I have been using the cutoff knob for sweeps, but I just set up my bcf2000. I have been using it for menu parameters but not with parameters on the front panel. I thought the long throw faders would be ideal for filter sweeps. I also had the idea of setting multiple faders to cutoff in order to tap different cutoff values while performing a sweep to glitch it out. That worked out pretty well.
In addition, I set one fader up in 7-bit to compare to 14-bit setting. I want to record the sweeps on my sequencer (command station) and I wanted to hear if doubling the bit rate was worth the extra data to store and sent. To my surprise there was very little improvement from 7-bit to 14-bit with a high resonance. The zippering was about as 1/2 as noticable not 1/127 as noticable.
Does anyone else send fast 14-bit midi cutoff sweeps and still notice zippering? If you do then I know it's not my controller. Is it the Phatty's ability to handle incoming midi? I have an LP stage 1 OS 3.1.
14-bit zipper just as bad as 7-bit (Filter sweep)
Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
The easiest way to tackle these MIDI problems, is to use a MIDI monitor to actually see the MIDI data being sent and recieved. So many factors involved and vary from different manufactures.
Using a MIDI monitor to look at 14-bit slider/wheel/knob data reveals what is actually happening. For instance I can move a 14-bit MIDI slider from zero to max as fast as I can, and only get about 20 MIDI messages, ranging from 0,MSB-0,LSB to 127,MSB-127,LSB. It all depends on the scan rate and how the manufacturer decided to implement handling MIDI data. The question changes from why do I get stepping/zippering, to how can it not step/zipper. Simple answer is that, it IS what it IS, digital equals steps, no matter how fine you make them. If you are going from 0 volts to 5 volts in only 20 steps, you are going to hear the steps. Change the range from 0 to 1 volt and those 20 steps are much smoother.
My experience with Moog's handling of 14-bit data, would seem the resolution is 0-255 steps or double that of a standard 0-127 step MIDI CC used on most MIDI synthesizers. But not 128 times the resolution. Would be too much MIDI data for that on any system, no? My best guess it that Moog is handling the LSB like a switch where 0-63 is one value and 64-127 is the next value. So for the Moog filter cut-off that has a range of 0-255 would be something like:
Filter amount 0 = 0,MSB 0-63,LSB
Filter amount 1 = 0,MSB 64-127,LSB
Filter amount 2 = 1,MSB 0-63,LSB
Filter amount 3 = 1,MSB 64-127,LSB
And so on.
At least these are the results I have been getting, still better than only 128 steps. But like you said "The zippering was about as 1/2 as noticable not 1/127 as noticable. ", seems correct.
Using a MIDI monitor to look at 14-bit slider/wheel/knob data reveals what is actually happening. For instance I can move a 14-bit MIDI slider from zero to max as fast as I can, and only get about 20 MIDI messages, ranging from 0,MSB-0,LSB to 127,MSB-127,LSB. It all depends on the scan rate and how the manufacturer decided to implement handling MIDI data. The question changes from why do I get stepping/zippering, to how can it not step/zipper. Simple answer is that, it IS what it IS, digital equals steps, no matter how fine you make them. If you are going from 0 volts to 5 volts in only 20 steps, you are going to hear the steps. Change the range from 0 to 1 volt and those 20 steps are much smoother.
My experience with Moog's handling of 14-bit data, would seem the resolution is 0-255 steps or double that of a standard 0-127 step MIDI CC used on most MIDI synthesizers. But not 128 times the resolution. Would be too much MIDI data for that on any system, no? My best guess it that Moog is handling the LSB like a switch where 0-63 is one value and 64-127 is the next value. So for the Moog filter cut-off that has a range of 0-255 would be something like:
Filter amount 0 = 0,MSB 0-63,LSB
Filter amount 1 = 0,MSB 64-127,LSB
Filter amount 2 = 1,MSB 0-63,LSB
Filter amount 3 = 1,MSB 64-127,LSB
And so on.
At least these are the results I have been getting, still better than only 128 steps. But like you said "The zippering was about as 1/2 as noticable not 1/127 as noticable. ", seems correct.
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Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
Thanks for the info.
I will hook up a midi monitor to check the scanning limits of my BCF2000 controller.
If Moog is using 0-255, that would be 8-bit using the 14-bit protocol, no
A bit (pun intended) cheesy to say that it is sending and recieving 14-bit if it is only 8-bits. Is it an industry standard to say 14-bit CCs, as long as it is using at least one more than 7?
Like you said, digital has it's limitations. I need to come to grips with it or sequence analog (which has it's limitations too).
True 14-bit, 16384 steps, sent and recieved properly, should not be discernible. Even analog CV is stepped at the electron level, but no human could hear that.
I will hook up a midi monitor to check the scanning limits of my BCF2000 controller.
If Moog is using 0-255, that would be 8-bit using the 14-bit protocol, no
A bit (pun intended) cheesy to say that it is sending and recieving 14-bit if it is only 8-bits. Is it an industry standard to say 14-bit CCs, as long as it is using at least one more than 7?
Like you said, digital has it's limitations. I need to come to grips with it or sequence analog (which has it's limitations too).
True 14-bit, 16384 steps, sent and recieved properly, should not be discernible. Even analog CV is stepped at the electron level, but no human could hear that.
Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
I just looked at the output data stream from a Slim Phatty as I turned one of the panel knobs. It is pretty clear that it's using more than 8 bits for ouptut. I can't say whether the same is true for input, but I'd be very surprised if it were not true.
Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
That's great to know. It is most likely the scan rate of the faders on my cheapo controller. The rotary pots allow the user to set the number of ticks per rotation. Hopefully I can get better results with them just for faster sweeps. Then I need to find the limits of my sequencer.
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nathanscribe
- Posts: 58
- Joined: Sat May 10, 2008 12:40 pm
Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
I've had trouble with 14-bit MIDI using my M-audio MIDIsport 8x8, but not my MOTU MIDI Express 128. With the MOTU, the LP sends and receives dense MIDI just fine (running a 2007 iMac with a 2GHz Core 2 Duo and 2.5GB of RAM, and Logic Express 9 to the MOTU via USB). With the M-Audio, things glitch in a noticeable way.
I used to use my LP as a controller keyboard for a rack of stuff, and my old Waldorf XT didn't like the 14-bit input at all. So from my own experience I'd say the LP is happy with all that MIDI. I suspect your Command Station might not be. Are you going Behringer>Sequencer>LP? If so the sequencer could be mis-handling the data even if the fader box is doing OK.
I used to use my LP as a controller keyboard for a rack of stuff, and my old Waldorf XT didn't like the 14-bit input at all. So from my own experience I'd say the LP is happy with all that MIDI. I suspect your Command Station might not be. Are you going Behringer>Sequencer>LP? If so the sequencer could be mis-handling the data even if the fader box is doing OK.
Re: 14-bit zipper just as bad as 7-bit (Filter sweep)
That was the plan, but I've been testing direct bcf into lp.
If the command station causes problems sending the 14 bit thru or causes latency, I can have it set up bcf/cs/lp for recording CCs into the command station then flip it around CS/bcf/lp for performance.
If the command station causes problems sending the 14 bit thru or causes latency, I can have it set up bcf/cs/lp for recording CCs into the command station then flip it around CS/bcf/lp for performance.