Exp pedal margin?

E.S.

Member
In Setup->Utilities->ADC Levels there is a Percent value for each expression pedal. For example, my FV-50 goes from 0% to 99%.
After calibrating the pedal and using it as Source for a Modifier, I noticed something unexpected. It is not until this Percent value goes higher than 5% that the yellow ball starts moving in the Modifier view in FM3-Edit. Similarly, the yellow ball reaches the top of the modifier already at 95%.
So it would seem that the calibration procedure reserves 5% both at the top and the bottom, thereby limiting the effective range of the pedal.
My other exp pedal is an EV-30, which suffers from the same issue, but with slightly different Percent values.

It is very cool that the FM3 provides this kind of technical detail. But I can't help wondering what the reason is for this 2 x 5% margin?
Wouldn't it be better to let the modifier react to the full "electrical" range of the pedal?
 
The calibration "scales" the range provided by the pedal to 100%.

A "perfect" expression pedal would offer a range of 0-127. In my experience they typically go from 0 to about 115 or so.

The calibration adjusts the available range of your pedal so that it your pedals min-max is 100%.

Sounds like you might have an offset on the modifier settings. Post a screen shot.
 
It is very cool that the FM3 provides this kind of technical detail. But I can't help wondering what the reason is for this 2 x 5% margin?
Wouldn't it be better to let the modifier react to the full "electrical" range of the pedal?
many pedals physically move but don’t send any “electrical” signal in those margins. People say boss pedals are notorious for this.
 
It sounds like E.S. is saying the ADC values change but no modifier dot movement occurs in the highest & lowest 5% or so of the value range that would have been seen during calibration.

If this actually occurs, it's probably to ensure a steady min/max value when something doesn't return to the calibrated value perfectly every time. For example, calibrating and pressing down on rubber stoppers a bit while the actual resting position isn't quite that far up/down.

I can see how this might be annoying sometimes. The Axe-FX II doesn't seem to do that, and it's nice to have the response to the full pedal travel, or be able to set smaller safety zones like 1% via modifier scale.
 
It sounds like E.S. is saying the ADC values change but no modifier dot movement occurs in the highest & lowest 5% or so of the value range that would have been seen during calibration.

If this actually occurs, it's probably to ensure a steady min/max value when something doesn't return to the calibrated value perfectly every time. For example, calibrating and pressing down on rubber stoppers a bit while the actual resting position isn't quite that far up/down.
That's exactly what I was trying to say - thanks for helping me explain it! :)
I understand why a certain 'margin' would be useful for the reasons you mention.

I can see how this might be annoying sometimes. The Axe-FX II doesn't seem to do that, and it's nice to have the response to the full pedal travel, or be able to set smaller safety zones like 1% via modifier scale.

Here are some quick measurements of the effective pedal travel, with and without these 5% safety zones. I'm simply measuring the gap between the min and max positions, at the top of the pedal.

FV-50H:
23 mm - electrical/ADC range
16 mm - effective modifier range

EV-30:
28 mm - electrical/ADC range
19 mm - effective modifier range

Note that the mechanical margins that @chris refers to are excluded in both figures.

The FV-50 is certainly not the best expression pedal available (though it's light and robust). But given the choice I would be very tempted to reduce those safety margins, thereby increasing the effective range of the pedals. I believe it would be quite noticeable.
 
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