RME and pitch bend stepping artifacts

Funkasizer · Post by **Funkasizer** » Mon Jun 04, 2007 3:29 am

Hi everybody,

I am the proud new owner of a Voyager RME, and I am loving it, except for the fact that there is very clear stepping when using the pitch bend wheel on my MIDI controller keyboard. Someone suggested that my MIDI controller might have insufficient resolution, but it is working fine with my DSI PolyEvolver Rack. Any help would be much appreciated!

Cheers,

Jack

goldphinga · Post by **goldphinga** » Mon Jun 04, 2007 4:15 am

isnt there a parameter where you can change the resolution of the midi input on the rme? im sure theres one on the voyager....

Funkasizer · Post by **Funkasizer** » Mon Jun 04, 2007 6:02 am

Thanks for the tip, Goldphinga. I thought the MIDI resolution setting was only for MIDI sends, but I will try it as soon as I am back home.

Funkasizer · Post by **Funkasizer** » Mon Jun 04, 2007 2:35 pm

Unfortunately, the Voyager RME has no mod wheel resolution setting. Any further suggestions? Thanks in advance,

Jack

RL · Post by RL » Mon Jun 04, 2007 2:49 pm

How is the setting of the pitch wheel amount (+/- 1 Octave or more)?
The Voyager receives 14 bit pitch wheel resolution and you can't change it in a menu. I guess your master keyboard only sends 7 bits.
Rudi

Funkasizer · Post by **Funkasizer** » Tue Jun 05, 2007 4:30 pm

The pitch wheel amount is usually set to +/- 1 octave or less. I checked the pitch bend midi messages sent from my master keyboard (CME UF7) with Midipipe, and it appears to be 14 bit. Any further suggestions?

RL · Post by RL » Tue Jun 05, 2007 6:15 pm

Is the software version 3.3 in your RME?

Funkasizer · Post by **Funkasizer** » Wed Jun 06, 2007 3:42 am

Yes, it is a brand new RME with software version 3.3

Funkasizer · Post by **Funkasizer** » Sat Jun 09, 2007 9:04 am

Found myself a relatively cheap store demo of a Fatar-Studiologic SL-760, and no more stepping artifacts in the pitch bend!! Too bad for the investment I made in my CME UF7...

Cheers,

Jack

Gonga · Post by **Gonga** » Tue Jul 03, 2007 9:05 pm

I have precisely the same problem with my Novation x-station, which is my midi controller

Someone on that forum says the x-station is 7-bit.

Can anyone recommend a midi controller or synth that's compatible and has aftertouch and a joystick for pitch? Korg? Roland?

Is it fixable with a patch RL? It would be a really useful option to be able to switch to 7-bit for pitch and mod.

Funkasizer · Post by **Funkasizer** » Wed Jul 04, 2007 5:42 am

The new Edirol series of midi controllers has aftertouch and a joystick for mod and pitch bend. I tried one in a store but did not like the keys: they are a bit shorter than "regular" keys, and this gives a weird sensation when depressing them.

I don't think the stepping artifact is related to the resolution of the pitch bend wheel. My CME UF7 was 14 bit (checked it with a Midi message spy tool) and I doubt that the X-station would be only 7-bit. In my case it was not so much the resolution that gave the problem, but the low number of midi pitch bend messages sent out by the controller.

Gonga · Post by **Gonga** » Wed Jul 04, 2007 4:26 pm

Thanks Funkasizer. I'll look into the Edirols. The PCR-800 has aftertouch. The keys do look like normal size, so they must be pretty close.

I didn't know pitch bend message rates varied among controllers. Midi can be such a pain! I wonder if there's a way to adjust this on my x-station.

Gonga · Post by **Gonga** » Thu Jul 05, 2007 6:10 am

Novation contacted me - their tech support is very responsive.

The tech said the x-station is 14-bit, but that pitch bend has a resolution of only 128 steps, so that when you bend large intervals, you will hear stepping.

So if this is true, then why is it that some controllers don't make the Voyager produce stepping artifacts? Or will all controllers produce stepping if the bend range is wide enough?

I'd like to be able to set the bend for a whammy-bar style pitch drop of an octave or more.

Maybe midi isn't capable of this. Does anybody use a voltage controller for pitch?

till · Post by **till** » Thu Jul 05, 2007 8:27 am

Gonga wrote:...
I didn't know pitch bend message rates varied among controllers.
...

Technically , they do not vary the bit depth at all. The just don't use the full range of 2 by the power of 14 = 16384 different values.
They set the least significant bits of the two 7 bit words to a static value.
this way they can use less quality pots in the pitchbend and/or cheaper A/D converters to get the analog voltage of the pot measured and transformed into a digital value.

If a company uses average parts, it should be no problem to get better then 7 bit resolution for the pitchbend.
14 bit needs some well chosen electronics and sometimes a little software routine to smooth and/or "cleaning" the data stream.

If you have a 14 bit pitchbend assigned to a range of an octave, you have 16384/2 possible steps for this octave. This should give you 8192/1200 = about 6,8 steps per cent tuning. And this is not bad at all. Some synths with DCOs and some softsynths are using a frequency resolution that is not as good as this.

So blame the manufacture of the pitchbend sending device.

And talking about quality:
A good quality cost a bit more.
Just like Moog Voyager is not cheap. But it is worth every cent !

synthetic · Post by **synthetic** » Thu Jul 05, 2007 8:55 am

Funk, make sure the CME is only sending MIDI on one channel. It may be set to send on channels 1-4 simultaneously, for example. If that's the case, then you might get bogged down when sending a bunch of MIDI data like pitch bend of mod. My Studiologic defaults to zones 1-4 on and I have to turn off 2, 3, 4 to keep from overloading stuff. (Could be the controller, MIDI interface, synth or combination of the three.)