Re: Getting the spacial position of speakers?
Re: Getting the spacial position of speakers?
- Subject: Re: Getting the spacial position of speakers?
- From: Jean-Francois Roy <email@hidden>
- Date: Tue, 11 May 2004 18:40:12 -0400
Oh, I didn't mean the actual speakers, I meant the virtual ones, as
configured in AMS.
The angles are all good, but I would need distance as well. What I
would like to do is position my sources optimally so that the mixer
outputs as much of a given source through a given specific channel.
Come to think of it, distance should only influence the distance
dampening of the signal. What I want are fully directional sources.
Will setting an angle of 0 for inner and outer cone yield incorrect
results? I probably need some margin of error.
I also noticed that no mixing is done at all on sources with a stereo
buffer attached to them, but that's to be expected I suppose. Is the
recommended way of dealing with multi-channel input buffers to generate
n sources for an initial buffer of n channels and position the sources
accordingly? If I start playback on those sources at the same time
(using a single play command), can I expect not to have synchronization
issues (within a reasonable domain that is)?
On May 11, 2004, at 17:29, Bill Cooney wrote:
>
Unless you have GPS in each speaker, I doubt it. The best way would be
>
to map your sounds to the standard 5.1 sound field. There's diagrams
>
available, but basically the center is in front, the L + R channels
>
are 30 degrees either side of that and I think the rears are 55
>
degrees from center (i could be wrong about the rears). Ideally all
>
consumers would map their surround setups to the same standard, but
>
this is the one we use when setting up portable 5.1 for performances.
>
>
To gain access to the 'y' space for surround, you need either a
>
different standard of surround that uses extra speakers for height (i
>
think sony have one) or there's some interesting psychoacoustic stuff
>
you can do to sound to make it appear higher.
>
>
I should think that you could map the speaker layout to a grid (with
>
the listener at ground zero) and then place your sound within there
>
and then send the results to all 5 speakers.
>
>
Bill
>
>
On 12/05/2004, at 6:12 AM, Jean-Francois Roy wrote:
>
>
> Greetings,
>
>
>
> I am currently trying to write a very simple sound engine using
>
> Apple's
>
> new OpenAL implementation, and I was wondering something about speaker
>
> position (in a multi-channel environment).
>
>
>
> As you all know, one can configure the position of speakers in
>
> "listener space" (only x and z axis from what I can tell) in Audio
>
> MIDI
>
> Setup. I was wondering if there was a way to get the actual
>
> coordinates
>
> of each speaker (given its channel number possibly) with respect to
>
> the
>
> listener (or the coordinate system, but theoretically the listener is
>
> at {0, 0, 0}) in order to place, for instance, a source directly "on"
>
> or "at" a speaker or channel.
>
>
>
> There doesn't seem to be any mention of that in the OAL specs, from
>
> what I understood of them in any case.
>
>
>
> Regards,
>
> Jeff Roy
>
>
>
> --
>
> Co-Founder of MacStorm
>
> Programmer at MacStorm
>
>
>
> http://www.macstorm.org
>
> email@hidden
>
>
>
> http://www.macstorm.org/bahamut/Jean-Francois.gpgkey
>
>
>
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>
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>
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--
>
Bill Cooney, B.Mus (Music Technology)
>
Original Music for Film, Television, Theatre and Multimedia
>
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Jeff Roy
--
Co-Founder of MacStorm
Programmer at MacStorm
http://www.macstorm.org
email@hidden
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