Hi Gintas,
my case is not exactly the same as yours, but it's very similar for this "audio question": I own an avant with HDR2.
my tv cable provider send me 3 tv stations in "bi-canal" (english+french) and I always can switch between them in the avant by using the beo4 "SOUND" command.
I've recorded all those 3 "bi-canal" tv stations and the result is always the same: I can record ONLY ONE LANGUAGE each time with HDR2 in ALL the audio options in -> V tuner-setup-extra-tuning-sound (mono-1,mono-2, stereo, mono-3, stereo-2) with mono-1, stereo and mono3 the languaje-A, and with mono2 and stereo2 the languaje-B;
During the changing of those different audio modes in the v-tuner menu,
I can already listen the languaje selected, and this is the languaje
recorded afterwards.
But in ANY case I CANNOT record both languages at the same time!!!! even if I try reproduce your problem.
That's why I suspect that your problem is not with the HDR but with the audio signal received, maybe your tv provider (or your external tv decoder) is sending a wrong audio signal to your HDR1 (a "fake" bicanal, stereo-mixed), then your HDR cannot split correctly those audio channels.
The HDR2 user manual indicates that HDR2 cannot record a real bicanal broadcast (mono1+mono2), if you want two languages you must store the program twice, one for each languaje.
Good luck