Expression Pedal for Solaris

[niversen]

I have Mission Engineering EP-1 plugged into the Expression Pedal input and can't get it to change anything. This is a 10k "low impedance" expression pedal. I have a TRS cable connecting it to the Solaris.

It is my understanding that the Solaris takes this input and routes it to "Expression"/Volume, which is exactly what I want - volume. It does not appear that the expression pedal input is listed in the modulation list (unless it is also known as "Pedal1 or Pedal 2".

Can anyone clarify? Do I need a high-impedance pedal for use with the Solaris?

Thanks,

Nathanael

[John Bowen]

Well....you have to program the Expression pedal (otherwise known as Pedal 1 in the Home pages) to control the volume.

Because of an earlier hardware problem back in 2011, I had to go through all factory presets at the time and reprogram them to not have the Expression set to Volume. I still have the original presets of mine that DO have it programmed, so I can send these to you to save some time, however, there's quite a few banks since then that have been added, and I don't think any of these have it programmed.

What I should have done is put a Global option as one of the assignments, and just defaulted all of the presets to that, so one could go in and easily set both pedals to something - hope to change that in the next OS!!

-john

[niversen]

John, I did the Home page setup. On pg 2/4, I set the "ExpPed" parameter to " Expr". Changing the polarity has no effect. I also went to VCA1 and set Pedal 1 to modulate the VCA by 100%, figuring that might also be necessary. This has had no effect on the sound. Am I missing something obvious, like I have the wrong impedance pot in the pedal? I think 10K is a pretty standard value for keyboard expression inputs, but maybe I'm wrong.

I can easily modify the presets that are most useful to me and then just change the INIT patch for stuff I'm working on, though I do agree that putting this into the Global INIT in the way you suggested makes a lot of sense.

Nathanael

[niversen]

I can confirm that a sustain pedal works fine in the Sustain pedal jack. I turn SusPed1 to "Sustain", set polarity to "-" and I am in business. I notice that there is a SusPedal2 in the menu, but no jack for that on the back. It is currently "Off" in my sample patch.

[niversen]

I believe this pedal defaults to "tip-to-wiper" for contacts. I've tried it fully inserted and also pulled out to the first "notch" to disconnect the tip. I can measure 4+ V at the end of the TRS cable coming from the Solaris with the positive terminal of the meter on the tip and the negative on either the ring or the wiper, so it appears that the Solaris is sending out normal signals for an expression jack (same as my main controller keyboard, anyway).

[niversen]

OK, I have this sorted. The key information is that the measurement is taken between the ring and sleeve. Inside my pedal, I reversed the tip and ring wires, and everything worked as soon as I enabled the Expression pedal in the Home menu.

One thing I noticed is that there is some scratchiness as I move the expression pedal. Also, the expression pedal does not affect the digital output. This leads me to believe that the expression pedal, like the volume knob is an analog circuit and only affects the analog outs (headphone included). I will run the expression pedal into an extra input on my controller keyboard and just run it back to the Solaris via MIDI as a CC. If I run this through Mainstage, I can even then adjust the response curve on the way back to the Solaris.

Technology.... always a way to get it done, and many things to learn along the way. Then, once it is set up and working, one hardly ever thinks about it again.

[John Bowen]

Really sorry you had to do so much investigation for this! I unfortunately do not have an Expression pedal; I use a simple external volume pedal (stereo) when I need to control it for demos. A MIDI volume pedal control should work as well.

john b.

[niversen]

Yes, that does it. Expression pedal >>controller keyboard>>Mainstage. The controller keyboard inverts the MIDI numbers for CC11 (127==0; 0==127). Mainstage applies a mapping curve, then passes that into the Solaris as CC1. Send Solaris CC1 to a Lag Processor. Route Lag processor to VCA modulation set at -100%. Now the volume is off when on its "heel" and full when on the "toe". Desired behavior achieved across all outputs, but there is a slight zipper artifact at the "off" end of the pedal travel.

[niversen]

John, If I use Mainstage to transform CC11 to CC7 (MIDI Volume), there is no change in output on the Solaris through any of its outputs. I'm sure I could map it like CC11, but I can save a transform and just use CC11. I'm not sure that a MIDI volume pedal will do anything without CC mapping in the Solaris.

Also, by way of completeness, I can't seem use the Expression Pedal input as a modulation source. If I plug my pedal in for expression, and then set the mod source to "Pedal1", there is no change in output if I modulate the VCA by -100%. Sutain1 definitely works for a Sustain Pedal. I'm not sure why Sustain2 is in the UI, since there isn't a second jack, but maybe the EXPR input doubles? Not sure.

For me, I will stick with MIDI CC11 if I need to control the Solaris directly. I will likely also explore using the pedal to control my RME interface's digital mixer and just attenuate there, or even run the audio up to Mainstage to attenuate on a channel strip (a few extra ms of latency aren't going to be noticed). Even with the lag processor set at 500ms, I can't get the zippering to go away on CC11. It is more pronounced at the "heel" or "off" end of the pedal travel, and inaudible near the maximum "on". Easy to hear with headphones/in-ears if exposed. Impossible in a busy mix. Would be audible on an exposed fade-in from nothing. It does not occur on fade-out, thankfully.

I suppose the best answer would be interpolation code for all the CC inputs so that they are automatically smoothed internally. I can't think of why I'd want a CC controller to jump or zipper. The softsynths I use must interpolate because they don't exhibit this zippering artifact.

I can also just get a stereo volume pedal and do this in the analog domain. It just seemed to make sense to run digital into the RME's mixer and then submix there with stuff coming from Mainstage and pass 2ch to FOH.

[John Bowen]

Odd...I know that MIDI Volume (CC7) works, because I've used it many times. Make sure you have Volume in the MIDI page (lower right parameter) turned On.

[John Bowen]

The reason Julian put in 2 Sustain Pedals for switch sources (SusPed1 and SusPed2) is because he had a double sustain pedal unit that worked with the Solaris when it was plugged into the Sus Pedal jack (a single stereo jack). I haven't been able to find that pedal on the market, and I don't remember what model it was.

What is confusing is that in the Modulation Source list, Ped1 is the Expression Pedal jack, and Ped2 is the Sustain pedal jack. Are you quite sure you don't get anything using Ped1 as the Source, and then use your Expression pedal? I like to route it to pitch to more readily hear and verify that things are working (I tried this with the Sustain pedal, and it only affected the pitch when the Source was set to Ped2).

[niversen]

John,

I think I know why the zippering is occurring for me on CC11 - it is my controller map. I wanted a curve that was much flatter for much of the travel and then tapered significantly at the "zero" end of the pedal (a modified exponential curve - flatter at one end than the other. This makes it so there is more room for expression in medium-high values than in low ones. This also reduces the effective resolution in what is sent to the Solaris at the low extreme. This is why a lag processor doesn't work. The gaps are just too big with an 8-bit representation if the curve is steep at the low end. This is also why the zippering goes away at higher values - there is plenty of resolution there.

I don't experience this on my soft synths because they are clearly interpolating the data at a higher bit depth to get the intermediate points. The Solaris does not interpolate CC data, and so, the zippering is evident when the effective resolution drops.

The feature request would be to have the Solaris automatically smooth CC data to higher resolution internally. Since it seems most internal parameters use NRPN to get higher resolution, perhaps it would be possible to smooth the data as the CC is converted to internal NRPN representation. (Making an asusmption here that may not be true.) I can't think of why I'd want CC's to jump, but maybe someone likes that - the world is a big place.

As it is, I will just run the audio up into Mainstage and control it there. It interpolates and fades smoothly, and the goal is to blend the Solaris into my rig anyway. A extra ms or two of latency is of no concern - just the time to run in the RME as a digital signal, up to Mainstage and then out the A/D. So, I know how to get what I want (a volume pedal for the Solaris that is smooth and continuous). I could do this in the analog domain as well, I'd just need a non-scratchy pot in the pedal.

Hopefully all this is helpful to someone in the future. I think I understand it now, and that is a good thing.

[John Bowen]

I appreciate the research and posting here...it definitely will help others!

[niversen]

To close the loop:

1) The Expression/Pedal1 input definitely serves as a modulation source. I set it to modulate LinFM and Pitch successfully. A standard 10k Ohm expression pedal works fine. The expression pedal should be wired "reversed" - that is with the ring and wiper being the in/out of the pot, and the tip going to ground. Turn it to "EXPR" in the Home menu, polarity to "+" and then assign it to a Mod source or Lag processor as desired.

2) I have static noise at the low extremity of the range when modulating/controlling volume. I cannot tell if it is due to being in the audio path, or if it is due to "zipper noise" on the digital side. If the swell is fast, it is not audible. A gradual fade, and there is a "scritch" as the pedal starts to move. The lag processor is ineffective in removing or changing this - even at 500ms. This may be an indication that it is a "scratchy pot" if analog signal is going through the pedal. I do not know how it is wired internally, and haven't opened it. My curiosity is not that great.

3) The expression pedal does not change the volume coming out of the SPDIF output. It does adjust the headphones, and presumably outputs 1&2, though I didn't check them explicitly. It does what one expects: from "0" to "full" on what seems to be a linear slope.

3) If I instead run the pedal into Mainstage via my master keyboard, it registers 0-127 as expected, and anything in Mainstage is smooth and zipper-free, regardless of curve for the data. I presume this is because the software I use is all interpolating the data into smooth curves at increased internal resolution.

4) If I run the pedal through Mainstage and then back to the Bowen as CC11 (expression), and map this to one of the CC1-5's, I can get smooth control as long as I don't use a logarithmic type of curve. Linear response is smooth and glitch-free. The logarithmic curve fares poorly because the Solaris does not seem to be interpolating the 8-bit (0-127) MIDI data into a larger bit depth internally, though I do not know that concretely, just my external deduction. The lag processor does not help this issue, presumably because the jumps are just too large to smooth without real interpolation. Obviously, if I was using the pedal for something other than volume, and without my personal preference for a curve involved, it works exactly as expected.

5) My personal preference is to not care as much about fine control for the last 25% of volume, and I'd prefer a curve that lets me use that pedal travel in a more useful range of volumes. I will implement my volume control of the Solaris in Mainstage as an audio signal. 100% repeatable, I get my cake and to eat it too, and the Solaris pumps out luscious, gorgeous sound as always.

This whole exercise has been for me more about sorting out what is 100% repeatable, dependable, and the best solution for me than any real complaint about the product. I think it would be great for the Solaris to interpolate internally, but if it never does, I'm still thrilled with the purchase and moving forward. With Pitch/Mod/Joystick/Ribbon and all the knobs it isn't like I'm lacking for ways to alter the sound. With a floor-based volume control working in my rig as a whole, I'm in business.

[John Bowen]

Yes, I should make it clear that Expression or Volume control will not affect the S/P-DIF. We would have had to attach another converter to the system just to do that, and there was some other issues that I can't recall.