adding a bluetooth headset to a Denon AVR-X1200W receiver

[Cl0udberry]

my brother has a Denon AVR-X1200W with a great 7.1 system, and he's trying to get a Bluetooth headset working for his wife (who's hard of hearing) while the main speakers are still on.
The problem is, the front headphone jack mutes the speakers, and his Zone 2 is already in use.

All of his sources are HDMI, so he can't just split an RCA signal. Is there any way to get a separate audio output from that receiver to feed a Bluetooth transmitter?
I want to help him, but I'm stumped.

 

[LightBeam]

Okay, so here's a tip, hook up the AVR's optical TOSLINK output to a Bluetooth transmitter. This way, your main speakers won't go silent, and it plays nice with HDMI sources too.

 

[AHepple]

I think you will need an HDMI audio splitter that pulls audio before it hits the Denon. That way you can send one line to the receiver and another to a Bluetooth transmitter. Is he okay adding a small box between the source and AVR?