Player decoding or Receiver decoding, that is the question

[yipcheah]

Anybody out there who can enlighten me on my questions on the HD format decoding.
I have a Primare SP 21 with excellent sound output for DTS and DD1.5. However it do not have HDMI input for HD codec such as STD HD and Dolby Tru HD. I intend to get the Pana DMP BD 50 Bluray player which has on board decoding for most of the latest sound codec. However, would my sound performance be better if I would to let the player does the decoding and connect the analogue 5.1 PCM output signal to the reciever anaolgue input directly for all blu ray movies in HD codec. I heard that 5.1 PCM signal output is definitely a better than the normal DTS or DD 1.5 output in bitstream format. Whay say you.[/QUOTE]

[Stephan.klose]

I read a couple of articles about that subject.

I came to the conclusion that it actually depends on the quality of your Sound Decoder inside the player. If that one ain't that good it's better to have receiver decode it. Which is always the option I go with because then the Logo's are displayed correctly

[Stephan.klose]

Originally Posted by yipcheah

Anybody out there who can enlighten me on my questions on the HD format decoding.
I have a Primare SP 21 with excellent sound output for DTS and DD1.5. However it do not have HDMI input for HD codec such as STD HD and Dolby Tru HD. I intend to get the Pana DMP BD 50 Bluray player which has on board decoding for most of the latest sound codec. However, would my sound performance be better if I would to let the player does the decoding and connect the analogue 5.1 PCM output signal to the reciever anaolgue input directly for all blu ray movies in HD codec. I heard that 5.1 PCM signal output is definitely a better than the normal DTS or DD 1.5 output in bitstream format. Whay say you.

[/QUOTE]

If your player has analogue 5.1 input it should work out fine. The Panasonic has a darn good internal decoder

[mx2004]

I have done alot more reading since my last post on this thread - my interest is in getting a high quality analog 5.1 (well 5.0 technically as I don't use a subwoofer!) output of DD Plus, Dolby True HD and both the DTS-HD formats. (On a side note, are there any releases with DTS-HD High Resolution on them?) My understanding now is that the Panasonic DMP-BD50 will do this (I am gradually overcoming my prejudice at Panasonic as a 'video' brand, where I would normally be looking towards 'hi-fi' brands like Marantz or Denon.... a few years back a player such as this might as easily have had a Technics badge on the front!). I was originally set on the Pioneer BDP-LX70, but all this will do as I understand it is the DTS core, even over the analogue outputs (it will only bitstream DTS-HD MA - it can't even send it out as PCM over HDMI!)

Now, the Marantz/Denon might be a better proposition for out-and-out SQ, but at probably over 3 (maybe even 4) times the price of the Panasonic I'm not sure it's going to be worth it. The only thing that might stop me is if the Sony 550 when it reaches Region B comes in at a similar price to the Panasonic - the spec page says it does analog 7.1 and decodes all the HD codecs. I could look at a new receiver, but that would be at considerably more cost that the BD player, and even a PS3 is not that much cheaper than a BD50 (a false economy when you factor in the cost of an HDMI receiver, hopefully a THX Ultra 2 one).

Rambling again. Apologies. I keep going back over this and making it longer! I appreciate your patience if you have actually read this thing. Anyone got any other players to suggest?

[yipcheah]

If your player has analogue 5.1 input it should work out fine. The Panasonic has a darn good internal decoder[/QUOTE]

Thank for the reply.
Is it the Panasonic 50 you are talking about. I understand the Pana 30 do not decode internally to analogue signal. Will the sound from the 5.1 analogue input to my AV amp be lossless sound quality as HD format.

[DarchAmonNagar]

If i were to by the Sony DAV-IS50 hooked up to my PS3 would I get HD audio on my Blu-rays?

https://www.sonystyle.co.uk/SonyStyl...02BC29B74)/.do

[Bryan Bennett]

Ok, alot of this IS confusing. I've been trying to figure out how to set up my new system that should be ready to install in a month or so... or at least after I get the new Sony S550. So here's my question(s)...

I get the 1080P display (Samsung FP-T6374), the S550 and a receiver (possibly a Onkyo HT-SP908).

Now, does the HDMI carry the audio and video through the receiver the out to the display?
Would using the analog out of the BD player to the receiver be better?
What might be the best way to connect this all up?

Thanks all, It'll really help.

[mx2004]

Originally Posted by Bryan Bennett

Ok, alot of this IS confusing. I've been trying to figure out how to set up my new system that should be ready to install in a month or so... or at least after I get the new Sony S550. So here's my question(s)...

I get the 1080P display (Samsung FP-T6374), the S550 and a receiver (possibly a Onkyo HT-SP908).

Now, does the HDMI carry the audio and video through the receiver the out to the display?
Would using the analog out of the BD player to the receiver be better?
What might be the best way to connect this all up?

Thanks all, It'll really help.

That's exactly right - HDMI from player to receiver carries audio & video - HDMI from receiver to display carries video.

I think the consensus of opinion is that if you can use HDMI, you should. It keeps it all digital that bit longer, reduces the cable-clutter and will give you access to the receiver's bass management/delay times/EQ etc which will almost certainly be more sophisticated than those on the player (although I'm not familiar with Onkyo products). It's really just people who refuse to part with their non-HDMI kit (like me) who should be considering analogue outputs. That said, if you have a few analogue cables lying around and you can try the analogue connection at no cost I would give it a go out of curiosity.

[Bryan Bennett]

Originally Posted by mx2004

That's exactly right - HDMI from player to receiver carries audio & video - HDMI from receiver to display carries video.

I think the consensus of opinion is that if you can use HDMI, you should. It keeps it all digital that bit longer, reduces the cable-clutter and will give you access to the receiver's bass management/delay times/EQ etc which will almost certainly be more sophisticated than those on the player (although I'm not familiar with Onkyo products). It's really just people who refuse to part with their non-HDMI kit (like me) who should be considering analogue outputs. That said, if you have a few analogue cables lying around and you can try the analogue connection at no cost I would give it a go out of curiosity.

Awesome. Guess I wasn't too far off then. Thanks for the clarification.

[EWL5]

This question ranks right up there with "Which BD player should I get?" and "Can I hear the new lossless audio using my current receiver?" Unfortunately, the answer is not so clear cut given the different combinations of equipment in everyone's setup. If you had the option to choose either, which would you pick? I'm hoping to unmuddy that question with this post.

On a purely theoretical basis, the decoding done in the player should be identical to the decoding done in the AVR/prepro. This makes sense because both Dolby and DTS license hardware to perform at the same specifications. The legacy DTS sound I heard 5 years ago should sound the same in the newer receivers because the chips used are conforming to the same legacy spec (everything else being equal of course).

Having said that, why are there so many claims by users that decoding in the AVR/prepro sounds audibly better than when decoding in the player? Shouldn't they sound the same given the fact that decoding is just a simple unwrapping of PCM from the original codec? Yes and No and here's why:

Yes, decoding will sound the same
When the following conditions are met
1) The crossover in the BD player is the same as the one in the AVR/prepro
2) Delay/Level settings for each speaker channel approximate the settings arrived at when calibrating for the AVR/prepro
3) For analog out, it is possible for the LFE to be boosted by +15dB in the downstream amp whenever speaker settings in the BD player are set to SMALL.
4) Identical DAC's used b/w the BD player and the AVR/prepro
5) Even more of a non-issue when a player decodes and transmits the PCM via HDMI 1.1+ as the DAC's are used in the AVR/prepro when digital transmission is involved.

How often does the above "perfect storm" happen?

No, decoding will not sound the same
1) Most BD players have a fixed crossover (~100-150Hz). CE manufacturers arrive at this number based on the need to support the popular HTIB. AVR/prepro's on the other hand, allow a multitude of crossover settings to best match your situation. If I own decent bookshelves that go down to 60Hz or lower, you better believe I'd rather have the THX recommended 80Hz crossover over the fixed crossover in the player. Analog users are at the mercy of the fixed crossover (decoding to PCM is not affected).
2) Most decent AVR/prepro's come with automatic calibration functions that attempt to correct for errant frequencies, nulls, etc. (examples include Audyssey, MCACC, etc.). Whether you go with the calibration settings or not, there's far more flexibility for equalization, delays, etc. with the AVR/prepro vs the BD player.
3) Boosting of LFE is always appropriately handled when the AVR/prepro accepts the bitstream. If you are working with multichannel analog out connections, you better have the capability to boost that LFE by +15dB whenever any speakers are set to SMALL in the BD player. Many users are discovering that their downstream AVR/prepro can boost up to +10dB but NOT +15dB and complain about a lack of bass! Easy fix is to make sure all speakers are set to LARGE but this is not very ideal for typical bookshelf or satellite speakers (ie. not true fullrange).
4) DAC's play a large part in the final output. In most cases, AVR/prepro DAC's will be superior to a BD player's (this will be more true as we become increasingly digital). Most mid-range AVR/prepro's and BD players will have very comparable DAC's.
5) Some naysayers claim that jitter from PCM transmission over HDMI audibly affects the signal. Jitter involves the BD player's clock not being in line with the AVR/prepro's clock. Can be minimized or solved using technologies like Pioneer's PQLS or Denon's DenonLink.

Here's a quick recap about the PROS/CONS of deciding where the decoding needs to be done:

Decoding in the player and output via analog out

PROS - allows for mixing of secondary audio with primary audio for use with special features like PIP commentary, allows owners to reuse existing equipment, no jitter is possible

CONS - fixed crossover, cannot use automatic calibration settings, possible void in LFE if +15dB boost is not available


Decoding in the player and output via HDMI 1.1+

PROS - allows for mixing of secondary audio with primary audio for use with special features like PIP commentary, allows owners to use older HDMI AVR/prepros, calibration and full bass management possible with a fullrange PCM signal

CONS - possibility of introducing jitter with PCM transmission


Decoding in the AVR/prepro

PROS - all tools available, including calibration, full bass management, etc., no jitter possible

CONS - no secondary audio can be heard as it lacks the BD player's mixing capability (remember that most BD players allow you to toggle b/w mixing and bitstreaming)


The only exception to this rule is if somebody owns a high end AVR/prepro that allows redigitization of the analog signal for full manipulation. Once in the digital domain, then all the PROS above for the AVR/prepro may come into play.

Hope this answers the question in a definitive manner.

[My_Two_Cents]

This has been debated to death.

https://forum.blu-ray.com/showthread...light=decoding

But good write-up, just the same.

[EWL5]

Originally Posted by Ricshoe

This has been debated to death.

https://forum.blu-ray.com/showthread...light=decoding

But good write-up, just the same.

I realize that but I was never satisfied with speaking in "general terms." I tried to include specific issues and a hypothetical situation where decoding in either the player or the AVR/prepro would result in identical output.

Edit: Let me also add that although Sir Terrence and I share the same view that all decoders should be the same, I've gone a little further to explain why some users feel their AVR/prepro is doing a better job.

[prerich]

Originally Posted by EWL5

This question ranks right up there with "Which BD player should I get?" and "Can I hear the new lossless audio using my current receiver?" Unfortunately, the answer is not so clear cut given the different combinations of equipment in everyone's setup. If you had the option to choose either, which would you pick? I'm hoping to unmuddy that question with this post.

On a purely theoretical basis, the decoding done in the player should be identical to the decoding done in the AVR/prepro. This makes sense because both Dolby and DTS license hardware to perform at the same specifications. The legacy DTS sound I heard 5 years ago should sound the same in the newer receivers because the chips used are conforming to the same legacy spec (everything else being equal of course).

Having said that, why are there so many claims by users that decoding in the AVR/prepro sounds audibly better than when decoding in the player? Shouldn't they sound the same given the fact that decoding is just a simple unwrapping of PCM from the original codec? Yes and No and here's why:

Yes, decoding will sound the same
When the following conditions are met
1) The crossover in the BD player is the same as the one in the AVR/prepro
2) Delay/Level settings for each speaker channel approximate the settings arrived at when calibrating for the AVR/prepro
3) It is possible for the LFE to be boosted by +15dB in the downstream amp whenever speaker settings in the BD player are set to SMALL.

No, decoding will not sound the same
1) Most BD players have a fixed crossover (~100-150Hz). CE manufacturers arrive at this number based on the need to support the popular HTIB. AVR/prepro's on the other hand, allow a multitude of crossover settings to best match your situation. If I own decent bookshelves that go down to 60Hz or lower, you better believe I'd rather have the THX recommended 80Hz crossover over the fixed crossover in the player.
2) Most decent AVR/prepro's come with automatic calibration functions that attempt to correct for errant frequencies, nulls, etc. (examples include Audyssey, MCACC, etc.). Whether you go with the calibration settings or not, there's far more flexibility for equalization, delays, etc. with the AVR/prepro vs the BD player.
3) Boosting of LFE is always appropriately handled when the AVR/prepro accepts the bitstream. If you are working with multichannel analog out connections or PCM over HDMI 1.1+ connections, you better have the capability to boost that LFE by +15dB whenever any speakers are set to SMALL in the BD player. Many users are discovering that their downstream AVR/prepro can boost up to +10dB but NOT +15dB and complain about a lack of bass! Easy fix is to make sure all speakers are set to LARGE but this is not very ideal for typical bookshelf or satellite speakers (ie. not true fullrange).

Here's a quick recap about the PROS/CONS of deciding where the decoding needs to be done:

Decoding in the player

PROS - allows for mixing of secondardy audio with primary audio for use with special features like PIP commentary, allows owners to reuse existing equipment (even non-HDMI ones)

CONS - fixed crossover, cannot use automatic calibration settings, possible void in LFE if +15dB boost is not available


Decoding in the AVR/prepro

PROS - all tools available, including calibration, full bass management, etc.

CONS - no secondary audio can be heard as it lacks the BD player's mixing capability

The only exception to this rule is if somebody owns a high end AVR/prepro that allows redigitization of the analog signal for full manipulation. Once in the digital domain, then all the PROS above for the AVR/prepro may come into play.

Hope this answers the question in a definitive manner.

one of the best post that I have ever seen on this topic!

[aramis109]

Hrm, interesting. The +15 vs +10db must not be an issue with the PS3, as I certainly have no lack of bass. During playback of DVD's/legacy codecs, I've switched back and forth and can find little to no difference, and none in the LFE department.

[EWL5]

Originally Posted by aramis109

Hrm, interesting. The +15 vs +10db must not be an issue with the PS3, as I certainly have no lack of bass. During playback of DVD's/legacy codecs, I've switched back and forth and can find little to no difference, and none in the LFE department.

That is because the PS3 outputs a fullrange PCM signal after decoding. There is no option to select LARGE or SMALL speakers (it assumes all speakers are large and lets your AVR/prepro handle bass management). As stated in the first post, as long your AVR/prepro offers the nominal +10dB boost, you should be ok.

[aramis109]

Originally Posted by EWL5

That is because the PS3 outputs a fullrange PCM signal after decoding. There is no option to select LARGE or SMALL speakers (it assumes all speakers are large and lets your AVR/prepro handle bass management). As stated in the first post, as long your AVR/prepro offers the nominal +10dB boost, you should be ok.

Ah, nice. Thanks for the explanation.

[BIslander]

Originally Posted by aramis109

Hrm, interesting. The +15 vs +10db must not be an issue with the PS3, as I certainly have no lack of bass. During playback of DVD's/legacy codecs, I've switched back and forth and can find little to no difference, and none in the LFE department.

Originally Posted by EWL5

That is because the PS3 outputs a fullrange PCM signal after decoding. There is no option to select LARGE or SMALL speakers (it assumes all speakers are large and lets your AVR/prepro handle bass management). As stated in the first post, as long your AVR/prepro offers the nominal +10dB boost, you should be ok.

I believe the PS3 actually outputs an LFE channel that is the same level as the other channels, which makes it 10db low. (LFE is designed to be played 10db louder than the other channels.) The same is true of an uncompressed PCM track on a disc. LFE is recorded and sent 10db lower than the proper playback level.

In both of those cases, the digital software in the receiver knows that it needs to boost LFE by 10db. (The same thing happens with receiver decoding, btw. LFE is always recorded 10db low. The AVR does the decoding and then does the needed boost.) If bass management is engaged in the processor, then LFE gets dropped even further to make room for the redirected bass and the subwoofer output (LFE + redirected bass) will be boosted by 15db. With digital, all of those adjustments are transparent to the user. The software takes care of everything. Receivers don't even offer a digital subwoofer boost because it should never be needed.

Analog transmission is different. The end user has to apply the subwoofer boost in the receiver or at the sub itself.

[welwynnick]

Of course I've been itching to dive back into this debate for some time, but first I want to go back to this excellent post by EWL5 about amplifier decoding (which I've paraphrased). I whizzed through it first time, but only read it thoroughly yesterday, and something leapt out at me:

Originally Posted by EWL5

This question ranks right up there with "Which BD player should I get?" and "Can I hear the new lossless audio using my current receiver?" ......

On a purely theoretical basis, the decoding done in the player should be identical to the decoding done in the AVR/prepro.......

Shouldn't they sound the same given the fact that decoding is just a simple unwrapping of PCM from the original codec? Yes and No and here's why:

Yes, decoding will sound the same
When the following conditions are met

1) The crossover in the BD player is the same as the one in the AVR/prepro

2) Delay/Level settings for each speaker channel approximate the settings arrived at when calibrating for the AVR/prepro

3) For analog out, it is possible for the LFE to be boosted by +15dB in the downstream amp whenever speaker settings in the BD player are set to SMALL.

4) Identical DAC's used b/w the BD player and the AVR/prepro

5) ..when a player decodes and transmits the PCM via HDMI 1.1+ as the DAC's are used in the AVR/prepro....

No, decoding will not sound the same

1) Most BD players have a fixed crossover (~100-150Hz)... AVR/prepro's on the other hand, allow a multitude of crossover settings to best match your situation..... Analog users are at the mercy of the fixed crossover.

2) Most decent AVR/prepro's come with automatic calibration functions that attempt to correct for errant frequencies, nulls, etc. (examples include Audyssey, MCACC, etc.)....

3) Boosting of LFE is always appropriately handled when the AVR/prepro accepts the bitstream. If you are working with multichannel analog out connections, you better have the capability to boost that LFE by +15dB whenever any speakers are set to SMALL in the BD player.

4) DAC's play a large part in the final output. In most cases, AVR/prepro DAC's will be superior to a BD player's...

5) Some naysayers claim that jitter from PCM transmission over HDMI audibly affects the signal. Can be minimized or solved using technologies like Pioneer's PQLS or Denon's DenonLink.

Almost all the issues with amplifier decoding relate to D to A conversion, and not to bitstream to LPCM conversion. The exception is the final one, in bold. ELW5, if you think that any of the other nine issues apply to decompression, could you explain why, as I don't see it?

This leaves me with jitter as the explanation for the difference. There may be other issues, which have been discussed at AVS and AVF, but these seem to boil down to noise and interference on the LPCM signal from the player, and I would categorise those as jitter-like anyway.

There was some uncertainty expressed here about whether it was really as simple as that. That related to differences heard between the PS3 and stand-alone players when using a Pioneer SC-09TX receiver. That uses TI/BB SRC4192 sample rate convertors to buffer the digital audio stream. Similar SRCs in the SC-07 were shown to be very effective in jitter reduction, and it was presumed that the 09TX would perfrom at least as well. HiFi News tested both in the last few months, and found that the older but more expensive model actually had much higher jitter - 710ps vs 50ps, so this explianed why it would be sensitive to LPCM jitter from the PS3 in this example.

To reinforce this from my own point of view, I'm quite familiar with the effect of jitter on stereo replay. I've had two players and three amplifiers with i-link connections, and they all clean up music reproduction in ways that are very similar to amplifier decoding. The effects are familar and recognisable, and while there could be other explanations, I'm pretty convinced that it is indeed down to jitter.

Nick

[axe79]

Originally Posted by welwynnick

Of course I've been itching to dive back into this debate for some time, but first I want to go back to this excellent post by EWL5 about amplifier decoding (which I've paraphrased). I whizzed through it first time, but only read it thoroughly yesterday, and something leapt out at me:

Almost all the issues with amplifier decoding relate to D to A conversion, and not to bitstream to LPCM conversion. The exception is the final one, in bold. ELW5, if you think that any of the other nine issues apply to decompression, could you explain why, as I don't see it?

This leaves me with jitter as the explanation for the difference. There may be other issues, which have been discussed at AVS and AVF, but these seem to boil down to noise and interference on the LPCM signal from the player, and I would categorise those as jitter-like anyway.

There was some uncertainty expressed here about whether it was really as simple as that. That related to differences heard between the PS3 and stand-alone players when using a Pioneer SC-09TX receiver. That uses TI/BB SRC4192 sample rate convertors to buffer the digital audio stream. Similar SRCs in the SC-07 were shown to be very effective in jitter reduction, and it was presumed that the 09TX would perfrom at least as well. HiFi News tested both in the last few months, and found that the older but more expensive model actually had much higher jitter - 710ps vs 50ps, so this explianed why it would be sensitive to LPCM jitter from the PS3 in this example.

To reinforce this from my own point of view, I'm quite familiar with the effect of jitter on stereo replay. I've had two players and three amplifiers with i-link connections, and they all clean up music reproduction in ways that are very similar to amplifier decoding. The effects are familar and recognisable, and while there could be other explanations, I'm pretty convinced that it is indeed down to jitter.

Nick

Hi guys, whilst I am at a disadvantage to many of you here who take a far more Lab measured approach, (and maybe have the facilities) I do have many years of domestic real world experence.
Many on this board appear to be USA based.
In the UK, Meridian are regarded as making some of the best High End equipment and have been cutting edge with much of it. I own a 207CD/pre amp, (2 box) regarded as the best CD player in the world when 1st brought out. CD players ALL have issues with the clock reading info off the disc and 'superclocks' with better circuit design have been made to improve things.
Years ago with the help of Russ Andrew I modified this player to a high degree. Incidently I obtain the same Hi End sound off a Hard Drive today!

There is a difference in the interaction between the PS3 and the Receiver on LPCM v Bitstream OTHERWISE THEY WOULD BOTH SOUND IDENTICAL and they don't. It looks like what is going on is very similar to what was/is still happening with CD players.
Logic tells me that if the PS3 (with all the updates installed) has a variable in the delivery of the information down the HDMI cable the issue is 'inside the player'!
Now I have a Totally seperate Dedicated Mains spur connected up to Two
Mains transformers/mains capacitors/surge protection circuits (British Telecom ones for Main Frames etc) (The Russ Andrews ones are £2750 each!) which feeds the equipment in as clean manner that is possible.
No RFI, no Mains noise off other circuits, no voltage surges or spikes.
Fed with a 'perfect feed' clear differences can be heard.

Sony cannot by software updates ever make the PS3 put out in full Bitstream like its newer players can, which on Vision & Sound show improvements. So it is really about getting the most out of the various settings available.
And that is a big can of worms!

[EWL5]

Originally Posted by welwynnick

Of course I've been itching to dive back into this debate for some time, but first I want to go back to this excellent post by EWL5 about amplifier decoding (which I've paraphrased). I whizzed through it first time, but only read it thoroughly yesterday, and something leapt out at me:

Almost all the issues with amplifier decoding relate to D to A conversion, and not to bitstream to LPCM conversion. The exception is the final one, in bold. ELW5, if you think that any of the other nine issues apply to decompression, could you explain why, as I don't see it?

This leaves me with jitter as the explanation for the difference. There may be other issues, which have been discussed at AVS and AVF, but these seem to boil down to noise and interference on the LPCM signal from the player, and I would categorise those as jitter-like anyway.

There was some uncertainty expressed here about whether it was really as simple as that. That related to differences heard between the PS3 and stand-alone players when using a Pioneer SC-09TX receiver. That uses TI/BB SRC4192 sample rate convertors to buffer the digital audio stream. Similar SRCs in the SC-07 were shown to be very effective in jitter reduction, and it was presumed that the 09TX would perfrom at least as well. HiFi News tested both in the last few months, and found that the older but more expensive model actually had much higher jitter - 710ps vs 50ps, so this explianed why it would be sensitive to LPCM jitter from the PS3 in this example.

To reinforce this from my own point of view, I'm quite familiar with the effect of jitter on stereo replay. I've had two players and three amplifiers with i-link connections, and they all clean up music reproduction in ways that are very similar to amplifier decoding. The effects are familar and recognisable, and while there could be other explanations, I'm pretty convinced that it is indeed down to jitter.

Nick

I personally have not heard the difference b/w jitter from LPCM over HDMI vs bitstreaming as I don't own a receiver that can decode the new codecs. At this time, I believe current jitter reduction circuitry only applies to stereo and not multichannel (more for CD's than movies). The Denon A1UDCI may be the first BD player to incorporate jitter reduction for multichannel using DenonLink+HDMI simultaneously but the language is not clear.

Read about it here:

http://www.usa.denon.com/DVDA1UDCI.blurayrel.Final.pdf

It was hoped that the Pioneer 09 flagship BD player would have multichannel PQLS but I think it is also restricted to 2-channel.