Optical out works not as expected

I finally got the mini Toslink adapter to use my 5.1 speakers with the new iMac.

The wierd thing is that the output seems to not be always on - when no audio is played, the reciever displays on the screen that no Optical data is recived. When an OS alert sounds, for example, a thump is heard from the speakers and there is a very short delay and then the end of the sound plays.

Once any sound plays, it displays it as 2ch, 96. When DVDs are played (I have set it to forward to optical out) I get full 5.1 sound then and the screen reads Dolby Digital, perfect.

Normal?

That delay thing is always the case with Optical sound. Even when I switched from Coax to Optical for my Z5500, I got that same delay thing. Cause there is no optical data transmitted while there is no output.

As for upmixing that audio to 5.1, I hope there is such a tool for the Mac. Cause I'm dumping my PC to get one. Doesn't your receiver have a 5.1 upmix built in?

I have the Logitech Z5500 Digital. The LCD on the digital module reads "no optical data" and as soon as sound plays it reads whatever effect is set.

The strange thing is that when I disconnect the optical cable from the digital module the cable is not lit. If I play a sound with the optical cable disconnected, the cable remains lit even when the sound stops playing.

The Z5500 have built in 5.1 encoding and I can upmix the stereo output in Dolby Pro Logic music or movie.

The Z5500 rules doesn't it! Anyway, I'm currently using the same thing on an Auzentech Xplosion soundcard via Optical and it gives that same delay problem. Annoying to say the least.

Not tried the disconnecting thing though.