Originally Posted by tinkinHD
Are you sure the receiver doesn't know to ignore 2-channel mode and output 5.1 discreet channels when the source is Dolby or DTS? When I stream a movie in 5.1, and then switch between Multi-Stereo and AFD modes, the output sounds identical, and the receiver says DTS-MA or whatever regardless.
If the receiver overrode the sound mode you had selected simply because it detected a Dolby/DTS 5.1/7.1 soundtrack then it would limit your ability to adjust the audio to something else, should you prefer it. I haven't tested it with the STR DN1040 yet, but I know that with my old 5.1 channel Sony receiver, if you had Stereo selected then that was what the receiver put out, regardless of what you were feeding it. The DTS/Dolby indicator lights merely inform you that your receiver is receiving a DTS/Dolby soundtrack. It doesn't necessarily mean that what your AVR is putting out is the original 5.1/7.1 mix, with zero modification.
For example, some people prefer using front heights rather than rear surrounds. In this situation, even if you are playing a 7.1 channel soundtrack, you need to be able to switch the receiver's sound mode to Dolby PL IIz. Otherwise, the sounds that were meant for the rear surrounds would be directed to your front heights, which would not sound right. Also, if the soundtrack you are playing is only 5.1, but you want to use all 7.2 speakers you need to be able to use Dolby PL IIx or Dolby PL IIz to do so. While not a feature of the STR DN1040, there are 9.1 and even 11.1 channel receivers with the ability to expand a 2.0/5.1/7.1 soundtrack to use all available speakers using the DTS Neo:X surround processing mode. If your sound mode setting was simply ignored when the receiver detected a Dolby/DTS signal then it would not be possible to force your receiver to use all available speakers when the soundtrack has fewer discrete channels than you have speakers. This would make DTS Neo:X completely worthless since there aren't any 9.1 or 11.1 channel soundtracks available for home use at present.
Similarly, you can also use the sound mode setting to force a 5.1/7.1 soundtrack to be output as stereo, multi-stereo, or any of the other sound modes available on your receiver, regardless of the number of speakers you have attached.