[Jack-Devel] How does --hwmon work?

David Kastrup dak at gnu.org
Fri May 5 19:14:52 CEST 2017

Ralf Mardorf <ralf.mardorf at alice-dsl.net> writes:

> On Fri, 05 May 2017 09:42:01 +0200, David Kastrup wrote:
>>Digital control surfaces are everywhere and it's a bit strange that in
>>the Linux DAW world they cannot make it through to the hardware.
> Hi,
> you could mix a song using a control surface and/or automation of
> software such as Ardour. There unlikely is a reason to use a control
> surface and/or automation for hardware monitoring, hdspmixer allows to
> save and load as much presets as you want, 8 presets are available even
> without loading.
> A lot of Linux hardware issues are caused by the missing support of
> the hardware vendors. However, what you want to get is already an
> issue, due to the differences of audio interfaces, even if the vendor
> should support Linux.

Sigh.  Alsa already offers fairly generic access to soundcard mixers
with the alsamixer and amixer commands.

> You expect the recording software to use the audio interface's mixer
> "like this", but if "like this" shouldn't be supported to "fallback to
> that".
> An AIO solution, bundled software + hardware could provide what you
> want to get, in a professional way. I doubt this would work very good,
> if software needs to care about what ever audio interface should be
> connected.

Sigh.  I propose precisely that end user software should _not_ need to
care about whatever audio interface is connected.  That's one of the
points of Jack and ALSA.  Standard APIs to functionality that might be
implemented differently at the driver end.

> A compromise might be to control the DAW mixer and independently to
> control the hardware mixer, too, IOW something like hdspmixer
> controlable by MIDI events. Do a lot of people need it?

Not enough if _every_ _single_ soundcard needs its own mixer application
coded from scratch.  If one creates a common useful Jack API for gained
connections that one mixer application can work with, there will
certainly be enough need to provide a Midi controlled mixer capable of
using hardware mixing where available.

> If so, is somebody willing to add MIDI to e.g. hdspmixer?

The RME Hammerfall is dated (not that it doesn't hold its own pretty
well but you still need to hook it up with preamps and then stuff starts
getting bulky), and hdspmixer is pretty cumbersome to use.  I'd rather
whip up a few Ardour mixers for the connections I actually need and have
them delegate to hardware where feasible.

> EQs, Reverb and delay would be nice for the hardware monitoring, too
> and indeed, proprietary software for a lot of audio interfaces provide
> this.

For hardware monitoring?  Hardly.  At driver level?  Maybe.  But then
it's not fundamentally different to Jack plugins.

David Kastrup

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