Operating problem with Ndef


I have a buffer containing a stereo sound file:

~gerbaud = Buffer.read(s, "~/XavMusique/Supercollider/chanson/GerbaudAvec/desOiseaux_Gerbaud.aiff".standardizePath);

I create an Ndef to play this sound:

Ndef(\a, {PlayBuf.ar(2, ~gerbaud)}).play;

But I get this error message:

Ndef('a'): wrapped channels from 2 to 1 channels
Ndef('a'): adopted proxy input to control rate
WARNING: Can't monitor a control rate bus.
-> Ndef('a')



I changed the name of Ndef (\ b rather than \ a) and it works !!