[mah]

hello, anything specific i need to do to my DVD player to use DTS or Dolby? I have a samsung 931, connected via component and optical to a yamaha 7.1 receiver.


I've heard there is a 'bitstream and pcm" setting? can someone elaborate?


Also, i have 7.1 setup. is it true during dolby 5.1 movies, the back speakers are rendered useless and the middle speakers take over?


thanks


mah

 

[BGLeduc]

Yes, you normally can choose between PCM or Bitstream for both DD and DTS. If your receiver can decode both, then set them both to bit stream. If it can not, set them to PCM.


That said, most any receiver purchase in the last 4 to 5 years should have both DD and DTS, so bitsream is the correct setting for both.


As for 5.1 vs. 7.1, DD is a discrete 5.1 channel format, as is DTS. However, both formats have a 6. 1 equivalent. DD has DD EX, where a 6th back channel is matrixed between the two rear channels. DTS has a matrixed format as well DTS ES, and a discrete 6.1 format DTS EX (IIRC).


Your rig should allow you to choose which formats to use. For normal DD/DTS, the two back surrounds would by off, but the side surrounds would be active. If you engage DD EX, or DTS ES/EX, then the rears should come on, but not at the expense of the side surrounds.


The only time that the sound would collapse to the rear backs would be for older soundtracks that were originally Pro Logic (which had mono surrounds). Newer soundtracks with discrete surrounds would play fine through all rear channels.


One more note: Some DD EX titles (Star Wars for example) are improperly flagged, and thus do not signal your receiver to activate the rear back channels. For those, you need to manually invoke DD EX.


This does not seem to be an issue with DTS ES/EX, which always seem to be properly flagged (at least with the titles I own).


BGL

 

[mah]

Thanks for the response. what is the main difference in pcm and bitstream as i know most dvd players are defaulted to pcm. i think i will switch my satellite receiver to bitstream as well.



also, on the dvd's, on 5.1 dd or dts, i can change them to dts or dolby enhanced on the receiver? so i can recreate the 6 channel sound? do you do this regularly for 5.1 stuff?


thanks


mah

 

[BGLeduc]

PCM is a two channel signal (derived from the 5.1 mix, or from a separate 2 CH mix) that your receiver will decode as stereo or Pro Logic, or DTS NEO:6.


Bitsream sends the raw DD or DTS track to the receiver where it is then decoded.


I normally stick with plain DD/DTS 5.1 for soundtracks that are not DD EX or DTS ES. However, if its a newer film, I have lately been engaging DD EX manually. In most cases, it does present a bit more envelopment across the back of the room.


BGL

 

[mah]

So as i've had mine on PCM for so long, do you notice a significant improvement in audio going to bitstream on the DVD player?


Do you use bitstream only for your satellite receiver as well?


interesting stuff. thanks

 

[BGLeduc]

Well, will potentially hear a HUGE improvement, particlularly in the bass. Plus, your surrounds will now be discrete, rather than mono, and there will be much better separation across the front three.


The reason is that, downmixing to PCM to produce a Pro Logic mix will discard the .1 channel. There could be a substantial amount of bass mixed into the .1 channel. (I am not sure what happens when a DTS mix is downmixed to PCM....).


While I tend to dismiss comments that say one format will "blow the other away", comparing proper DD to Pro Logic should do just that.


Again, assuming your receiver is Dolby Digital and/or DTS capable, you should choose bitstream for ALL sources that can do so; cable, sat, OTA digital TV, DVD....


BGL

 

[mah]

thanks, i changed my dvd to bitstream last nite and did notice a difference. clearer and more distinct separation of channels. although the pcm option still did provide discreet separation of audio on the different speakers. i assume bitstream is just more discreet and clearer.


thanks for the info. appreciate it.