Dolby / PCM / Coax question

jkkyler · 01-21-2008, 06:46 PM

Question is toward the end if you want to skip ahead

Since I ended up not getting a new AVR I thought I was getting I went over to my local BB to check out what 'high end Avr ' they might offer and instead came home with a Blu-Ray player that was on clearance. It was a Sammy and so is my TV (I refuse to buy Sony ) so no additional remote needed

. So now I can watch HD-DVD and Blu-Ray Discs and not spend my time scouring the globe for foreign releases on HD-DVD and the HDMI would give me an upconverting dvd player. But just as important is that as I try and find my new AVR I want to experience the new lossless audio formats since my receiver has 6ch input. I have my BRD player hooked up to my receiver by both digital coax and 6ch output to AVR. After hooking everything up when I listen to a disc (Spiderman 3 to be exact) using 6ch and Dolby TrueHD everything is great with one minor nuance. The subwoofer/lfe is way to low, confirmed with disc test tones in speaker setup in blu-ray player ( I assume it has to do with the LFE not being processed and 'boosted' properly since it is decoded in my BDP but not by my AVR - when it gets there it is no longer digital) but my level buttons are on my remote and by turning the level up on the sub from -4 to +5 it sounds right. By that I mean the volume and tones seem right but what my hearing notices the most is between uncompressed audio and lossy audio (more dolby5.1 than dts) is that in uncompressed the bass and low ranges seem more tight + sharp and less boomy or boxy. Also note some improved purity on certain bells and chimes.
My problem is with the digital coax I also have hooked up. When I have it set to bitstream my receiver handles it properly. But when I set up my BDP to PCM (settings are-PCM Downsampling = off , Dynamic Compression = Off) and I go to the movie menu and select 5.1 pcm sound and hit play, my AVR detects 2 channel stereo not 5.1, and if I switch the sound in the movie menu to dolby and leave it at PCM output my AVR detects it as 2 ch and goes into PLII mode. (1) Am I doing something wrong? (2) Can you not get PCM on digital coax only optical (I have always used optical in the past) also the digit coax is one that the D*tv guy had improperly hoooked up during my install (He ran rca composites from the hdbox to the tv then coax from the tv to the avr- go figure

)- (3)how is it different from a component cable or are they interchangeable?

BIslander · 01-22-2008, 12:51 AM

First, SPDIF digital (optical and coax) simply cannot carry multichannel PCM, only two channel. With SPDIF you can only get multichannel by bitstreaming DD or DTS to your receiver for decoding. So, no, you are not doing anything wrong. It's just the way SPDIF works (or doesn't work, as the case may be).

Second, does your receiver offer the option of a +10 or +15dB boost for the sub/LFE input from the analog inputs? LFE should arrive at the receiver -10dB in relation to the other channels in order to provide headroom for bass effects. Even though bass management is happening in the player, the receiver still needs to be able to boost the LFE input to get it back in balance with the other channels. If the player sent LFE at full volume, bass peaks would start clipping. So, it looks to me like the player is operating correctly and that you are correctly boosting LFE in the receiver for the multichannel analog inputs.

DaveJ · 01-24-2008, 07:53 PM

jk
A couple of quick thoughts. First, the BA sub has it's own volume control in the recess on the top. Have you messed with it (or someone else) by turning the volume down?
Second, BA does not list a LFE input for the XB2, only for the 4,6,8 models. Is this part of the problem?
dave

01-21-2008, 06:46 PM	#1
jkkyler High Definition is the definition of life. Join Date: Nov 2007 Location: Ohio Age: 40 Posts: 367	Dolby / PCM / Coax question Question is toward the end if you want to skip ahead Since I ended up not getting a new AVR I thought I was getting I went over to my local BB to check out what 'high end Avr ' they might offer and instead came home with a Blu-Ray player that was on clearance. It was a Sammy and so is my TV (I refuse to buy Sony ) so no additional remote needed . So now I can watch HD-DVD and Blu-Ray Discs and not spend my time scouring the globe for foreign releases on HD-DVD and the HDMI would give me an upconverting dvd player. But just as important is that as I try and find my new AVR I want to experience the new lossless audio formats since my receiver has 6ch input. I have my BRD player hooked up to my receiver by both digital coax and 6ch output to AVR. After hooking everything up when I listen to a disc (Spiderman 3 to be exact) using 6ch and Dolby TrueHD everything is great with one minor nuance. The subwoofer/lfe is way to low, confirmed with disc test tones in speaker setup in blu-ray player ( I assume it has to do with the LFE not being processed and 'boosted' properly since it is decoded in my BDP but not by my AVR - when it gets there it is no longer digital) but my level buttons are on my remote and by turning the level up on the sub from -4 to +5 it sounds right. By that I mean the volume and tones seem right but what my hearing notices the most is between uncompressed audio and lossy audio (more dolby5.1 than dts) is that in uncompressed the bass and low ranges seem more tight + sharp and less boomy or boxy. Also note some improved purity on certain bells and chimes. My problem is with the digital coax I also have hooked up. When I have it set to bitstream my receiver handles it properly. But when I set up my BDP to PCM (settings are-PCM Downsampling = off , Dynamic Compression = Off) and I go to the movie menu and select 5.1 pcm sound and hit play, my AVR detects 2 channel stereo not 5.1, and if I switch the sound in the movie menu to dolby and leave it at PCM output my AVR detects it as 2 ch and goes into PLII mode. (1) Am I doing something wrong? (2) Can you not get PCM on digital coax only optical (I have always used optical in the past) also the digit coax is one that the Dtv guy had improperly hoooked up during my install (He ran rca composites from the hdbox to the tv then coax from the tv to the avr- go figure )- (3)how is it different from a component cable or are they interchangeable? __________________ HT- Panasonic TH-50PZ800U 1080p plasma, Panasonic PT-AX200u LCD projector, Elite Vmax Electric 100' screen, Onkyo TX-NR905 AVR, Paradigm Titan Monitor v5 fronts, Paradigm CC-190 v6 center, Paradigm Atom Monitors v5 surrounds(x4), HSU research VTF-2 sub, xbox360+hd-dvd player ,Sony BDP-S550 blu-ray, Dtv H21 HD-DVR Bedroom: Insignia NS-lcd26, Samsung BDP-1400 blu-ray Whether you think you can, or think you can't - You're Right

01-24-2008, 07:53 PM	#3
DaveJ In HT, size matters Join Date: Dec 2007 Location: Alameda, an island in SF Bay Age: 61 Posts: 101	quick thought jk A couple of quick thoughts. First, the BA sub has it's own volume control in the recess on the top. Have you messed with it (or someone else) by turning the volume down? Second, BA does not list a LFE input for the XB2, only for the 4,6,8 models. Is this part of the problem? dave

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01-22-2008, 12:51 AM	#2
BIslander Member Join Date: Jan 2008 Location: Bainbridge Island, WA Posts: 573	First, SPDIF digital (optical and coax) simply cannot carry multichannel PCM, only two channel. With SPDIF you can only get multichannel by bitstreaming DD or DTS to your receiver for decoding. So, no, you are not doing anything wrong. It's just the way SPDIF works (or doesn't work, as the case may be). Second, does your receiver offer the option of a +10 or +15dB boost for the sub/LFE input from the analog inputs? LFE should arrive at the receiver -10dB in relation to the other channels in order to provide headroom for bass effects. Even though bass management is happening in the player, the receiver still needs to be able to boost the LFE input to get it back in balance with the other channels. If the player sent LFE at full volume, bass peaks would start clipping. So, it looks to me like the player is operating correctly and that you are correctly boosting LFE in the receiver for the multichannel analog inputs.