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3D bformat and speakers positioning

Spat
#1

Hello T.

There is something I don’t manage to set right with the spat.decoder~ object. I have eight speakers placed as a cube in my room, and I can’t get the spat.decoder~ to output the audio correctly when the sound is panned above or bellow. As I can’t explain clearly the problem, I attached a simple patch for verification.

As you can see in the patch it is 3D bformat (WXYZ), the speakers are properly declared (I think), but when I increase or decrease the elevation the wrong speakers are getting louder. So there no feeling of height. It seems quite simple but I can’t get it to work :confused: Can you explain what I’m doing wrong? Also, There is no problem when the decoder is set to hoa3d.

One more thing, it seems that the messages “listener pitch $1” and “listener roll $1” are broken in spat.pan~ & spat.spat~ on the latest release. version 4.7.5 was ok. It doesn’t work anymore on 4.7.6. Only “listener yaw $1” is working. I verified on several computers, and it just doesn’t work.

Sorry for this late message.
Philippe

3D-Bformat-speakers-positions.maxpat (7.14 KB)

#2

Hi Philippe,

Thanks for the feedback.
Indeed I recently noticed that the b-format decoder seems to be broken in the latest version(s?).
I’m fixing it immediately; a new release will follow soon.

Cheers,
T.

#3

Hi again,

As for the “listener” messages for ‘spat.pan~’ or ‘spat.spat~’, I don’t think that ‘pitch’ and ‘roll’ have ever been implemented.
Indeed you are not really supposed to use those kind of messages. If you want to move/rotate the listener position (in binaural), you should instead use ‘spat.abs2rel’ to convert coordinates and orientation in the listener’ coordinate system, prior to processing with ‘spat.pan~’ or ‘spat.spat~’.
I don’t know if that’s clear ?

T.