[Ardour-Users] opening 3 channel file on a 4 channel track

Jörn Nettingsmeier nettings at stackingdwarves.net
Mon Oct 12 09:54:37 PDT 2009


e deleflie wrote:
> Hi Jörn,
> 
>> hmm. if you mix 3h1p, your panner will determine the channel order.
>> it doesn't make much sense to use a 16ch master bus in that case - you
>> will be shuffling a large number of zeros around for no reason. make
>> your master bus 9 channels, and add the silent channels when you export.
> 
> The thing is that I already have all the material (generated using
> Supercollider))... so I wont be doing any panning. All I want to do is
> mix 3rd order periphonic and horizontal only.
>
> I can write a script that copies the periphonic files and deletes any
> non-horizontal channels. I guess that's probably the easiest.

you know that you can always manually connect (or not connect) the
output channels of any track? i don't really see the problem.

so if you use a peri master bus, connect your horizontal-only tracks by
hand, skipping the channels you don't use. if you use a horizontal-only
master bus, connect your peri tracks by hand, omitting the channels that
don't affect the horizontal plane. you can create "route templates" for
this, so that you don't have to do the wiring by hand each time.

> Actually, Ardour is really not that far away from being able to do
> that. All it needs is to implement a switch to turn off spreading 1
> channel into the other empty ones ... and it is practically there.

that spreading is something that must be revisited (as in, thrown away)
anyway, imho.

>> if you have the resources to move all those zeroes, you might just as
>> well produce in 3rd order peri and downgrade when you master... so you
>> can later benefit from the superior h/v mixed order scheme once suitable
>> players are available.
> 
> yes I agree. To my mind all synthetic material should be produced to
> one agreed order. I'd say 3rd periphonic is ideal.

hmm. i don't see why. as soon as i have access to larger rigs and my
machine can handle it, i *will* go to fourth order or higher. why should
  people have to agree on an order?
for the forseeable future, first-order WXYZ with W at -3db is perfect as
a consumer format. any joe user that is capable of reproducing higher
orders will have a rig that can deal with arbitrary channel mappings and
normalisations.
as a convenient HOA interchange format, i'd be totally happy with
ACN/(S)N3D in any container that supports sparse data (i.e. handles
empty channels without significant storage or processing overhead, for
mixed order content).
i totally do not buy into endless lists of "this number of channels
means that..., except when...", and i don't care for backwards
compatibility. olden-style FuMa and a new standard can always peacefully
co-exist. but i don't want to have to explain to my grandchildren why
the normalisation doesn't make sense and the z-axis rotation-invariant
component keeps jumping around randomly from one order to the next.

(btw, i gues this is somewhat off-topic for ardour-users - if you wish
to discuss it further, feel free to take it over to sursound.)

best,

jörn


-- 
Jörn Nettingsmeier

Meister für Veranstaltungstechnik

Audio and event engineer
Ambisonic surround recordings

http://stackingdwarves.net
+49 177 7937487





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