PreSonus Faderport 2 - stuttery rotary encoder

Greetings Friends,
I’m using the PreSonus Faderport 2 unit with the nightly builds. Works great. Yet, there is one exception to that. And the is the performance of the one rotary encoder it has.

From using it to scroll the timeline, or thru the channels, to using it for panning, everything I use it for has a stutter to it, going one direction, then the other way, and back again, then maybe WAY the other way, etc. If this was an old unit, I would also have to suspect the physical control itself. I’ve seen plenty of encoders to this on many digital consoles (Yamaha, Digico). But, my unit is brand new.

How do I find out which side of the fence the problem lies, in Ardour or the device? In other words, how can I see the data performance as I rotate the control?

PS. the unit is on the latest firmware.

Thank you for help,


Maybe a midi monitor should do that job :wink:

I don’t think it’s Ardour as I haven’t encountered that problem with my Faderport 2 (I’m using the Mac version of Ardour 6 beta). The scroll wheel has been working fine. I do occasionally notice a flicker with it when scrolling the timeline. But no artifacts with panning for example.

As @Sahaathyva suggested a MIDI monitor that shows events sent by the device.

In Ardour you can use Menu > Window > MIDI Tracer
Then select the Faderports as Source.

Turning the encoder sends MIDI Control Change Messages (0xB0):

  • The Pan / Param Encoder: 0xB0, 0x10, xx
  • Session Navigator Encoder: 0xB0, 0x3C, xx

where xx is delta value bit (Bit 6 = direction, Bits 0-5 = number of steps.
You should see values xx > 64 (0x40) for clock-wise and < 64 for anti-clockwise movements).

PS. Preferably first disable the control surface so that you can test it standalone.

Hi. Thank you for that suggestion. I’ll look into that.

Interesting… I’m glad yours is working well. I bet I got a bad unit.

Thank you for this data. This will help so much.

Hi Robin,
So, I downloaded kMidiMon and took a look at the ouput of my Faderport2 unit.

I did indeed see what you mentioned regarding expected data for the rotary encoder.
And, as I thought, I could see it jump around. I did two caputures: 1 while continually turning the control clockwise. 2. then another going anti-clockwise. Here are the results:

So, I guess its time to contact ProSonus and get a replacement unit.

PS. its interesting that there are different values withing each direction. Would you know why that is? Why not have one value for each direction? Hmmmmm.

Thank you so much for all your help!

Robin answered that above:

Emphasis added. So in short most of the variation in values in each direction is a result of the Presonus reporting how fast it is being turned as well. The faster it is turned, the more ‘steps’. What can be tricky about this is reading it from a standpoint of a non-programmer, you have to remember that all numbers in a computer are binary, so when they refer to bits they are referring the the individual places of the binary number you are seeing the equivalent to in either the Hex (In Robin’s post) or the Decimal (In your screenshots).

What is odd about your screenshot are the occasional blips in the wrong direction (Assuming you were constantly moving it in the direction you described) and the occasional outlier values that would be difficult if not impossible for you to speed up and slow down your direction that much that quick I would expect. That being said I would be curious to see what that trace looks like for someone else on different hardware.


Just like OP stated, I’ve also seen rotary knobs misbehave just like this in microwave ovens, mixers, headphone monitor boxes. It seems most rotary knobs develop these symptoms after 1 - 3 years of usage. It’s probably due to oxidation because spraying deoxidation fluid restores normal operation for a couple of months and then the symptoms return. Maybe this unit has been on the self of the seller for a while ?

In the first screen-capture 127 is huge outlier. That is a huge skip forward in he middle of moderate movement. The occasional “snap back” (1) is fine. That can happen with a knob that clicks in to place.

The counter-clockwise movement also looks back. There is a lot of forth and back, and more than just a single step clockswise. This cannot be explained by a detent.

I have a Faderport-8 and that produces a much cleaner signal, and no outliers.

I don’t know if this is common with the 2nd generator Faderport, but if there is still warranty on the device, I’d return it.

As mentioned above, I’m not experiencing it with my 2nd generation Faderport. The only strangeness I see when using the encoder to scroll (which to be honest I never do in practice because the scroll wheel of my mouse is more efficient) is an occasional flash of the playhead in which it jumps backward for a split-second when scrolling forward and then returns; I also see this occasionally when scrolling backward – in that case the playhead jumps forward for a split second and then returns. But this behavior doesn’t show up when panning (which is a good use for the encoder dial).

Thank you everyone for chiming in and helping me with this! We all know now that the issue is withing my unit. And thank you for explaining the various values. Speed of turn makes sense.

I have sent this same data to PreSonus for their review. Hopefully, we can work something out.

Thank you so much,

This is usually due to the grease that lubricates the shaft having liquefied and dripped onto the circuit board preventing the brushes to make contact. This can be fixed on most encoders by disasembling them and clean up the mess.Oxidation spray might help in some cases by diluting that grease a bit, but it doesn’t remove it so the fix is very temporary.

1 Like

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.