Resolution/speed: Multiplexing vs external midi controller

#1

Hi. If i want to have more analog inputs (potmeters) connected to the Axoloti, than it currently supports, I could go about this in 2 ways:
-Add a multiplexer board
-Buy a Doepfer USB64

Multiplexing:
Axoloti scans the analog input at 3khz. If i do multiplexing, will the multiplexer board scan all my knobs at a lower rate than 3khz, and then effectively, give me a much lower rate than 3khz? What rate?

USB64:
Its only 7 bit data. Which will give me the best resolution? 7 bit midi or the analog in, via a multiplexer?

Or does it matter at all? Do i just smooth the incoming 7 bit midi values, and then all is good?

Im planning on making a virtual analog synth. The pots are for filter cutoff/osc tuning etc.

Thanks:)

#2

iirc the analog is converted to 12 bit.

does it matter? depends on what your using it for... and how much control you want.
you will be able to feel the steps if you try...

7 bit is pretty coarse, but hey, many people are happy enough with it. (most midi controllers are 7bit, though more expensive ones are more)

imagine a small knob, can you select 1/128th of a step? and do you need it more precise than that?
but on a huge cutoff knob, you would easily select that...

could you hear the difference? on somethings unlikely, but if you had a big knob and you were doing a detune on two oscillators, or doing FM, yes, because small changes are pretty audible.

so all comes down to , you pay your money you take your choice :smile:

(I'll admit when I looked at the USB64, I was disappointed it didn't have a 14 bit option)

#3

Thanks!:smile: No definite answer i guess. But found out the ainser64 outputs 12 bit data somehow.. How can this be done? Isnt the speed/resolution divided up between the 8 analog inputs being scanned?

So i guess the answer is that the ainser64 module is outputting 12 bits. The Axolot is scanning at 12 bits. Thats 4096 vs midi 127. Seems like the Ainser64 is the answer then:)
But im also guessing that all that scanning comes at a price (cpu usage). Still waiting for my axoloti to come in the mail.

Thanks again.

#4

looks interesting, but just noticed this:

10 bits is still good, 0-1023

Id disagree about, Pitchbend, midi pitchbend is 14 bit for good reason, in particular if you use larger pitchebend ranges.

#5

10 bit is still way better than 127. So fine for me:) I'll be using an external keyboard for this, and will be plugging it directly to the midi input of the axoloti, so no biggie for me.
Thanks for your inputs!