2.1 sound from 2 channel SACDs

[jconde]

I have a Sony DVPns715 connected to a Yamaha receiver. I have been purchasing some of the Rolling Stones remastered CDs. However, I am spending more time listening to the regular redbook layer rather than the SACD layer because it uses my subwoofer. Is there any piece of equipment (reasonably priced that I can add to the system to do bass management or am I better off buying a new DVD player with bass management built in?

Thanks

 

[Cai Campbell]

Do you listen to CDs and SACDs on your DVPns755? If you do listen to CDs on this player, is it through the analog out or digital out?

The subwoofer has nothing to do with SACD stereo. This is an equipment/configuration issue. It would appear your receiver is deriving a subwoofer channel when employing the two-channel analog input you are using. This should be configurable on your receiver.

 

[ssully]

I wouldnt' say the subwoofer has nothing to do with SACD stereo. Assuming the Sony operates like other 'hirez' players, if the Sony's bass management is set for 'small' speakers and subwoofer ON, then bass from SACD stereo (or CD stereo) will be routed to the sub, *also assuming* the listener uses analog-out connections, not the digital out. Digital out will yield no output for SACD, and non-bass managed output for CD....in which case, for CD, the bass management would have to take place in the receiver.

IN a nutshell: jconde should use the 6-channel analog out connection, and set the Sony to do bass management for (at least) the front speakers. He should select the '6 channel' input on his receiver, when listening. Then he should hear bass managed stereo (2.1) , regardless of whether he plays the SACD or CD stereo layers.

 

[Cai Campbell]

I meant that the SACD stereo media does not contain an LFE channel. In other words, SACD stereo (like any other stereo media) is 2.0, not 2.1.

Any subwoofer from any stereo source is derived by the player and/or receiver and is not intrinsic to the media.

 

[ThomC]

I wouldnt' say the subwoofer has nothing to do with SACD stereo. Assuming the Sony operates like other 'hirez' players, if the Sony's bass management is set for 'small' speakers and subwoofer ON, then bass from SACD stereo (or CD stereo) will be routed to the sub, *also assuming* the listener uses analog-out connections, not the digital out. Digital out will yield no output for SACD, and non-bass managed output for CD....in which case, for CD, the bass management would have to take place in the receiver.

IN a nutshell: jconde should use the 6-channel analog out connection, and set the Sony to do bass management for (at least) the front speakers. He should select the '6 channel' input on his receiver, when listening. Then he should hear bass managed stereo (2.1) , regardless of whether he plays the SACD or CD stereo layers.

This is incorrect.
SACD/DSD has no bass management or other DSP as part of it's coding scheme.
The bass management must be done by the receiver's handling of analog inputs.
Bass management is only integrated into Dolby Digital & DTS streams.
Some players will also bass manage PCM audio with it's own DSP scheme.
The Sony players (and most of the better SACD players) do not convert the audio to PCM before conversion to analog, so no bass management.
You could get a cheaper player that converts DSD to PCM first, but that would kind of defeat the purpose, wouldn't it.

 

[jconde]

The DVPns715 does no bass management on its own for SACD. The speaker configuration menu works for DVDs but not for SACD. I have seen some DVD players that have an additional plug beyond the 5.1 plugs so that you can plug the .1 cable for bass management. I also heard that there is a separate bass management unit I can buy for a couple of hundred bucks. I was hoping to get the name of the device.

When I listen to the redbook layer. I use the digital output. The receiver then does the bass management. The result is a beautiful bass response. However, when I listen to the SACD layer, I have to use the analog output of the DVD player and no bass managemenbt takes place. Result: only the two front speakers get the signal.

 

[ssully]

Hold on there, pard. DSD was *invented* to be an archiving format for easy conversion to and from PCM, and mor ethan a few 'SACD's involve a PCM step in the mastering. No one has EVER demonstrated that such a conversion is necessarily audible (although it's possible to implement any technology poorly). THe audible benefits of bass managment , on the other hand, can be expected to far outweight any speculated audible 'degradation' -- a view currently being discussed and endorsed by some notable audio savants (e.g. Mssrs. Rubinson and Kotches) on avsforum.com. I'ts also a good discussion about 'signal purity' of SACD players in general
http://www.avsforum.com/avs-vb/showthread.php?s=&postid=3600743

From perusing the DVP-NS755V manual online (I presume this is a similar if not identical model to the NS755) it appears that Sony allows bass management of the front and center channels only, for SACD; however, the wording is ambiguous (the 'does not affect SACD' notice comes at the end of a footnote about tje the rear channel speaker size/location settings). Nor does it allow time alignment of SACD material (neither do many uniplayers).

Of course, if mr jcond's player *doesn't* allow BM of SACD at all, then he's SOL without an ICBM.

 

[jconde]

Of course, if mr jcond's player *doesn't* allow BM of SACD at all, then he's SOL without an ICBM.

Can you please tell what an ICBM is?

 

[ssully]

I'll do better, I'll direct you to the Outlaw Audio site
where you can find out all about the ICBM...which is an outboard unit for analog bass management.

Outlaw Audio

 

[jconde]

Is this device really worth the $250 they ask for it?

 

[bmoura]

This is incorrect.
SACD/DSD has no bass management or other DSP as part of it's coding scheme.
The bass management must be done by the receiver's handling of analog inputs.
Bass management is only integrated into Dolby Digital & DTS streams.
Some players will also bass manage PCM audio with it's own DSP scheme.
The Sony players (and most of the better SACD players) do not convert the audio to PCM before conversion to analog, so no bass management.
You could get a cheaper player that converts DSD to PCM first, but that would kind of defeat the purpose, wouldn't it.

Also worth noting that some SACD players do have a DSD-DSP chip that does some of these functions in the DSD domain.

 

[ThomC]

Also worth noting that some SACD players do have a DSD-DSP chip that does some of these functions in the DSD domain.

Really!!!
I was not aware of this.
Are these newer units?

 

[ssully]

Really!!!
I was not aware of this.
Are these newer units?

Seems controversial to me. From what I'm reading from some engineering types,
currently BM (but not time aligment) has to involve a PCM conversion.
See Andy Yew's post of 3/30/04 , currently near the end of this avsforum.com thread:


signal purity thread


Here's a Denon chart showing that BM (here called 'speaker configuration), but not time alignment, of SACD involves a PCM conversion step:

Denon DVD-5900 chart

I kind of hate posting this stuff, because it leads audio 'hypochondriacs' to think that
something *bad* must be going on, when in fact no one's demonstrated that a properly-done DSD-->PCM conversion is audible.

 

[bmoura]

Really!!!
I was not aware of this.
Are these newer units?

Yes. Some of the newer SACD players have DSD-DSP chips in them to do the bass management.

 

[High Fidelity Review]

Brian is right; DSD bass management has been around for some time, not just in the most recent machines. If manufacturers are converting signals to PCM, then it is by design rather than necessity.

At AES in 2002, HFR reporters set out to find an answer to the bass management question and went through many levels of Sony and Philips technical personnel to that end. A general sense of confusion is not surprising as not even Dr. Demery could cast any light on the matter, but we finally tracked down Muneyasu Maeda, who is Sony’s Senior SACD Generalist. He designed the format specifications for hybrid discs and oversaw the implementation of Sony’s bass management chip, which he could tell us performs bass management entirely within the DSD domain.

 

[ssully]

From what I'm reading over AVSforum.com, it may come down to technical semantics. Sony claims that the 'DSD domain' DSP (digital sound processing, such as BM) used in players like the flagship-level SCD-XA9000ES is modelled after DSD editing found in professional consoles. However, AIUI in such consoled such editing is done in '8-bit' DSD which is essentially a form of PCM. So the idea bruited about is that the Sony 'DSD' DSP chips are really doing a 1-bit->8-bit->1-bit switcherroo inside the chip to perform the BM calculations. Going in and coming out it would look like 1-bit DSD. One complication to this idea (which arises, AIUI, because there are inherent reasons why such calculation cannot be done in a 1-bit domain) is that Sony appears to claim in a white paper that their DSD DSP chip operates as 1-bit.
The techical folks at AVforum seem skeptical, since no such technology has been described to the AES or similar forums. As before, see this thread for the ongoing discussion:

signal purity

 

[bmoura]

Brian is right; DSD bass management has been around for some time, not just in the most recent machines. If manufacturers are converting signals to PCM, then it is by design rather than necessity.

At AES in 2002, HFR reporters set out to find an answer to the bass management question and went through many levels of Sony and Philips technical personnel to that end. A general sense of confusion is not surprising as not even Dr. Demery could cast any light on the matter, but we finally tracked down Muneyasu Maeda, who is Sony’s Senior SACD Generalist. He designed the format specifications for hybrid discs and oversaw the implementation of Sony’s bass management chip, which he could tell us performs bass management entirely within the DSD domain.

I'm not sure what the other SACD makers are doing, but Sony has been using a DSD-DSP chip for awhile now on some of their SACD players. Pretty much old news by now.