25 Aug
2015
25 Aug
'15
9:23 a.m.
Hi List,
for a project at work (nothing to do with music, sadly, but at least audio)
I'm looking for an audio interface that supports at least 16bit/48kHz
(24bit/96kHz would be even better, we're potentially looking for rather
high frequency signals...) for two mics that need phantom power and where
the preamp gain can be controlled remotely by software, as this will be
used as follows:
The whole setup will be mounted at a remote location inside a larger
machinery for audio surveillance of said machinery (fault detection etc.).
The larger machinery of course may not be running while opened to install
our setup, thus setting the gain has to be done remotely.
The PC in this setup has an x86_64 CPU running Ubuntu 12.04 LTS, but the
case is too small for PCI(e) solutions, doesn't have firewire, so the only
option is USB.
For our current setup we have a Focusrite Scarlett 2i2 here, but there's no
way to set the mic gain via software :-/
Researching so far led me to the RME Babyface that is said to be supported
when in class compliant mode - but you seem to need to hold down buttons
while turning it on, which is a problem as we can't open up the larger
machinery every time the hardware needs to be restarted.
Is anyone here aware of something we could use here?
Thanks in advance,
Thomas
25 Aug
25 Aug
10:21 a.m.
New subject: Searching for audio interface with software-controlled mic gain
On 08/25/2015 09:23 AM, Thomas Janu wrote:
Researching so far led me to the RME Babyface that is
said to be supported
when in class compliant mode - but you seem to need to hold down buttons
while turning it on, which is a problem as we can't open up the larger
machinery every time the hardware needs to be restarted.
You can't control the mic gain of the RME Babyface from Linux. It has to
be done on the device itself. Besides, when using the RME Babyface in
class compliant mode it is not possible at all to control anything
remotely as RME does this with its proprietary, closed driver which gets
disabled when using class compliant mode. This is also the reason why
the RME Babyface only works in CC mode with Linux as the RME driver is
not available for Linux. To set the Babyface in CC mode you only have to
push down two buttons at startup once. After that it will stay in CC
mode on consecutive reboots.
Jeremy
10:33 a.m.
New subject: Searching for audio interface with software-controlled mic gain
Thomas Janu <thomas.janu(a)gmail.com> schrieb am Di., 25. Aug. 2015 um
09:23 Uhr:
Hi List,
for a project at work (nothing to do with music, sadly, but at least
audio) I'm looking for an audio interface that supports at least
16bit/48kHz (24bit/96kHz would be even better, we're potentially looking
for rather high frequency signals...) for two mics that need phantom power
and where the preamp gain can be controlled remotely by software,
I'm using a Behringer XR18 for a couple of months now and I'm pretty happy
with it (*). I have not really used it for recording though besides running
some simple tests. It's 24bit/48kHz AFAICT, its frequency range 10 Hz - 22
kHz.
It is primarily a rack mixer that doubles as a class compliant audio
interface. Everything can be remotely controlled via their control apps for
Linux/Mac/Windows/Android/iOS (**) and via OSC.
The smaller versions XR12/XR16 lack the audio interface.
I use it as a mixer on stage. The audio interface is only used for playback
purposes at the moment. But if you have concrete questions that I might be
able to answer with a reasonable amount of testing time I'll gladly help.
Kind regards,
Felix
(*)
Documentation is awful/not present. Behringer will delete any kind of
criticism on its forum, especially when it comes to critcising not
delivering on their own and their CEO's claims and promises in time. There
still seem to be some bugs in the firmware, like wrong parameter bindings
for some effects. My first device had defect pre-amps on 2 inputs but was
immediately replaced by the seller. *Do not* rely on the internal router,
you'd better not use it at all.
(**)
The desktop apps are full featured on every OS while the mobile apps differ
in a small set of features currently.
11:24 a.m.
New subject: Searching for audio interface with software-controlled mic gain
On Tue, 25 Aug 2015 08:33:25 +0000, Felix Homann wrote:
Everything can be remotely controlled via their control
apps for
Linux/Mac/Windows/Android/iOS (**) and via OSC.
But you should download Behringer apps immediately. I didn't download
an app for a Behringer device when I bought it. One or two years later
I wanted to download the app, but since the device is discontinued,
they didn't provide the app anymore. Writing to Behringer is useless,
you never will get a reply.
11:59 a.m.
New subject: Searching for audio interface with software-controlled mic gain
Ralf Mardorf <ralf.mardorf(a)alice-dsl.net> schrieb am Di., 25. Aug. 2015 um
11:24 Uhr:
But you should download Behringer apps immediately. I didn't download
an app for a Behringer device when I bought it. One or two years later
I wanted to download the app, but since the device is discontinued,
they didn't provide the app anymore. Writing to Behringer is useless,
you never will get a reply.
Please, let's try to *not* make this a Behringer discussion. They do have
their "not that good" reputation for a reason. I think that's pretty clear
for everybody. They have won back a lot of respect with their X32 series;
most everyone agrees on this, too. They are still not "there", yet; that's
my personal opinion.
For the case of discontinued software: There's no secret soup in how the
device is controlled. It is all OSC. And actually, I'm already using it
more with my own software than with theirs.
BTW, for my use case, there simply is no alternative to the XR18 on the
market besides the Behringer X32 Rack. Chosing between those two was a
matter of weight (+3kg for the X32 Rack). I have been waiting for a
lightweight, rack mountable, and easily remote controllable rack mixer for
years and would have taken anything with a price up to 2000 EUR from
whoever came first ;-)
Regards,
Felix
12:27 p.m.
New subject: Searching for audio interface with software-controlled mic gain
On Tue, 25 Aug 2015 09:59:25 +0000, Felix Homann wrote:
Ralf Mardorf schrieb am Di., 25. Aug. 2015 um 11:24
Uhr:
I still buy Behringer equipment myself.
Anyway, it's important to mention that apps might not be supported for
a long time.
Btw. I don't know how long Behringer specific replacement parts are
available.
I don't want to discuss Behringer, but I guess we should make the OP
aware of the Behringer policy. The OP likely is able to decide, if the
information is from relevance.
The quality of Behringer products wasn't mentioned by me, but since the
OP wants to remote control input levels, software support/maintenance
might be relevant.
;)
But you should download Behringer apps
immediately.
Please, let's try to *not* make this a Behringer discussion.
12:23 p.m.
New subject: Searching for audio interface with software-controlled mic gain
On Tue, Aug 25, 2015 at 10:33 AM, Felix Homann <linuxaudio(a)showlabor.de>
wrote:
Thomas Janu <thomas.janu(a)gmail.com> schrieb am
Di., 25. Aug. 2015 um
09:23 Uhr:
This thing looks rather promising, thanks a lot!
Hi List,
for a project at work (nothing to do with music, sadly, but at least
audio) I'm looking for an audio interface that supports at least
16bit/48kHz (24bit/96kHz would be even better, we're potentially looking
for rather high frequency signals...) for two mics that need phantom power
and where the preamp gain can be controlled remotely by software,
I'm using a Behringer XR18 for a couple of months now and I'm pretty happy
with it (*). I have not really used it for recording though besides running
some simple tests. It's 24bit/48kHz AFAICT, its frequency range 10 Hz - 22
kHz.
It is primarily a rack mixer that doubles as a class compliant audio
interface. Everything can be remotely controlled via their control apps for
Linux/Mac/Windows/Android/iOS (**) and via OSC.
The smaller versions XR12/XR16 lack the audio interface.
I use it as a mixer on stage. The audio interface is only used for
playback purposes at the moment. But if you have concrete questions that I
might be able to answer with a reasonable amount of testing time I'll
gladly help.
So if I understand this correctly there is a USB connection for audio and
one would need an additional ethernet or wifi connection for controlling it?
The only things I'm interested in here is the control of the various gains
and a two channel recording - seems like that could easily be done with
this thing.
I'm guessing the audio interface is class compliant and simply exposes all
18x18 channels via alsa?
Kind regards,
Felix
(*)
Documentation is awful/not present. Behringer will delete any kind of
criticism on its forum, especially when it comes to critcising not
delivering on their own and their CEO's claims and promises in time. There
still seem to be some bugs in the firmware, like wrong parameter bindings
for some effects. My first device had defect pre-amps on 2 inputs but was
immediately replaced by the seller. *Do not* rely on the internal router,
you'd better not use it at all.
You mean the internal Wi-Fi router?
Thanks again,
Thomas
12:49 p.m.
New subject: Searching for audio interface with software-controlled mic gain
Thomas Janu <thomas.janu(a)gmail.com> schrieb am Di., 25. Aug. 2015 um
12:24 Uhr:
So if I understand this correctly there is a USB
connection for audio and
one would need an additional ethernet or wifi connection for controlling it?
Yes, that's the way you're usually working with it. There is some support
for controlling it via USB/MIDI directly but AFAIK it is limited and
software wise you'd be very much on your own. I vae not tested it. Mackie
protocol support is advertised but not implemented (yet?).
The only things I'm interested in here is the
control of the various gains
and a two channel recording - seems like that could easily be done with
this thing.
Yes, very easily.
I'm guessing the audio interface is class
compliant and simply exposes all
18x18 channels via alsa?
Yes.
--Felix
5:28 p.m.
New subject: Searching for audio interface with software-controlled mic gain
* Felix Homann <linuxaudio(a)showlabor.de> [2015-08-25 06:49]:
[...]
And how are the 18 channels that are sent from the host computer to the
device mapped to hardware outputs? There are only 8 outputs visible on
pictures of the device.
Does the device have a fan?
Thanks,
I'm
guessing the audio interface is class compliant and simply exposes all
18x18 channels via alsa?
Yes.
5:57 p.m.
New subject: Searching for audio interface with software-controlled mic gain
Peter P. <peterparker(a)fastmail.com> schrieb am Di., 25. Aug. 2015 um
17:28 Uhr:
No, it doesn't.
Kind regards,
Felix
(*)
Channel 17/18, aka "Aux", is special as it is stereo linked and reserved
for the stereo Line in (17/18) as analog input. you can not route other
analog inputs to this mixing channel. You can still route any USB Return to
the Aux channel.
And how are the 18 channels that are sent from the host computer to
the device mapped to hardware outputs? There are only 8 outputs visible
on pictures of the device.
In Behringer terminology the device has 18 mixing channels, 18 analog
inputs, 18 USB returns and 18 USB outputs. The "channels that are sent from
the host computer to the device" are the "USB returns".
You can route any of the analog inputs or USB returns to any mixing
channel(*). In the other direction, you can route a multitude of sources
(channels, busses, FX L/R, FX Sends, Main L/R) with a lot of tap points
(Pre EQ, Post EQ, Pre Fader etc.) to any of the USB outputs ("those
channels that are sent to the host computer").
Does the device have a fan?
6:05 p.m.
New subject: Searching for audio interface with software-controlled mic gain
* Felix Homann <linuxaudio(a)showlabor.de> [2015-08-25 11:57]:
Peter P. <peterparker(a)fastmail.com> schrieb am
Di., 25. Aug. 2015 um
17:28 Uhr:
No, it doesn't.
Kind regards,
Felix
Thank you for this wonderful explanation Felix!
And how are the 18 channels that are sent from the host computer to
the device mapped to hardware outputs? There are only 8 outputs visible
on pictures of the device.
In Behringer terminology the device has 18 mixing channels, 18 analog
inputs, 18 USB returns and 18 USB outputs. The "channels that are sent from
the host computer to the device" are the "USB returns".
You can route any of the analog inputs or USB returns to any mixing
channel(*). In the other direction, you can route a multitude of sources
(channels, busses, FX L/R, FX Sends, Main L/R) with a lot of tap points
(Pre EQ, Post EQ, Pre Fader etc.) to any of the USB outputs ("those
channels that are sent to the host computer").
Does the device have a fan?
6:12 p.m.
New subject: Searching for audio interface with software-controlled mic gain
On Tue, 25 Aug 2015 11:28:44 -0400, Peter P. wrote:
And how are the 18 channels that are sent from the host
computer to the
device mapped to hardware outputs? There are only 8 outputs visible on
pictures of the device.
Regarding the Behringer Wiki "The mixer application allows assignment
of channels for recording and playback",
http://behringerwiki.music-group.com/index.php?title=2.1_X18/XR18_Callouts
3:29 p.m.
New subject: Searching for audio interface with software-controlled mic gain
On Tue, 25 Aug 2015, Thomas Janu wrote:
for a project at work (nothing to do with music,
sadly, but at least audio) I'm
looking for an audio interface that supports at least 16bit/48kHz (24bit/96kHz
would be even better, we're potentially looking for rather high frequency
signals...) for two mics that need phantom power and where the preamp gain can be
controlled remotely by software, as this will be used as follows:
The limiting factors for frequency/headroom are generally in the analog
portion of things. 16bits already comes close to the limits of most analog
hw. 96k SR will not give you up to 48k audio recording in most cases of
equipment built for audio use. An interface built for osciliscope use may
be better, though likely less than 16 bit and would require some custom
circuitry for your application.
So long as 20 to 20k will work for you an audio interface will work.
This one: http://www.motu.com/products/avb/ultralite-avb is USB2.0 class
compliant and can be remote controled via web interface (through ethernet
connector on back). Seems overkill though. But then so does the xair18...
Note that I have not had either of these boxes in my hand, I suggest, as
always, taking a linux laptop to the music store and trying it out there.
--
Len Ovens
www.ovenwerks.net
26 Aug
26 Aug
8:41 a.m.
New subject: Searching for audio interface with software-controlled mic gain
Good morning,
On Tue, Aug 25, 2015 at 3:28 PM, Len Ovens <len(a)ovenwerks.net> wrote:
This one:
http://www.motu.com/products/avb/ultralite-avb is USB2.0 class
compliant and can be remote controled via web interface (through ethernet
connector on back). Seems overkill though. But then so does the xair18...
Thanks for that, now I at least have two options.
And you're right, they're both overkill (and the xair18 might be too big,
there's not much room in that machinery where it will be mounted - but I
haven't seen that yet).
Maybe I can find something like a remotely controllable mic preamp and just
keep the 2i2's inputs at line level...
Thanks,
Thomas
4 Sep
4 Sep
10 a.m.
New subject: Searching for audio interface with software-controlled mic gain
Hi Thomas,
Sorry to dig up this oldish discussion and if I missed some of the
ideas.. but it's actually quite interesting.
On 25/08/2015 09:23, Thomas Janu wrote:
[...]
The whole setup will be mounted at a remote location inside a larger
machinery for audio surveillance of said machinery (fault detection
etc.). The larger machinery of course may not be running while opened to
install our setup, thus setting the gain has to be done remotely.
The PC in this setup has an x86_64 CPU running Ubuntu 12.04 LTS, but the
case is too small for PCI(e) solutions, doesn't have firewire, so the
only option is USB.
Does the audio interface *have* to be inside the machine as well? What I
mean is Couldn't you just have the mics in the machine and the audio
interface outside (and accessible) so as to possible set the gain, fine
tune, turn on/off etc.?
Maybe I totally misunderstood the set-up but if what I wrote above were
somewhat feasible you might drop altogether the software-controlled gain
requirement?
Lorenzo.
10:38 a.m.
New subject: Searching for audio interface with software-controlled mic gain
Hi Lorenzo,
On Fri, Sep 4, 2015 at 10:00 AM, Lorenzo Sutton <lorenzofsutton(a)gmail.com>
wrote:
Hi Thomas,
Sorry to dig up this oldish discussion and if I missed some of the ideas..
but it's actually quite interesting.
No problem - it's still not solved on our side, as the two solutions so far
were deemed too expensive for a test setup by my higher-ups.
On 25/08/2015 09:23, Thomas Janu wrote:
[...]
Sadly, it has to be inside. The bigger machine it's to be mounted in is
itself stationary and outside, and not exactly at ground level. There's
sadly no feasible way to have our stuff outside of the enclosure. If it
were, the cables would be on the order of ~100m and the stuff outside the
machinery would need to be secured against weather and - more importantly -
humans that have nothing to do with it, as it would be publicly accessible.
As there is a climb involved, repeatedly turning the machine on, checking
the levels, turning the machine off, climbing up, adjusting the levels,
climbing down, turning the machine on, ... is also not feasible.
Thanks,
Thomas
The whole setup will be mounted at a remote location inside a larger
machinery for audio surveillance of said machinery (fault detection
etc.). The larger machinery of course may not be running while opened to
install our setup, thus setting the gain has to be done remotely.
The PC in this setup has an x86_64 CPU running Ubuntu 12.04 LTS, but the
case is too small for PCI(e) solutions, doesn't have firewire, so the
only option is USB.
Does the audio interface *have* to be inside the machine as well? What I
mean is Couldn't you just have the mics in the machine and the audio
interface outside (and accessible) so as to possible set the gain, fine
tune, turn on/off etc.?
11:17 a.m.
New subject: Searching for audio interface with software-controlled mic gain
On Fri, 4 Sep 2015 10:38:54 +0200
Thomas Janu <thomas.janu(a)gmail.com> wrote:
Hi Lorenzo,
On Fri, Sep 4, 2015 at 10:00 AM, Lorenzo Sutton <lorenzofsutton(a)gmail.com>
wrote:
How about a Heath-Robinson solution?
Hook up an Arduino-mini (or the like) to voltage or digitally controlled
amplifiers and link it into the computer via USB. If that's not possible run an
external RS232 serial line to it.
--
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.
Hi Thomas,
Sorry to dig up this oldish discussion and if I missed some of the ideas..
but it's actually quite interesting.
No problem - it's still not solved on our side, as the two solutions so far
were deemed too expensive for a test setup by my higher-ups. 
11:58 a.m.
New subject: Searching for audio interface with software-controlled mic gain
i think the idea of modding a regular soundcard to have remote
controllable gain potentiometers is less "Heath-Robinson" than one might
think.
get some digital potentiometer like this
https://www.sparkfun.com/products/10613
to replace a soundcards gain pots and then hook it up (i.e. using this
https://www.sparkfun.com/products/12633) to a cheap USB OTG android
phone (i.e. ZTE Blade L3 - 80$) to provide wireless connectivity.
Am 04.09.15 um 11:17 schrieb Will Godfrey:
On Fri, 4 Sep 2015 10:38:54 +0200
Thomas Janu <thomas.janu(a)gmail.com> wrote:
Hi Lorenzo,
On Fri, Sep 4, 2015 at 10:00 AM, Lorenzo Sutton <lorenzofsutton(a)gmail.com>
wrote:
How about a Heath-Robinson solution?
Hook up an Arduino-mini (or the like) to voltage or digitally controlled
amplifiers and link it into the computer via USB. If that's not possible run an
external RS232 serial line to it.
Hi Thomas,
Sorry to dig up this oldish discussion and if I missed some of the ideas..
but it's actually quite interesting.
No problem - it's still not solved on our side, as the two solutions so far
were deemed too expensive for a test setup by my higher-ups. 
12:15 p.m.
New subject: Searching for audio interface with software-controlled mic gain
On Fri, 4 Sep 2015 10:17:38 +0100, Will Godfrey wrote:
On Fri, 4 Sep 2015 10:38:54 +0200
Thomas Janu <thomas.janu(a)gmail.com> wrote:
I was just thinking along similar lines. Particularly the Cypress PSoC 5LP.
It has Delta-sigma ADC on board for which "nominal operation is 16 bits at
48 ksps". It also has Programmable Gain Amplifiers for which "the gain is
adjustable at runtime, including changing the gain of the PGA prior to each
ADC sample". And there's a "24-bit fixed-point digital filter
processor".
All on a neat little board with a snap off USB programmer and mini USB at
the other end for $10. Programming it is fairly straightforward thanks to
the free PSoC creator software, but that doesn't run on Linux unfortunately.
http://www.cypress.com/documentation/development-kitsboards/cy8ckit-059-pso…
--
John.
Hi Lorenzo,
On Fri, Sep 4, 2015 at 10:00 AM, Lorenzo Sutton <lorenzofsutton(a)gmail.com>
wrote:
How about a Heath-Robinson solution?
Hook up an Arduino-mini (or the like) to voltage or digitally controlled
amplifiers and link it into the computer via USB. If that's not possible run an
external RS232 serial line to it.
Hi Thomas,
Sorry to dig up this oldish discussion and if I missed some of the ideas..
but it's actually quite interesting.
No problem - it's still not solved on our side, as the two solutions so far
were deemed too expensive for a test setup by my higher-ups.
11:54 a.m.
New subject: Searching for audio interface with software-controlled mic gain
On 04/09/2015 10:38, Thomas Janu wrote:
Hi Lorenzo,
On Fri, Sep 4, 2015 at 10:00 AM, Lorenzo Sutton
<lorenzofsutton(a)gmail.com <mailto:lorenzofsutton@gmail.com>> wrote:
[..]
No problem - it's still not solved on our side, as the two solutions so
far were deemed too expensive for a test setup by my higher-ups.
On 25/08/2015 09:23, Thomas Janu wrote:
[...]
The whole setup will be mounted at a remote location inside a larger
machinery for audio surveillance of said machinery (fault detection
etc.). The larger machinery of course may not be running while
opened to
install our setup, thus setting the gain has to be done remotely.
The PC in this setup has an x86_64 CPU running Ubuntu 12.04 LTS,
but the
case is too small for PCI(e) solutions, doesn't have firewire,
so the
only option is USB.
Does the audio interface *have* to be inside the machine as well?
What I mean is Couldn't you just have the mics in the machine and
the audio interface outside (and accessible) so as to possible set
the gain, fine tune, turn on/off etc.?
Sadly, it has to be inside. The bigger machine it's to be mounted in is
itself stationary and outside, and not exactly at ground level. There's
sadly no feasible way to have our stuff outside of the enclosure. If it
were, the cables would be on the order of ~100m and the stuff outside
the machinery would need to be secured against weather and - more
importantly - humans that have nothing to do with it, as it would be
publicly accessible.
As there is a climb involved, repeatedly turning the machine on,
checking the levels, turning the machine off, climbing up, adjusting the
levels, climbing down, turning the machine on, ... is also not feasible.
Well this clears a few points..
Interesting scenario... What is the importance of the microphones (and
their quality) in the chain?
Which relates to another more general question.. what kind of audio
analysis are you doing and what audio features are you measuring? e.g.
are you monitoring very subtle differences in amplitude? spectrum etc.?
Are you monitoring discreet audio events (e.g. a 'beep')...?
You do talk about a test scenario so I'm guessing budget constraints.
Probably you have already done all this analysis but it would be helpful
to set the gear requirements (and I'm curious about it now :-)
Lorenzo.
3373
days inactive
3383
days old
linux-audio-user@lists.linuxaudio.org
19 comments
10 participants
participants (10)
-
Felix Homann -
Jeremy Jongepier -
John Murphy -
laulau -
Len Ovens -
Lorenzo Sutton -
Peter P. -
Ralf Mardorf -
Thomas Janu -
Will Godfrey