1 Jun
2018
1 Jun
'18
11 p.m.
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer to computer
rather than between hardware devices. So do you get lower latency?
Also what about keyboards that work entirely as MIDI over USB connecting to a
computer?
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
1 Jun
1 Jun
11:58 p.m.
Will Godfrey <willgodfrey(a)musically.me.uk> writes:
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer
to computer rather than between hardware devices. So do you get lower
latency?
Computers don't generally act as USB clients but as hosts. This is not
Firewire. Not applicable.
Also what about keyboards that work entirely as MIDI
over USB
connecting to a computer?
USB Low speed is 1.5Mbps and half-duplex. Midi can be transmitted over
16 logical connectors as 32bit packets of bulk data containing a payload
of up to 3 bytes. If you've kept up until here, you'll find that this
starts sounding fishy but then when trying to exercise all connectors,
we'd more likely be using full speed at 12Mbps (I have a Roland UM-4
Midi interface with 4 in and 4 out Midi connectors and it uses full
speed) Which is fine as long as we are not sharing the same hub with low
speed devices such as mice and keyboards and/or the hub does not have
just a single "transaction translator" for USB 1.1 compatibility in
which case Midi packets are blocked while the low-speed devices get
their data through,
So (deep breath) usually you should be fine. There may be rare
circumstances when you aren't and they can usually be fixed by
connecting things differently.
--
David Kastrup
2 Jun
2 Jun
12:50 a.m.
On 06/01/2018 09:00 PM, Will Godfrey wrote:
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer to computer
rather than between hardware devices. So do you get lower latency?
You have more bandwidth but not usually lower latency.
Also what about keyboards that work entirely as MIDI
over USB connecting to a
computer?
Depends on the keyboard.
It seems that may chipsets still use the 31.25kbaud (probably because
you can get USB to physical MIDI ASIC cheap off the shelf).
You can check with jack_midi_dump (or similar). Elbow press/release
30-40 notes on a keyboard and check if most individual note events are
spaced less than 1ms apart. If they are, then the interface is faster
than physical MIDI.
ciao,
robin
1:45 a.m.
On Fri, 1 Jun 2018 22:50:50 +0200
Robin Gareus <robin(a)gareus.org> wrote:
On 06/01/2018 09:00 PM, Will Godfrey wrote:
Now why didn't I think of that?
Thanks Robin :)
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer to computer
rather than between hardware devices. So do you get lower latency?
You have more bandwidth but not usually lower latency.
Also what about keyboards that work entirely as
MIDI over USB connecting to a
computer?
Depends on the keyboard.
It seems that may chipsets still use the 31.25kbaud (probably because
you can get USB to physical MIDI ASIC cheap off the shelf).
You can check with jack_midi_dump (or similar). Elbow press/release
30-40 notes on a keyboard and check if most individual note events are
spaced less than 1ms apart. If they are, then the interface is faster
than physical MIDI.
ciao,
robin
2:13 a.m.
On 06/01/2018 11:45 PM, Will Godfrey wrote:
On Fri, 1 Jun 2018 22:50:50 +0200
Robin Gareus <robin(a)gareus.org> wrote:
I just tested with a M-Audio Oxygen 49 (which only has USB MIDI)
I've used an A4-book to press/release 14 white keys, recorded it with
Ardour. The 14 note-off events span 220 samples (@48kHz, ~4.5ms).
So the device has a higher bandwidth than physical MIDI (approx 3
times). I can't say anything about the latency though.
All other devices that I have here do have an physical MIDI port (5pin
DIN) and are only 31.25 kbaud have ~2.0ms round-trip latency.
Cheers!
robin
PS. note-on events are spread out further because I didn't manage to
press the book (or elbow) down accurately enough.
On 06/01/2018 09:00 PM, Will Godfrey wrote:
Now why didn't I think of that?
Thanks Robin :)
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer to computer
rather than between hardware devices. So do you get lower latency?
You have more bandwidth but not usually lower latency.
Also what about keyboards that work entirely as
MIDI over USB connecting to a
computer?
Depends on the keyboard.
It seems that may chipsets still use the 31.25kbaud (probably because
you can get USB to physical MIDI ASIC cheap off the shelf).
You can check with jack_midi_dump (or similar). Elbow press/release
30-40 notes on a keyboard and check if most individual note events are
spaced less than 1ms apart. If they are, then the interface is faster
than physical MIDI.
ciao,
robin
2:32 a.m.
On Sat, 2 Jun 2018 00:12:58 +0200
Robin Gareus <robin(a)gareus.org> wrote:
On 06/01/2018 11:45 PM, Will Godfrey wrote:
That is actually very interesting, and useful.
With hardware MIDI a two-handed 4 note chord (so 8 total) has a 'ripple' of at
at the very least 8mS. Although a musician is likely to be more varied than
that, something like a drum machine wont, and this effect can be very noticable.
it would suggest that where you have a keyboard with both options you should
use USB for preference.
I have a Miditech pro49 that has that combination, so must check to see if
that's true, or if the two outputs are locked together.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
On Fri, 1 Jun 2018 22:50:50 +0200
Robin Gareus <robin(a)gareus.org> wrote:
I just tested with a M-Audio Oxygen 49 (which only has USB MIDI)
I've used an A4-book to press/release 14 white keys, recorded it with
Ardour. The 14 note-off events span 220 samples (@48kHz, ~4.5ms).
So the device has a higher bandwidth than physical MIDI (approx 3
times). I can't say anything about the latency though.
All other devices that I have here do have an physical MIDI port (5pin
DIN) and are only 31.25 kbaud have ~2.0ms round-trip latency.
Cheers!
robin
PS. note-on events are spread out further because I didn't manage to
press the book (or elbow) down accurately enough. On 06/01/2018 09:00 PM, Will Godfrey wrote:
Now why didn't I think of that?
Thanks Robin :)
Something just occurred to me.
Does anyone know if this is transmitted any faster if going computer to computer
rather than between hardware devices. So do you get lower latency?
You have more bandwidth but not usually lower latency.
Also what about keyboards that work entirely as
MIDI over USB connecting to a
computer?
Depends on the keyboard.
It seems that may chipsets still use the 31.25kbaud (probably because
you can get USB to physical MIDI ASIC cheap off the shelf).
You can check with jack_midi_dump (or similar). Elbow press/release
30-40 notes on a keyboard and check if most individual note events are
spaced less than 1ms apart. If they are, then the interface is faster
than physical MIDI.
ciao,
robin
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days inactive
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participants (3)
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Robin Gareus -
Will Godfrey