I have been reading the manuals and I noticed that there is no audio
output on the brick (like there is on the portable)
The sound is generated autonomously by the display unit.
The documentation is sparse. I also could not find any info on an
audio output or sound spec of the display units.

This is relevant for people who intend to route the audio output
signal into their sound system, e.g. to their headphones (motor
gliders)
Also the bright red LED solution that Bumper wrote about (controlling
a LED with the audio signal) will not be possible with the brick.
3U