View Full Version : Midi Controller Tips
3rd October 2002, 05:06 AM
Hypothetical question : I have a bitstream pro (it rocks). I have a controller that sends midi on channel 1 that controls loop speed. On channel 2 it might control zoom. So I set my speed on channel 1 then switch to channel 2 to further tweak my images.
So I tweak up my zoom on channel 2 but now my controller is set at a different value when I switch my unit back to channel 1. The knob is high but the speed in s/w is still low.
As soon as i touch the knob it sends the value which is high and my speed is all messed up
Is there any way around this issue??
I guess it comes down to intellegent mapping of controllers etc but some midi guru might have an answer for me.
3rd October 2002, 07:11 AM
well, that's the biggest problem on working with midi : it works one-way only. This means that you can only send out info/data to your machinery, but it doesn't work both ways. Only way to have some info back is working with a midi-dump command, but that's not so accurate. I know people don't have the money, so they don't have the choice : midi is about the only thing that's affordable in show-control as it comes on every controller port on a pc. But protocols like RS232 and RS422 are far much better than midi, as you can really 'talk' with your machinery.
3rd October 2002, 07:29 AM
Hmmmm yeah as you can see that really would come down to intellegent mapping of your controls, which is why if your using continuos controllers like knobs, rather than note on off keyboard type stuff your much better off with more controllers and forget all the bank stuff, personally I have 1 midi keyboard and due to a lack of usb2midi adaptor I can't even use it, thats one of the maine reasons I see HIDs like commandpost and DM2 as the way forward, direct input via USB and more setup in a tactile/media friendly manner IE scratching with a jog/disk rather than a slidder or knob.
3rd October 2002, 08:30 AM
yes this is an age old problem.... this is why they invented motor faders and incremental controllers. either need a feedback (of what value it should have) to work properly. The prob is that normal pots/faders convert their position (voltage) to midi value. when the position is no longer the same as the 'virtual controller' you get big jumps in values. motor faders are well expensive, but incremental controllers arent. If you want to keep using faders you will need the motor faders (look into making your own .. www.ucapps.de ) otherwise choose a cheap incremental knob one.
This is one of the reasons I recommend the pocked dial.
14th October 2002, 09:02 AM
The point made by robotfunk is absolutely true.
The best thing (and the most difficult) is to use an bidirectional rs232 controller. Use a programmable altera chipset to work that sliders and knobs.
Also you need to write some C++ to route the rs232 to midi internally.
Damn, it's a lot of work to burn those chips and have a decent board for all your connections.
A colleque is building a rs232-shader unit for proffesional sony cameras, based on the same principle.
He already has 32 knobs, 64 buttons and 16 sliders on one chip, and they all work simultaneously.
When he is finished i will send some basic layouts and ideas for alternative controllers.
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