Digital Output or Analogue Output for 5.1 playback? (1 Viewer)

[Jeffrey Wiffen]

For a couple years now I have been feeding a digital signal from my Toshiba SD4800 (DolbyD 5.1 decoder equipped) to my NADT760 (DolbyD 5.1 and DTS 5.1 decoder equipped) with a decent WireWorld digital-coax cable.

I recently decided to buy six interconnects so I could utilize the DVD players DVD-Audio decoder.

The other night I decided to try out listening to a DolbyD 5.1 movie soundtrack via the DVD players six analogue outputs and not the digital-caox output, opting to use the DVD player's DolbyD 5.1 decoder instead of the NAD's DolbyD 5.1 decoder.

I was shocked at the results. When I switched from the digital output to the analogue output my rear speakers came alive in a way I never thought possible. The dialogue was cleaner and more focused. Each speaker seemed more distinct and seperate. The bass was tighter. All around I found it to be a more pleasant listening experience.

The problem is that the SD4800 DVD player has NO bass management, whatsoever. My B&W bookshelf speakers seemed to be working overtime as a result. Plus, my sub was nearly (not completely) innactive.

Still the sound was always significantly better whenever I switched from the digital-coax over to the analogue outs. Much better!

I feel I need to get to the bottom of this. You see, it's driving me crazy knowing that all this time I haven't been realizing the true potential of these movie soundtracks.

Call me crazy, but I would prefer to feed a digital signal to my NAD receiver than to use the analogue signal.

Questions:
Is it a cable issue? Is my digital-coax cable not feeding my NAD receiver a good enough signal? Should I purchase a better digital-coax cable? Or, is it that the NAD's decoder is inferior to the Toshiba decoder? Or, am I missing something?

Please advise.

Thanks!

 

[Scott Merryfield]

Did you calibrate the speaker levels via your Toshiba DVD player's on board DD/DTS decoder? Also, have you calibrated your speakers via your NAD receiver for use with its DD/DTS decoder? If not, your surround speakers may appear to sound "better" with the DVD player's decoder because they are louder than they should be (or, at least, louder than via the NAD's DD/DTS decoder).

 

[Michael Reuben]

As an extension of Scott's question: Had the NAD been properly calibrated with an SPL meter and test tones? If not, it's possible that the deficiencies you've now identified in the NAD's playback are simply a result of the levels for rear and center speakers being set too low.

M.

 

[Cliff Olson]

I did the same thing just 2 weeks ago, after purchasing a used Sony TA-P9000ES. I knew SACDs would be amazing in 5.1, but even movie soundtracks sound much better being decoded inside the DVD Player - not to mention redbooks. I've had it calibrated with an SPL Meter - the Lexicon DC-1 Preamp, and the Sony DVD Player, so levels are the same. It's just the different DACs, I guess. Glad you experienced the same euphoria I did, Jeffrey! Oh, and to answer a few of your questions:

No, I'm sure it's not your coax, because I'm using -- was using, a Kimber D-60 Coax (considered by many to be one of the best).
I suspect, your DACs in the Toshiba are superior to the ones in your NAD.

 

[Jeffrey Wiffen]

Thanks for all the responses. I can't say that I am impressed though. It pisses me off that my $200 DVD player has better a decoder and/or DACs than my $1500 receiver.

I mean, the difference was night and day! It's not just that things were louder as Merryfield suggested. It was just "better" in every possible way.

Unfortunately, my DVD player does not have a DTS decoder. So I will still have to use my digital-coax connection for these tracks.

I still think I may demo a couple different coax cables (maybe even a tos-link optical cable) to see if I can improve the sound using my receivers onboard decoders.

My only issue still, is the bass management issue. The sub only became active occasionally, and when it did was only minimal. However, my bookshelf speakers setup (B&W DM303s) have never sounded better! They put out some serious bass, for their size.

 

[Vin]

My only issue still, is the bass management issue. The sub only became active occasionally, and when it did was only minimal. However, my bookshelf speakers setup (B&W DM303s) have never sounded better! They put out some serious bass, for their size.

Due to the lack of bass management of your SD4800 your speakers are receiving the entire frequency as encoded for those channels, with only the LFE signal going to your sub.

With the digital connection to your NAD, with speakers set to small, the bass from those channels as well as the LFE was being reproduced by your sub.

It's very likely that this is the difference you're hearing.....

Vin

 

[Cliff Olson]

Thanks for all the responses. I can't say that I am impressed though. It pisses me off that my $200 DVD player has better a decoder and/or DACs than my $1500 receiver.

A receiver must do many different things, Jeffrey. A quality (or lack of it) DAC is only one of many expenses put into it I hear you though. I thought Lexicon used one of the best DACs on the market... Until I started listening to the Sony DVD Player's.

 

[Scott Merryfield]

I mean, the difference was night and day! It's not just that things were louder as Merryfield suggested. It was just "better" in every possible way.

Human hearing perception is such that we usually consider the louder sound to be of higher quality. Unless you have calibrated your speaker levels for both your DVD player's DD/DTS decoder and your receiver's decoder (and then compare both at the same voulme level), I would not jump to any conclusions as to which truly sounds better. The player's decoder very well could sound better, but the only way to validate that is with a properly calibrated speaker system.

 

[Michael Reuben]

I thought Lexicon used one of the best DACs on the market...

They do, but you were using a DC-1, which is probably about seven years old, and DACs have improved. I'm not sure what vintage player you're using, but it's probably a lot more recent.

M.

 

[dave alan]

One further thing to consider is jitter
which is introduced by the digital coax or toslink cable when sending the digital signal from your player to an external DAC (your NAD)

Although jitter is generated by other parts of the signal chain, this digital cable, or transmitter induced jitter is eliminated by letting the player do the conversion to analog.

I also hear a difference and have used the 'bypass' mode on my Pre-pro exclusively for about a year. There are other sonic advantages with analog connections as well.

What you sacrifice is DD EX and DTS ES as well as matrixed modes like Logic 7 and Cirrus Extra (6.1 and 7.1), but for 5.1, assuming your player has good DACs, analog is the way to go, for me.

Also, speaker distance placement is more critical, as you lose time alignment, but, to me, digital time alignment on most pre pros isn't all that and placement is always critical anyway.

I suggest the Outlaw Audio ICBM if your pre has no analog BM. It's a quality analog BM device at a steal of a price.

 

[Cliff Olson]

Human hearing perception is such that we usually consider the louder sound to be of higher quality. Unless you have calibrated your speaker levels for both your DVD player's DD/DTS decoder and your receiver's decoder (and then compare both at the same voulme level), I would not jump to any conclusions as to which truly sounds better. The player's decoder very well could sound better, but the only way to validate that is with a properly calibrated speaker system.

Very interesting. Have you ever heard compressed CDs? They are usually MUCH louder, than, say a MoFi CD of the same title. And, to the 'average' person, they DO sound better. I sure in the hell don't think the compressed CD sounds better, even though it's substantially louder... So, in my experience, louder almost always sounds worse - unless it's even cleaner than the 'quiter' source. But, if it's cleaner AND louder, than it's obviously better, IMO

 

[Andy_A]

1. Buy a $12 Canare digiflex gold digital coax and do not look back. Unless you have a ground loop issue--then buy a $20 toslink.

2. For playback, I normally do not notice any difference playing back dd/dts sources from dvd vs. preamp assuming I have correctly set the listening levels with a spl meter. The ICBM is highly recommended, though. With this device, you should run all dd/dts/dvd-audio from the dvd player with speakers set to "large". The above posts are correct in saying the differences you are hearing are due to set up in the pre/pro. Hope this helps.

 

[ReggieW]

I have a NAD T762 and Denon 2900 and ALWAYS allow the T762 to do the processing for movies. For one, I then have real bass management and don't run into those problems like I do with multi-channel hi-res music when using the analog outs. The Denon 2900 DOES have a better DAC than the NAD, but the greater flexibility, ease of use, and better bass management, makes up for any perceived audio improvement that the 762 may appear to offer.

Reg