Trouble Running a Phanotm Center with Multichannel PCM Input

[skers_54]

I'm having some trouble getting my receiver (Marantz 4001) to run a phantom center when watching HD-DVDs and having my Toshiba A30 output the hi-res audio as decoded PCM. For some reason, I can't get my receiver to mix the center channel into the left and right channels. I get the left and right channels fine, but the center information (ie dialog) is missing unless I set the center to "Yes". I set my center to "None" on the receiver but I didn't find anything in either the setup menu or manual about downmixing a PCM input. It will run a phantom center fine when I play a DD or DTS track from a DVD. There aren't any settings on the player to let it know which speakers I'm using either. Does anyone have any ideas about a setting I'm missing? Is my receiver just incapable of downmixing a multichannel PCM input?

 

[j_garcia]

Settings in the player wouldn't make any difference as they would typically only affect the analog outs. I doubt there is a setting for this, it sounds like it is a problem and I have a feeling there won't be a simple fix for it.

 

[Adam]

From the reading that I've done this morning, I'm still not clear on if an LPCM signal can be processed at all - some say yes, some say no. Let's assume it can be for the moment. Your manual states that some DVD-Audio discs will disable downmixing. I wonder if that's also true for HD-DVDs.

Now, onto some potential fixes. Can you set the PCM output frequency on the Toshiba to 48 KHz instead of 96 KHz? Some of the wording in the 4001 manual makes me think that it can't process 96 KHz PCM other than in stereo.

Also, do you have an open optical input on the 4001? If nothing else, you could connect the optical output on the Toshiba to the 4001 and send the audio over as bitstream. You might find the end product to be better that way than sending a lossless codec over as PCM. Just a thought.

 

[skers_54]

I got the same impression about 96kHz PCM as well. There isn't an option to set the sampling frequency, and the downmix option on the player only outputs stereo. I have tried optical out and it seemed to work fine. Just no hi-res . Since my receiver is one of the first to do audio over HDMI, it makes since that its processing capabilities are somewhat limited compared to newer products. My inkling is that the HDMI input functions more like the multichannel analog inputs than the optical/coax digital inputs.

 

[Highbar]

If I understand everything correctly when you use PCM you are basically sending a signal just like analog. The audio is already broken down into it's separate channels so all the receiver has to do is amplify the incoming signal. The player is more than likely doing the bass management for the setup too, ie crossover frequency and what not? If that's true you probably aren't going to be able to get it to remix the center channel back in, it's not designed for that. Your best bet is to send the receiver a DD or DTS signal, Sorry no HD audio for you

Now I"m kind of curious whether or not my Denon will do it. Maybe I'll have to try later, but that would mean recalibrating everything when I was done and I"m not sure I want to go through that

 

[Adam]

...no HD audio for you...

Highbar, a.k.a. "The HD Audio Nazi."

EDIT: I'm curious now, too, if my system could handle it. Maybe I'll try that this afternoon.

 

[skers_54]

If I understand everything correctly when you use PCM you are basically sending a signal just like analog. The audio is already broken down into it's separate channels so all the receiver has to do is amplify the incoming signal. The player is more than likely doing the bass management for the setup too, ie crossover frequency and what not? If that's true you probably aren't going to be able to get it to remix the center channel back in, it's not designed for that. Your best bet is to send the receiver a DD or DTS signal, Sorry no HD audio for you

Now I"m kind of curious whether or not my Denon will do it. Maybe I'll have to try later, but that would mean recalibrating everything when I was done and I"m not sure I want to go through that

My player doesn't have any settings for bass management, so my receiver would be doing that if it was doing anything. I know it was level-matching, as it is capable of doing that for the analog inputs. My receiver was definitely doing bass management for cds and dvds, but I think, as Adam pointed out, that it couldn't handle the 96 kHz input from hi-def discs.

I could hook up an extra Polk bookshelf I have laying around and say to Highbar, but I'd rather run a phantom center and use DD and DTS. I think they still sound pretty darn good.

I'd really like to know if my receiver was bass-managing the PCM input. In some brief comparisons on U-571, I though there was a bit more bass using optical but I had attributed it to not being able to switch inputs and back up fast enough. Maybe this could explain why some people say that bitstreaming sounds better than PCM? I might give Marantz a call and see if their tech people can shed any light on the issue...

 

[Adam]

According to the chart in your manual (and this is going off of memory from this morning), it doesn't list the sub as being active for multichannel PCM input. That didn't make much sense to me, so I'd like to ask - is your sub producing sound when you use the multichannel PCM?

 

[Highbar]

Highbar, a.k.a. "The HD Audio Nazi."

EDIT: I'm curious now, too, if my system could handle it. Maybe I'll try that this afternoon.

I wasn't even thinking about that when I typed it but good call

 

[Highbar]

My player doesn't have any settings for bass management, so my receiver would be doing that if it was doing anything. I know it was level-matching, as it is capable of doing that for the analog inputs. My receiver was definitely doing bass management for cds and dvds, but I think, as Adam pointed out, that it couldn't handle the 96 kHz input from hi-def discs.

I could hook up an extra Polk bookshelf I have laying around and say to Highbar, but I'd rather run a phantom center and use DD and DTS. I think they still sound pretty darn good.

I'd really like to know if my receiver was bass-managing the PCM input. In some brief comparisons on U-571, I though there was a bit more bass using optical but I had attributed it to not being able to switch inputs and back up fast enough. Maybe this could explain why some people say that bitstreaming sounds better than PCM? I might give Marantz a call and see if their tech people can shed any light on the issue...

Don't get me wrong there's nothing wrong with DD and DTS. I still watch plenty of movies with them, just like the HD formats too. They sound a little clearer for me. If you're receiver doesn't have your sub active over PCM I have to ask to; is the sub even on when using PCM? If not that will change the sound dramatically.

And I have no problem with a phantom center, just prefer an actual center channel if it fits.

 

[skers_54]

According to the chart in your manual (and this is going off of memory from this morning), it doesn't list the sub as being active for multichannel PCM input. That didn't make much sense to me, so I'd like to ask - is your sub producing sound when you use the multichannel PCM?

My sub (DIY Kappa Perfect) is definitely rumbling the room when I use multichannel PCM. The LFE light is on in the little box that shows what channels are being input. I'm getting the LFE channel to the sub for sure, but I don't know where the lows from the other channels are going.

Don't get me wrong there's nothing wrong with DD and DTS. I still watch plenty of movies with them, just like the HD formats too. They sound a little clearer for me. If you're receiver doesn't have your sub active over PCM I have to ask to; is the sub even on when using PCM? If not that will change the sound dramatically.

And I have no problem with a phantom center, just prefer an actual center channel if it fits.

I know you were joking about the whole "no HD audio" thing. I picked up on the same thing Adam did and I guess the facetious humor in my reply didn't translate well over the internet . I agree with your observations about the HD codecs and would prefer to use a center too, but med school textbooks override another pair of 2030p's at the moment .

 

[Adam]

Well, I just tried sending Dolby TrueHD over PCM to my receiver (Pioneer VSX-23) from my blu-ray player (Panasonic DMP-BD60) and setting my center to "No," and it worked just fine. The center channel information was transferred over to the front mains. I only tried one movie, though, which was Eagle Eye (I mention that because it might be related to the PCM frequency).

 

[skers_54]

Well, I just tried sending Dolby TrueHD over PCM to my receiver (Pioneer VSX-23) from my blu-ray player (Panasonic DMP-BD60) and setting my center to "No," and it worked just fine. The center channel information was transferred over to the front mains. I only tried one movie, though, which was Eagle Eye (I mention that because it might be related to the PCM frequency).

Interesting. I bet your receiver can process 96 kHz signals then. I played around with my receiver last night and I could get dialog when I used the "Virtual Surround" and stereo listening modes but it sounds like crap and I lose the surrounds (respectively). Guess this is something that people looking into older HDMI receivers should watch out for if they plan on using a phantom center.