Re: [LAD] "Open midi-keyboard"

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To: <ralf.mardorf@...>, <jens.andreasen@...>
Cc: <linux-audio-dev@...>
Date: Saturday, September 26, 2009 - 10:28 pm

<4ABDF9FC.5040105@rncbc.org> <4ABE0324.1010005@alice-dsl.net>

<1253998090.13534.35.camel@c80-216-240-74.bredband.comhem.se>

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<4ABE8312.2000006@alice-dsl.net>
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I would not put too much emphasis on the ms delays and traffic volume
generated by these messages. It has been generally agreed that the bandwidt=
h
of MIDI would have killed it a long time ago had it not been for 'integrate=
d'
systems that passed MIDI internally hence had no bandwidth limitations and
that MIDI/USB is keeping it alive today. The device you are talking about h=
as
a USB connector which can be used at a later date when you need bandwidth
so perhaps concentrate on functionality for now? Just a suggestion.

A bigger problem regarding pressure is whether the device can support eithe=
r
channel or poly pressure. There are surprisingly few that support poly pres=
sure
as the hardware required to do it (sensors under each key) is still exorbit=
antly
expensive and also pretty heavy. OK=2C it can be done cheaply as well howev=
er=20
the cheaper hardware gives two problems that make it's use difficult:

a. it can be overly sensitive so difficult to control
b. it is generally low resolution so you hear each step in pressure change

Velocity sensing by contrast typically just uses two space separate contact=
s=20
and some high speed key scanning - very cheap and cheerful. And portable.

Any hardware that can do velocity sensing for note on can also do it for no=
te
off events if suitable software coding is done. Whether a synth can track t=
he
note off velocity is variable and there are naturally good and bad targets =
for
note-off velocity:

Bad targets:
Volume/gain=2C filter cutoff=2C FX depths=2C : All of these might be normal=
for
note-on velocity but are very bad selections for note-off. They cause pops=
=20
and clicks when key-on velocity is very different from key-off velocity.

Potentially good targets:
ADSR release rate.=20
Exceptional processing (bv. piano damping effects).
LFO speeds

I think one of the reasons that many synths have avoided doing anything
with note-off velocity is that the typical targets are not the same as with=
=20
note-on velocity hence there are some semantic issues associated with how
they need to be directed. Most synths have 'velocity sensitivity'=2C but if=
it is so
glib that both values control the same parameter then the results will not =
be
what you are probably expecting: they should vary rarely be directed to the
same synth parameter.

Kind regards=2C nick.

"we have to make sure the old choice [Windows] doesn't disappear=94.
Jim Wong=2C president of IT products=2C Acer

> Date: Sat=2C 26 Sep 2009 23:09:38 +0200

be
=20
s=20
=20
e=20
=20
=20
=2C=20
=0A=
_________________________________________________________________=0A=
More than messages=96check out the rest of the Windows Live=99.=0A=
http://www.microsoft.com/windows/windowslive/=

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I would not put too much emphasis on the ms delays and traffic volumege=
nerated by these messages. It has been generally agreed that the bandwidth<=
br>of MIDI would have killed it a long time ago had it not been for 'integr=
ated'systems that passed MIDI internally hence had no bandwidth limitat=
ions andthat MIDI/USB is keeping it alive today. The device you are tal=
king about hasa USB connector which can be used at a later date when yo=
u need bandwidthso perhaps concentrate on functionality for now? Just a=
suggestion.A bigger problem regarding pressure is whether the devi=
ce can support eitherchannel or poly pressure. There are surprisingly f=
ew that support poly pressureas the hardware required to do it (sensors=
under each key) is still exorbitantlyexpensive and also pretty heavy. =
OK=2C it can be done cheaply as well however the cheaper hardware gives=
two problems that make it's use difficult:a. it can be overly sens=
itive so difficult to controlb. it is generally low resolution so you h=
ear each step in pressure changeVelocity sensing by contrast typica=
lly just uses two space separate contacts and some high speed key scann=
ing - very cheap and cheerful. And portable.Any hardware that can d=
o velocity sensing for note on can also do it for noteoff events if sui=
table software coding is done. Whether a synth can track thenote off ve=
locity is variable and there are naturally good and bad targets fornote=
-off velocity:Bad targets:Volume/gain=2C filter cutoff=2C FX de=
pths=2C : All of these might be normal fornote-on velocity but are very=
bad selections for note-off. They cause pops and clicks when key-on ve=
locity is very different from key-off velocity.Potentially good tar=
gets:ADSR release rate. Exceptional processing (bv. piano damping e=
ffects).LFO speedsI think one of the reasons that many synths h=
ave avoided doing anythingwith note-off velocity is that the typical ta=
rgets are not the same as with note-on velocity hence there are some se=
mantic issues associated with howthey need to be directed. Most synths =
have 'velocity sensitivity'=2C but if it is soglib that both values con=
trol the same parameter then the results will not bewhat you are probab=
ly expecting: they should vary rarely be directed to thesame synth para=
meter.Kind regards=2C nick."we have to make sure the old ch=
oice [Windows] doesn't disappear=94.Jim Wong=2C president of IT product=
s=2C Acer&gt=3B Date: Sat=2C 26 Sep 2009 23:09:38 +0200=
&gt=3B From: ralf.mardorf@alice-dsl.net&gt=3B To: jens.andreasen@co=
mhem.se&gt=3B CC: linux-audio-dev@lists.linuxaudio.org&gt=3B Subjec=
t: Re: [LAD] "Open midi-keyboard"&gt=3B &gt=3B &gt=3B &gt=3B Je=
ns M Andreasen wrote:&gt=3B &gt=3B&gt=3B On Sat=2C 2009-09-26 at 14:03 =
+0200=2C Ralf Mardorf wrote:&gt=3B &gt=3B&gt=3B&gt=3B &gt=3B&gt=3B =
&gt=3B &gt=3B&gt=3B&gt=3B When using several MIDI ports even a lot of =
SysEx can be sent &gt=3B &gt=3B&gt=3B&gt=3B real-time=2C but using only=
one MIDI port even aftertouch can cause &gt=3B &gt=3B&gt=3B&gt=3B timi=
ng problems. &gt=3B &gt=3B&gt=3B&gt=3B &gt=3B&gt=3B A stream of=
channel-aftertouch is single bytes=2C and can at any point be&gt=3B &g=
t=3B&gt=3B interrupted by more important data (note-on) with at most 0.3&gt=3B &gt=3B&gt=3B miliseconds delay ...&gt=3B &gt=3B&gt=3B &gt=
=3B When interrupted it's 2 bytes=2C one byte only when running status can =
&gt=3B &gt=3B take effect. To be honest=2C I don't know if aftertouch w=
ill be &gt=3B &gt=3B interrupted by applications and devices by default=
. Is this MIDI &gt=3B &gt=3B standard? And to be honest=2C much more da=
ta is produced by the pitch &gt=3B &gt=3B wheel=2C because of the low a=
nd high byte. I never had any timing issues &gt=3B &gt=3B because of af=
tertouch and pitch bend=2C but I noticed that they produce &gt=3B &gt=
=3B much more traffic than real-time SysEx for filters. IIRC I had 4 MIDI <=
br>&gt=3B &gt=3B outputs for the Atari ST=2C I guess using just one MIDI ou=
tput can cause &gt=3B &gt=3B trouble for pure MIDI music.&gt=3B &gt=
=3B&gt=3B &gt=3B Ralf&gt=3B &gt=3B Yes=2C the Midex had 4 MIDI =
outs.&gt=3B &gt=3B Have you tested heavy traffic with just one MIDI=
port?&gt=3B &gt=3B I can't speak for aftertouch=2C but SysEx can b=
ecome problematic. Okay=2C &gt=3B SysEx always needs to be transmitted =
from $F0 to $F7=2C while aftertouch &gt=3B can be interrupted=2C anyway=
=2C aftertouch can cause really a lot of data=2C &gt=3B much more than =
SysEx for filters.&gt=3B ______________________________________________=
_&gt=3B Linux-audio-dev mailing list&gt=3B Linux-audio-dev@lists.li=
nuxaudio.org&gt=3B http://lists.linuxaudio.org/mailman/listinfo/linux-a=
udio-dev check out the rest of the Windows Live=
=99.
More than mail=96Windows Live=99 goes way beyond your inbox.
=
More than messages

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Messages in current thread:
[LAD] "Open midi-keyboard", Albin Stigo, (Fri Sep 25, 3:07 pm)
Re: [LAD] "Open midi-keyboard", Carlo Capocasa, (Sat Oct 3, 1:10 pm)
Re: [LAD] "Open midi-keyboard", Fons Adriaensen, (Sat Sep 26, 11:36 am)
Re: [LAD] "Open midi-keyboard", David Olofson, (Mon Sep 28, 6:40 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 12:21 pm)
Re: [LAD] "Open midi-keyboard", David Olofson, (Mon Sep 28, 6:42 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Mon Sep 28, 7:01 pm)
Re: [LAD] "Open midi-keyboard", Fons Adriaensen, (Sat Sep 26, 1:07 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 1:55 pm)
Re: [LAD] "Open midi-keyboard", Peter Nelson, (Sat Sep 26, 12:41 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 12:53 pm)
Re: [LAD] "Open midi-keyboard", Jörn Nettingsmeier, (Sun Sep 27, 11:58 am)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sun Sep 27, 12:25 pm)
Re: [LAD] "Open midi-keyboard", Christian, (Fri Sep 25, 3:30 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 11:07 am)
Re: [LAD] "Open midi-keyboard", Rui Nuno Capela, (Sat Sep 26, 11:29 am)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 12:03 pm)
Re: [LAD] "Open midi-keyboard", Jens M Andreasen, (Sat Sep 26, 8:50 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 9:03 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 9:10 pm)
Re: [LAD] "Open midi-keyboard", Nick Copeland, (Sat Sep 26, 10:28 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sat Sep 26, 10:56 pm)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sun Sep 27, 12:24 am)
Re: [LAD] "Open midi-keyboard", Fons Adriaensen, (Sun Sep 27, 9:14 am)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sun Sep 27, 11:00 am)
Re: [LAD] "Open midi-keyboard", Fons Adriaensen, (Sun Sep 27, 11:38 am)
Re: [LAD] "Open midi-keyboard", Ralf Mardorf, (Sun Sep 27, 12:07 pm)
Re: [LAD] "Open midi-keyboard", rosea grammostola, (Fri Sep 25, 3:38 pm)