Re: Micro tuning the AUSampler in iOS
Re: Micro tuning the AUSampler in iOS
- Subject: Re: Micro tuning the AUSampler in iOS
- From: Brian Willoughby <email@hidden>
- Date: Fri, 30 Dec 2011 23:31:08 -0800
The MIDI Specification points out that in some cases a MIDI synth
device will act like 16 virtual instruments, so you have to send Omni
Off on all Channels. Your example message below is for Channel 0,
but you should repeat that for Channels 1 through 15 (BF 7C 00). It
still might not work, but at least it's a complete implementation.
As for the resources, the answer has two parts. Tracking notes and
voice assignments for 16 separate channels as opposed to 1 Omni
channel does not really increase the resource footprint that much.
The actual voices will take more resources if you are to hear them
all, but standard voice allocation methods can be used to match the
notes requested to the voices that are available. Any synth can
simply truncate sounds that exceed its synthesis ability.
Brian Willoughby
Sound Consulting
On Dec 30, 2011, at 19:50, Lukas Bühler wrote:
Thanks for the help, that looked like the thing I was looking for!
So I read up on modes and poly and set the mode change messages to
omni off (B0 7C 00), but to no effect...
I really wonder if the iOS AUSampler supports omni off /poly? It
would use quite some resources, so maybe Apple has does not support
it?
Any other ideas?
On Fri, Dec 30, 2011 at 8:01 PM, Brian Willoughby
<email@hidden> wrote:
Are you familiar with the MIDI Specification for Channel Modes?
The default "power-up" conditions are recommended as Channel 1,
Omni On/Poly, otherwise known as Mode 1. In this mode, the
channel number is basically ignored, which would seem to explain
why your pitch bend messages are affecting all channels.
I recommend that you send a Channel Mode message to select Omni
Off. You should certainly do this at startup or whenever a new
MIDI destination is selected, and perhaps also after a preset
change. If this does not solve your problem, then look deeper
into the MIDI Specification, starting with Poly/Mono and related
modes.
On Dec 30, 2011, at 15:30, Lukas Bühler wrote:
I'm developing an iOS instrument using the UASampler audio unit
and I want to support micto tuning. Currently I'm playing each
note in a different channel and I send pitch bend MIDI messages
to micro tune that note. What happens though is that all channels
are pitch bend not just the one I send the bend message to.
Does the AUSampler not support pitch bend on the individual
channels? Anybody know how to do this?
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