-out to blast at full volume at the end!

 

Fortunately it's still easy to avoid. I think I'll get a new pedal and keep this one in the kit as a backup.

[enigma0Z]

All, thanks for the tips. I'll be trying them out later this week (don't have any time until Thursday or Friday). If anyone else has a tip, please feel free to share it.

 

@delaware dave - I have another MIDI device I can pop the pedal into to get an idea of what's the cause. That should work, in theory, yes?

 

@dave R - Glitchy, really? For what it's worth, this is the verison 2 of the Axiom series, but I haven't had any glitchy issues with it. At least not yet, *fingers crossed*

 

@learjeff - Honestly it behaves like I'd expect a dirty pot. The cable is definitely seated and clicked in, but I can try jiggling it around to see if it reproduces the error more frequently/easier. The pots aren't sealed, so I should be able to us contact cleaner on them, but should I take the pots out of the plastic housing of the pedal first?

[Jaime Chimuelo]

It's ca;libration, the Axiom has gone south. the 0-128 is what you are getting wich isn;t very accurate, but M audio has a buffer tha acts as a cure to smooth out the sefault state to target, and it sounds like that has gone south or been disabled accidentally.

[enigma0Z]

It's ca;libration, the Axiom has gone south. the 0-128 is what you are getting wich isn;t very accurate, but M audio has a buffer tha acts as a cure to smooth out the sefault state to target, and it sounds like that has gone south or been disabled accidentally.

 

I'm not 100% sure what you mean here. Is there a page or document that I can find that will maybe explain it further?

 

The sweep isn't the issue, I get an appropriate value at any point in the sweep of the pedal, but it will randomly blip up to 127 (max) as I move it. It's not wavy or constantly changing, or even reporting inaccurately other than the blips. If I record a smooth sweep, it records a smooth sweep except for a blip or two. If I hold it steady, it holds steady except (once again) for a blip or two.

[JeffLearman]

Don't take the pot out, just open it up and give it a good squirt, then work the pedal a lot.

 

Perhaps Jaime is referring to debouncing/filtering, which the software can (I'd say, should) do automatically. But there's a limit to what software can do in this regard; if it goes overboard then you can't slam the pedal down fast and have the sound respond. No idea whether it's configurable on the Axiom; I haven't seen that on the two keyboards I have that take pedals.

 

Note that DAW software wouldn't filter, so you can see the bad data points clearly in that case. Any filtering that should be happening would be at the control input before it gets converted to MIDI. Once it's MIDI we wouldn't want any filtering to happen, or else we couldn't record a MIDI track with a step and have the sound module respond instantly.

[David R]

@dave R - Glitchy, really? For what it's worth, this is the verison 2 of the Axiom series, but I haven't had any glitchy issues with it. At least not yet, *fingers crossed*

Yeah, I went through two Axiom mk1s, and at the end of their lives, what really rendered them nearly unusable was that my modulation wheel was sending CC messages all the time, regardless of whether I touched it or not. They're also supremely susceptible to static - the slightest discharge when you plug the USB cable in, and knobs and buttons go out of order. I've had friends whose mk1 wouldn't boot up the morning after a gig; and there's the dead note issue that M-Audio is aware of but seemingly refuses to fix.

 

Anyway, my mk2 is behaving itself for the moment, but I'm also treating it with kid gloves. I love the layout of the Axioms and they give me everything I need for my gigs, but they're very temperamental. The build quality on the mk2 is significantly better.

 

It could be an issue with the pedal itself, though. Check the jack and the cable. Sometimes the pot on the side gets rotated in transit, or the switch on the bottom to select "M-Audio" or "Other"

[nmcq]

NO NO hold on; This sounds like the "jump" experienced when changing patches in software instruments (but also some hardware instruments) no? Are you playing software instruments, like VB3 or such? Wait, it's a controller, so of course you are. Assuming so, it's a common behavior when you switch from one patch where the pedal (and volume or expression in the software) are at a high setting, to a new patch which has expression or volume at a low setting, and then touch the pedal even lightly, or go to move it. The software is still playing at that low level, and it can't tell what level the hardware pedal is at until it physically moves, at which time the software expression/volume "jumps" to match the hardware level.

 

It can be a real drag on stage, especially when the sound man rushes up and throttles you live after you blast his eardrums out after a patch change. Fortunately, keyboard players have been saved by merely changing the behavior, in the software, to "pickup", or "relative" software.

 

It can be complex, if this is the situation post that it's so and I can write some more on ways to deal with it. If not, I wasted many valuable finger motions that could have been playing scales :-). (P.S. I know the difference between expression and volume, just using both here because not sure what kind of instrument being played).

 

Neil

[JeffLearman]

Note that he says "at random times."

[nmcq]

Note that he says "at random times."

 

Yea, saw that, but he may not realize that what seems like "random times" is actually tied to a movement of the expression pedal. Even resting my foot on it moves mine. I was just wanting to rule this out as a cause, because it sure sounds like what happens to me if I don't watch my software versus hardware parameter positions on output or expression levels after a patch change. I hate using "pickup" settings, but I hate a sudden jump to "10" at a gig when it's set to "jump" worse.... I could be off base, just checking it.

 

Neil

[enigma0Z]

@All - something I forgot to note, plus, some updates (see the end of the post for the rest of the updates). First of all, what I forgot to note is this is all MIDI over USB, individual USB devices plugged into a hub. There are, in my current rig, three bus-powered USB MIDI devices, a foot controller (Logidy UMI3), a control surface (Korg NanoKontrol), and the Axiom. There's an additional keyboard, but it's externally powered, and there is a USB key used to activate my software, Reason, to enable me to use it. The USB hub is not powered, although it can be, I don't use the PSU because the cord is very short.

 

Second, the update. I plugged my exp pedal into the Logidy controler, and as I type, I am sweeping it back and forth without symptom, so I think we can dismiss the pedal as the problem.

 

@ learjeff - Regarding Jaime, if it's a debouncing issue (which I do understand), that would explain it, but I currently don't want to believe that my $300 controller has gone bad. There is no such configuration on the Axiom to disable or tweak this.

 

@ nmcq - No, it's not a patch change issue as you describe. I spent a good deal of time figuring ways to work around that, but in the end the endless encoders on the Axiom are what sold me.

 

Regarding the USB nature of my setup, is it possible that if the Axiom were underpowered, that it would respond dodgy like this with the exp pedal? The reason I ask is because there have been a few instances where the "demo mode" warning light went off on Reason indicating that it couldn't see the ignition key (the little USB key). I suspect that it is because the key lost power. Additionally, I have noticed several times where the LCD on my Axiom was uncharacteristically dim. Not the backlight, but the LCD letters/numbers weren't as dark and clear as they should have been. Combine that with the (now obvious) fact that the pedal isn't bad, I'm wondering if it's just a simple power issue.

 

For what it's worth, I tried jiggling the cable to get a reaction, but didn't get one. I have now tested the pedal in a different controller and verified the pedal works. I think the next logical step would be to plug the Axiom in direct to the USB on my mac and see if that helps, yes?

 

I'll report back with my findings. In the meantime, if you get other ideas, please post 'em.

 

Thanks.

 

[JeffLearman]

If the Axiom is USB-powered, then low USB power could cause lots of problems. What's it plugged into now, if not directly into your Mac?

[enigma0Z]

It's plugged into an unpowered USB hub with a number of other devices, both powered and unpowered. The unpowered devices are the Reason ignition key, a Logidy foot controller, a Korg NanoKontrol, and of course the Axiom. That all goes into the mac along with a Casio PX-130, but the PX-130 is powered externally.

[ITGITC]

For what it's worth, I tried jiggling the cable to get a reaction, but didn't get one.

 

Same here. I even tried watching racy movies... no reaction.

 

Getting old's a bitch.

 

My guess is that the USB hub, being unpowered, is causing your problems.

 

Tom

 

[nmcq]

... but in the end the endless encoders on the Axiom are what sold me.

 

Why did the endless encoders sell you? What are they doing for you that's different than non-endless-encoders?

 

I have a Novation 61SL MkII and am pretty sure I'm not utilizing the endless encoders for all they're worth.

 

thanks

 

Neil

[enigma0Z]

The endless encoders don't reset when you change patches. That's basically it. Of course, little did I realize, but the Axiom has a "mute" function that causes the hardware faders to not send ctrl sequences until their value matches that of the DAW. Oh well. I jump around patches a bit mid-song and mid-set... having a value jump up to hi-energy when I'm supposed to be playing something chill is bad... and so is the reverse. I almost got the Novation, but between that and the M-Audio, I didn't like that the Novation had that intermediary software to interface with the DAW, plus I like the M-Audio's drum pads more.

 

Also, another update (I think it's the pedal for more sure now, hopefully, maybe) ... So, I got the keyboard home again and did some more playing. I think I've determine the following:

 

1) My little foot controller with the exp in (that I used to test it) probably is better at debouncing than the Axiom.

 

2) It's not a power or USB-related issue

 

3) The foot pedal pot (not the minimum value adjustment pot) is bad

 

So, here's what I did... I brought it home and plugged the Axiom directly into my mac. Swept the pedal up and down and it's as fuzzy as ever. It doesn't matter how fast or slow I go--it happens either way. In fact, if I go slow it's more likely to be apparent because the fast movement isn't masking it. Following this, I then grabbed the pedal, kept it in the toe up position, and swept the adjustment pot on the side up and down. Lo and behold, no jumps.

 

I would assume that if there were a problem with the keyboard, it would have shown up no matter which pot was turning, the foot pedal pot or the adjustment pot, yes? I would aso assume that it it were a power issue, plugging directly into the computer would have "fixed" the issue, yes?

 

Assuming that I'm not the only one that thinks my logic is sound, I think I'll be getting a Boss FV-something to replace the cheap plastic M-Audio I currently use. And possibly move it over to the little foot controller, since it seems to like that one.

[enigma0Z]

(and it rises from the dead!!)

 

Just wanted to post one more update for anyone who cares... I bought a Yamaha FC7 and reversed the polarity on it using some audio cable trickery... works flawlessly. Therefore... at least currently it appears as if... the M-Audio EX-P is the problem. I'm doing an RMA on it at the moment.