24 Mar
2020
24 Mar
'20
3:28 a.m.
Hi!
I tried to configure an Ardour session to make a simple ambisonics environment with just 4
speakers - FL, FR, RL, RR.
Following instructions from https://community.ardour.org/ambisonics, I added one mono
track, bypassed the builtin panners and took (I think it was) "AMB 1.1 mono
panner" (couldn't find "1h1v"), added 2 additional channels in
"Master" to get 4 of them and let my mono channel take the "Master" as
an output.
Then I started ambdec and tried to make some sane connections, but the inputs are not
called "w", "x" and "y", but only "0",
"1", "2", and so on
"man ambdec" didn't help.
/usr/share/doc/ambdec didn't help.
An old manual (for ambdec 0.4.2 - I use 0.7.1, or so) from Fons' kokkinizita-page at
linuxaudio.org didn't help.
So, I hope anyone at the linux audio user mailing list can jump in
Greets!
Mitsch
24 Mar
24 Mar
9:04 a.m.
Mar 24 2020, Mitsch has written:
Hi!
I tried to configure an Ardour session to make a simple ambisonics environment with just
4 speakers - FL, FR, RL, RR.
A constellation of four speakers, like yours, is called
quadrophonic.
Yes, first oder ambisonics also has four channels, known as W, X, Y and
Z. But these don't mark speakers, they mark pressure (overall loudness)
and three directions.
And so what ambdec does is decode one of the ambisonic formats into a
particular speaker setup.
Following instructions from
https://community.ardour.org/ambisonics, I added one mono track, bypassed the builtin
panners and took (I think it was) "AMB 1.1 mono panner" (couldn't find
"1h1v"), added 2 additional channels in "Master" to get 4 of them and
let my mono channel take the "Master" as an output.
Again for clarity:
there is a LADSPA plugin - also by Fons - called "AMB
order 1,1 mono panner", which will do and is probably what you have
used? This should be part of your distributions amb-plugins package. It
will produce the proper W, X, Y and Z from a mono source.
Then I started ambdec and tried to make some sane connections, but the inputs are not
called "w", "x" and "y", but only "0",
"1", "2", and so on?
As far as I can see, that's OK. Connect
your four outputs to the first
four inputs of ambdec. I have tried it with a few presets and as far as
I can tell, it always shows all 16 inputs, which should be needed for
full 3rd order ambisonics.
...
I hope this helps.
Best wishes,
Jeanette
--
* Website: http://juliencoder.de - for summer is a state of sound
* Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
* SoundCloud: https://soundcloud.com/jeanette_c
* Twitter: https://twitter.com/jeanette_c_s
* Audiobombs: https://www.audiobombs.com/users/jeanette_c
* GitHub: https://github.com/jeanette-c
But tell me what happens when it stops? <3
(Britney Spears)
6:27 p.m.
Am 24.03.20 um 08:04 schrieb Jeanette C.:
Yes! That's the right name.
Yeah, I've tried that. Master 1,2,3,4 to ambdec 0,1,2,3 via "catia".
By the way, @Fons, if he is watching that thread: I can't understand,
why counting in an audio application starts at "0". And I can't
understand why it seems better not keeping the ambisonics' nomenclature
for an ambisonics application… There may be reasons for this - maybe 3rd
order ambisonics complicates things, here? Nevertheless: Is it possible
to name the inputs at least by a number AND the corresponding ambisonics
channel name? That would be great!
I made sure, that the outputs of ambdec are correctly connected, which
is easy to test with the internal test signal. But there are a few
things that let me think, I'm wrong with the inputs, here:
* If the "mono panner" is in a neutral position (Azimuth: 0, Elevation:
0), I would expect to get a signal from exactly in front of me. Instead
I get an output signal of LF and LB which is 20dB higher than RF and RB.
I can reach the signals position that corresponds to the one I expected
if I set Elevation to 90. But then, changing azimuth does nothing
(instead of - my expectation - circling around me while changing it).
* Elevation: The Ardour page says, if there's no vertical dimension, I
shouldn't connect "z" - if I do that, ambdec changes it's reaction to
the "mono panners" values - but still it's not very intuitive to work
with. Or to be more precise: It's even getting worse…
Conclusion: I'm sure, ambisonics is no rocket science, but the tools I'm
depending on getting ambisonics to work don't make it that easy…
Greets!
Mitsch
Mar 24 2020, Mitsch has written:
Yes, first oder ambisonics also has four channels, known as W, X, Y and
Z. But these don't mark speakers, they mark pressure (overall loudness)
and three directions.
It took a while, but I understand the basic mechanics of ambisonics, now
- at least, I hope so.
It's a bit sad, that there seems to be no "ambisonics for newbies" site
to make it a bit easier to dive into this… The "Using ambisonics with
Ardour"-page really helped a lot, although the plugins and input
descriptions do not match to what I was confronted with.
And so what ambdec does is decode one of the ambisonic
formats into a
particular speaker setup.
That's right - I just have to use a configuration in
ambdec that matched
my speaker setup. I expected a configuration called "quadrophonic", but
I found a "square". Maybe quadrophonic is already occupied by another
surround systems nomenclature… Well, I'm fine with a "square"…
I would have made my own configuration, but I couldn't find the button
"new" in the configuration dialog, which was described in the manual of
the 0.4.2 version I've found on Fons' page. Is that handy tool given up
in later versions or am I too dump to handle it right?
Following
instructions from https://community.ardour.org/ambisonics,
I added one mono track, bypassed the builtin panners and took (I
think it was) "AMB 1.1 mono panner" (couldn't find "1h1v"), added
2
additional channels in "Master" to get 4 of them and let my mono
channel take the "Master" as an output.
Again for clarity: there is a
LADSPA plugin - also by Fons - called "AMB
order 1,1 mono panner", which will do and is probably what you have
used? Then I started
ambdec and tried to make some sane connections, but
the inputs are not called "w", "x" and "y", but only
"0", "1", "2",
and so on?
As far as I can see, that's OK. Connect your four outputs to the
first
four inputs of ambdec. 
25 Mar
25 Mar
12:44 a.m.
Michael Jarosch <riotsound(a)riotmusic.de> writes:
Beware about channel order. I have just added two rear speakers
to my 2.4m^2 desk[1] and am now also playing with quadrophonics.
First thing I found was the -audio-channels=quad option of mpv. This
will automatically route 6ch audio to a quadrophonic setup. Pretty
neat.
This assumes the following channel order: fl-fr-bl-br.
However, the square preset from ambdec assumes fl-fr-br-bl.
I guess you can just edit that file to swap the two rear channels to
adapt to your channel order.
[1] I put together 3 IKEA Linnmon corner tables and 1 normal 120x60cm
table which gives me a 240x240cm workspace with a inner circle with
diameter 120cm to sit in.
Finally, all my computer/home studio related stuff is in one place,
and it doesn't feel crowded anymore.
And since this thing is a square, putting a monitor at
each corner was just the obvious thing to do. Three sides of the square
are dedicated to computer, turntables, and modular synth, respectively.
Each of which has its own stereo pair of speakers.
And when I feel like it, I can use the whole thing in quadrophonic mode.
Finished just a few days before quarantine, perfect timing. :-)
--
CYa,
⡍⠁⠗⠊⠕
And so what
ambdec does is decode one of the ambisonic formats into a
particular speaker setup.
That's right - I just have to use a configuration in
ambdec that matched
my speaker setup. I expected a configuration called "quadrophonic", but
I found a "square". 
3:26 a.m.
On 3/24/20 9:27 AM, Michael Jarosch wrote:
Yes! That's the right name.
Best would be to create a 4 channel session to begin with (so that the
master is already quad, all new tracks autoconnect, etc).
Make sure your mono track is actually sending all four output channels
to the master, and that they are actually connected to the master bus
(and in the right order 1 to 1, 2 to 2, etc).
That is the way it normally is... maybe you can try the above command
from a terminal to see what you see?
Am 24.03.20 um 08:04 schrieb Jeanette C.:
That is the one to use for your setup.
Mar 24 2020, Mitsch has written:
Yes, first oder ambisonics also has four channels, known as W, X, Y and
Z. But these don't mark speakers, they mark pressure (overall loudness)
and three directions.
It took a while, but I understand the basic mechanics of ambisonics, now
- at least, I hope so.
It's a bit sad, that there seems to be no "ambisonics for newbies" site
to make it a bit easier to dive into this… The "Using ambisonics with
Ardour"-page really helped a lot, although the plugins and input
descriptions do not match to what I was confronted with.
And so what ambdec does is decode one of the
ambisonic formats into a
particular speaker setup.
That's right - I just have to use a configuration in ambdec that matched
my speaker setup. I expected a configuration called "quadrophonic", but
I found a "square". Maybe quadrophonic is already occupied by another
surround systems nomenclature… Well, I'm fine with a "square"…
I would have made my own configuration, but I couldn't find the button
"new" in the configuration dialog, which was described in the manual of
the 0.4.2 version I've found on Fons' page. Is that handy tool given up
in later versions or am I too dump to handle it right?
Making your own decoder is, well, not so easy to begin with (not
impossible). Best to start with well known configurations and use the
presets that come with Ambdec.
Following instructions from
https://community.ardour.org/ambisonics,
I added one mono track, bypassed the builtin panners and took (I
think it was) "AMB 1.1 mono panner" (couldn't find "1h1v"), added
2
additional channels in "Master" to get 4 of them and let my mono
channel take the "Master" as an output.
Again for clarity: there is a LADSPA plugin - also by Fons - called "AMB
order 1,1 mono panner", which will do and is probably what you have
used? >> Then I started ambdec and tried to make some
sane connections, but
>> the inputs are not called "w", "x" and "y", but
only "0", "1", "2",
>> and so on?
Weird, in my machine this is what I see (ambdec 0.5.1):
$ jack_lsp|grep ambdec
ambdec:in.0w
ambdec:in.1y
ambdec:in.1z
ambdec:in.1x
ambdec:in.2v
ambdec:in.2t
ambdec:in.2r
ambdec:in.2s
ambdec:in.2u
ambdec:in.3q
ambdec:in.3o
ambdec:in.3m
ambdec:in.3k
ambdec:in.3l
ambdec:in.3n
ambdec:in.3p
ambdec:test
the "0" is for the zeroeth order component (w), the "1"s for first
order, etc. What are you using to connect the jack ports?
As far as I
can see, that's OK. Connect your four outputs to the first
four inputs of ambdec.
Yeah, I've tried that. Master 1,2,3,4 to ambdec 0,1,2,3 via "catia".
By the way, @Fons, if he is watching that thread: I can't understand,
why counting in an audio application starts at "0". And I can't
understand why it seems better not keeping the ambisonics' nomenclature
for an ambisonics application… There may be reasons for this - maybe 3rd
order ambisonics complicates things, here? Nevertheless: Is it possible
to name the inputs at least by a number AND the corresponding ambisonics
channel name? That would be great! I made sure, that the outputs of ambdec are correctly
connected, which
is easy to test with the internal test signal. But there are a few
things that let me think, I'm wrong with the inputs, here:
* If the "mono panner" is in a neutral position (Azimuth: 0, Elevation:
0), I would expect to get a signal from exactly in front of me.
Correct,
Instead
I get an output signal of LF and LB which is 20dB higher than RF and RB.
(BTW, in all orders, but specially in first order you will not get
"silence" coming from any speakers, all speakers will contribute to the
soundfield.)
So it would seem that front is left, right (no pun intended)? Which
would mean you have Y (left-right) connected to the X (front-back)
decoder input.
I can reach the signals position that corresponds to
the one I expected
if I set Elevation to 90. But then, changing azimuth does nothing
(instead of - my expectation - circling around me while changing it).
That would seem to suggest that either the connections from Ardour to
Ambdec (most likely), or the connections from Ambdec to the speakers are
not right.
* Elevation: The Ardour page says, if there's no
vertical dimension, I
shouldn't connect "z" - if I do that, ambdec changes it's reaction to
the "mono panners" values - but still it's not very intuitive to work
with. Or to be more precise: It's even getting worse…
So Z is connected to either X or Y. And who knows where W is connected
to :-)
There has to be some confusion of what is connected to what. What you
hear would suggest that the order of the components coming into the
decoder is wrong (or maybe not all of them are connected).
Sorry you are having problems...
-- Fernando
Conclusion: I'm sure, ambisonics is no rocket
science, but the tools I'm
depending on getting ambisonics to work don't make it that easy…
10:59 a.m.
Am 25.03.20 um 02:26 schrieb Fernando Lopez-Lezcano:
Weird, in my machine this is what I see (ambdec 0.5.1):
$ jack_lsp|grep ambdec
ambdec:in.0w
ambdec:in.1y
ambdec:in.1z
ambdec:in.1x
ambdec:in.2v
ambdec:in.2t
ambdec:in.2r
ambdec:in.2s
ambdec:in.2u
ambdec:in.3q
ambdec:in.3o
ambdec:in.3m
ambdec:in.3k
ambdec:in.3l
ambdec:in.3n
ambdec:in.3p
ambdec:test
Yeah! That's the table I was looking for!
The "Using Ardour with Ambisonics"-page decodes the "mono panners"
outputs that way:
"Connect Ardour's master out as follows:
* out1 -> ambdec:in0_w
* out2 -> ambdec:in0_x
* out3 -> ambdec:in0_y"
>> As far as I can see, that's OK. Connect your four outputs to the first
>> four inputs of ambdec.
>
> Yeah, I've tried that. Master 1,2,3,4 to ambdec 0,1,2,3 via "catia".
So, if I can believe this data, I have connected "w" correctly, but made
"x" to "y", "y" to "z" and "z" to
"x".
I'm going to check that later…
Many thanks!
And Greets!
Mitsch
2:07 p.m.
Hi Fernando & all
Weird, in my machine this is what I see (ambdec
0.5.1):
$ jack_lsp|grep ambdec
ambdec:in.0w
ambdec:in.1y
ambdec:in.1z
ambdec:in.1x
ambdec:in.2v
ambdec:in.2t
ambdec:in.2r
ambdec:in.2s
ambdec:in.2u
ambdec:in.3q
ambdec:in.3o
ambdec:in.3m
ambdec:in.3k
ambdec:in.3l
ambdec:in.3n
ambdec:in.3p
ambdec:test
Current version is 0.7.1 (since Aug. 2018 IIRC :-).
It uses only the the ACN based names (there are good
reasons for that).
If you use the first order panners from AMB-plugins-0.8.1
the connections from Ardour to Ambdec shoul be
Ardour master Ambdec
-------------------------
1 in.0 (W)
2 in.3 (X)
3 in.1 (Y)
4 in.2 (Z)
Ciao,
--
FA
26 Mar
26 Mar
10:33 a.m.
Hi, there!
Thanks for the fast and detailed support to all of you. Can't wait to
check your input! If I'm stuck, again, 'll be back! :)
Greets!
Mitsch
Am 25.03.20 um 13:07 schrieb Fons Adriaensen:
Weird, in my
machine this is what I see (ambdec 0.5.1):
$ jack_lsp|grep ambdec
ambdec:in.0w
ambdec:in.1y
ambdec:in.1z
ambdec:in.1x
ambdec:in.2v
ambdec:in.2t
ambdec:in.2r
ambdec:in.2s
ambdec:in.2u
ambdec:in.3q
ambdec:in.3o
ambdec:in.3m
ambdec:in.3k
ambdec:in.3l
ambdec:in.3n
ambdec:in.3p
ambdec:test
Current version is 0.7.1 (since Aug. 2018 IIRC :-).
It uses only the the ACN based names (there are good
reasons for that).
If you use the first order panners from AMB-plugins-0.8.1
the connections from Ardour to Ambdec shoul be
Ardour master Ambdec
-------------------------
1 in.0 (W)
2 in.3 (X)
3 in.1 (Y)
4 in.2 (Z)
11:38 p.m.
On Thu, Mar 26, 2020 at 09:33:05AM +0100, Michael Jarosch wrote:
Thanks for the fast and detailed support to all of
you. Can't wait to
check your input! If I'm stuck, again, 'll be back! :)
In the meantime, I should advise everybody using the AMB plugins
to switch to the new ones released yesterday. Simplifies things,
and future-proof. Make sure to read the README.
Ciao,
--
FA
27 Mar
27 Mar
10:32 a.m.
Am 26.03.20 um 22:38 schrieb Fons Adriaensen:
In the meantime, I should advise everybody using the
AMB plugins
to switch to the new ones released yesterday. Simplifies things,
and future-proof.
As a Debian-testing-user, I prefer taking the stuff that my distribution
offers. The packages are not so out-dated as using stable but it always
depends on the maintainers for the particular package, how fast it will
be updated, you know…
Talking about "everybody": Do you also mean the "Debian multimedia
maintainers" which are responsible for amb-plugins? They will not be
informed by their "watch" mechanism, because the name of the plugins
changed…
Make sure to read the README.
I did and found a mistake:
"AMB1-plugins is a collection of LADSPA plugins for third order Ambisonics."
It's first order ambisonics, isn't it?
Greets! And thanks!
Mitsch
10:42 a.m.
On Fri, Mar 27, 2020 at 09:31:50AM +0100, Michael Jarosch wrote:
Indeed ! That's what happens with quick copy/past....
Ciao,
--
FA
Make sure to
read the README.
I did and found a mistake:
"AMB1-plugins is a collection of LADSPA plugins for third order Ambisonics."
It's first order ambisonics, isn't it?
25 Mar
25 Mar
1:15 p.m.
On Tue, Mar 24, 2020 at 05:27:16PM +0100, Michael Jarosch wrote:
Am 24.03.20 um 08:04 schrieb Jeanette C.:
Yes! That's the right name.
Yeah, I've tried that. Master 1,2,3,4 to ambdec 0,1,2,3 via "catia".
By the way, @Fons, if he is watching that thread: I can't understand,
why counting in an audio application starts at "0". And I can't
understand why it seems better not keeping the ambisonics' nomenclature
for an ambisonics application… There may be reasons for this - maybe 3rd
order ambisonics complicates things, here? Nevertheless: Is it possible
to name the inputs at least by a number AND the corresponding ambisonics
channel name? That would be great!
I made sure, that the outputs of ambdec are correctly connected, which
is easy to test with the internal test signal. But there are a few
things that let me think, I'm wrong with the inputs, here:
* If the "mono panner" is in a neutral position (Azimuth: 0, Elevation:
0), I would expect to get a signal from exactly in front of me. Instead
I get an output signal of LF and LB which is 20dB higher than RF and RB.
I can reach the signals position that corresponds to the one I expected
if I set Elevation to 90. But then, changing azimuth does nothing
(instead of - my expectation - circling around me while changing it).
* Elevation: The Ardour page says, if there's no vertical dimension, I
shouldn't connect "z" - if I do that, ambdec changes it's reaction to
the "mono panners" values - but still it's not very intuitive to work
with. Or to be more precise: It's even getting worse…
Conclusion: I'm sure, ambisonics is no rocket science, but the tools I'm
depending on getting ambisonics to work don't make it that easy…
Greets!
Mitsch
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
https://lists.linuxaudio.org/listinfo/linux-audio-user
Mar 24 2020, Mitsch has written:
Yes, first oder ambisonics also has four channels, known as W, X, Y and
Z. But these don't mark speakers, they mark pressure (overall loudness)
and three directions.
It took a while, but I understand the basic mechanics of ambisonics, now
- at least, I hope so.
It's a bit sad, that there seems to be no "ambisonics for newbies" site
to make it a bit easier to dive into this… The "Using ambisonics with
Ardour"-page really helped a lot, although the plugins and input
descriptions do not match to what I was confronted with.
And so what ambdec does is decode one of the
ambisonic formats into a
particular speaker setup.
That's right - I just have to use a configuration in
ambdec that matched
my speaker setup. I expected a configuration called "quadrophonic", but
I found a "square". Maybe quadrophonic is already occupied by another
surround systems nomenclature… Well, I'm fine with a "square"…
I would have made my own configuration, but I couldn't find the button
"new" in the configuration dialog, which was described in the manual of
the 0.4.2 version I've found on Fons' page. Is that handy tool given up
in later versions or am I too dump to handle it right?
Following
instructions from https://community.ardour.org/ambisonics,
I added one mono track, bypassed the builtin panners and took (I
think it was) "AMB 1.1 mono panner" (couldn't find "1h1v"), added
2
additional channels in "Master" to get 4 of them and let my mono
channel take the "Master" as an output.
Again for clarity: there is a
LADSPA plugin - also by Fons - called "AMB
order 1,1 mono panner", which will do and is probably what you have
used? Then I
started ambdec and tried to make some sane connections, but
the inputs are not called "w", "x" and "y", but only
"0", "1", "2",
and so on?
As far as I can see, that's OK. Connect your four outputs to the
first
four inputs of ambdec.
1:44 p.m.
On Tue, Mar 24, 2020 at 05:27:16PM +0100, Michael Jarosch wrote:
I would have made my own configuration, but I
couldn't find the button
"new" in the configuration dialog, which was described in the manual of
the 0.4.2 version I've found on Fons' page. Is that handy tool given up
in later versions or am I too dump to handle it right?
The manual is indeed out of date. The new option was dropped because
manually entering a preset wasn't very useful in the first place.
Ambdec preset are just text files, so all you need is a text editor,
but normally they would be machine-generated.
By the way, @Fons, if he is watching that thread: I
can't understand,
why counting in an audio application starts at "0". And I can't
understand why it seems better not keeping the ambisonics' nomenclature
for an ambisonics application… There may be reasons for this - maybe 3rd
order ambisonics complicates things, here? Nevertheless: Is it possible
to name the inputs at least by a number AND the corresponding ambisonics
channel name? That would be great!
All current (that is, since AMB was picked up by the surround video world)
AMB software uses the 'Ambix' standard. The main reason for this is that
the original conventions (knows as Furse-Malham) don't scale well to higher
orders. In the Ambix standard, channels names are based on the Ambisonic
Channel Number (ACN) which is defined mathematically, and this is turn
means that starting from zero is the 'natural' thing to do.
I made sure, that the outputs of ambdec are correctly
connected, which
is easy to test with the internal test signal. But there are a few
things that let me think, I'm wrong with the inputs, here:
* If the "mono panner" is in a neutral position (Azimuth: 0, Elevation:
0), I would expect to get a signal from exactly in front of me. Instead
I get an output signal of LF and LB which is 20dB higher than RF and RB.
That looks normal. Ambisonics doesn't work by using only the nearest
speakers - even if you pan a sound in the actual direction of a speaker
the others will not be silent. This is very apparent in low order AMB,
less so for higher orders.
I can reach the signals position that corresponds to
the one I expected
if I set Elevation to 90. But then, changing azimuth does nothing
(instead of - my expectation - circling around me while changing it).
Elevation +90 means 'above your head'. Azimuth doesn't matter here -
in the same way as longitude is undefined when you are at the North
Pole.
* Elevation: The Ardour page says, if there's no
vertical dimension, I
shouldn't connect "z" - if I do that, ambdec changes it's reaction to
the "mono panners" values - but still it's not very intuitive to work
with. Or to be more precise: It's even getting worse…
If the decoder expects Z (ACN 2), then it should be connected.
The square decoder doesn't expect or use Z, it shouldn't matter
if it is connected or not (assuming the other connections are
correct).
Conclusion: I'm sure, ambisonics is no rocket
science, but the tools I'm
depending on getting ambisonics to work don't make it that easy…
There is a lot of info on AMB on the web which is just plain wrong.
And the FuMa to Ambix conversion of course adds to the confusion.
I should really retire the original AMB plugins set, and replace
it by and Ambix compliant one. Now that I'm more less in 'house
arrest' that may happen soon (I've been using a 3rd order Ambix
set for years, it just was never released).
Ciao,
--
FA
1634
days inactive
1637
days old
linux-audio-user@lists.linuxaudio.org
12 comments
6 participants
participants (6)
-
Fernando Lopez-Lezcano -
Fons Adriaensen -
Jeanette C. -
Mario Lang -
Michael Jarosch -
Mitsch