Analog vs. Digital Path

[glennm0270]

I know this question exposes my ignorance...come to think of it, I guess that's where all questions originate from. Anyway...

Suppose I were to rip CDs with FLAC (which is supported on the native hardware of the SB3) and pump them to the SB3. Furthermore, suppose I owned a pretty good preamp (maybe an NAD Master). Now, if I'm understanding this correctly, I have two choices for sending the sound to my speakers:

1) Use the digital connection, which will then mean the NAD's DAC will do the conversion
2) Use the analog connections, which will mean the SB3 will do the conversion and the NAD will just pass the analog signal to the amp

First, do I have those two options correct?

Second, which should produce the better sound path? Is it all pretty much dependent on which has the better DAC? In other words, if I were hooking the SB3 to a cheaper receiver (Onk TS575, eg), is it likely that the DAC on the SB3 would be better than the Onk, which would imply that I should use the analog connectors?

TIA!

[Mark Lanctot]

1) Use the digital connection, which will then mean the NAD's DAC will do the conversion
2) Use the analog connections, which will mean the SB3 will do the conversion and the NAD will just pass the analog signal to the amp

First, do I have those two options correct?

Yup!


Second, which should produce the better sound path? Is it all pretty much dependent on which has the better DAC? In other words, if I were hooking the SB3 to a cheaper receiver (Onk TS575, eg), is it likely that the DAC on the SB3 would be better than the Onk, which would imply that I should use the analog connectors?

Depends on many factors. The best thing to do is experiment.

Personally I found that you're not only comparing the DACs between the SB3 and the receiver / pre/pro, you're comparing a receiver / pre/pro's analog implementation to its digital implementation. In my case the analog implementation was worse than the digital implementation, even though the SB3s DAC is probably at least as good or better than the DAC in my receiver. The analog path likely has too many conversions, analog -> digital through an ADC so it can go through the DSP, then back to analog through the DAC. Made things quite muddy. I guess a more fair comparison would be to use the receiver's "direct" mode which bypasses the DSP and the extra conversion step. The headphone output, which uses the SB DAC directly, doesn't sound as muddy. But I like Dolby Pro-Logic IIx Music mode, which uses the DSP.

It's hard to get analog right!

[glennm0270]

Thanks for the quick reply! My tendency is to always go with the digital connections, but I'd rather not make that decision in ignorance. I'm okay to make it through stubborness or stupidity, though :)

[Mark Lanctot]

NAD makes some fairly high-spec equipment though. It may handle analog signals very well.

Experiment around and see which one you like better.

[Mike Meyer]

This was a good thread for me to read. When I read Mark's response that mentioned Dolby Pro-Logic IIx Music mode, that made me realize that I hadn't played around with the different modes on my receiver. I was just using the 7ch Stereo mode that I like when watching TV. So I switched it last night to Pro-Logic IIx Music and it sounds alot better now. This weekend I'll try some other modes too like DTS/NEO 6: Music or something like that. :) I suppose I should try the analog test too.

Good post Mark.

[Mark Lanctot]

This was a good thread for me to read. When I read Mark's response that mentioned Dolby Pro-Logic IIx Music mode, that made me realize that I hadn't played around with the different modes on my receiver. I was just using the 7ch Stereo mode that I like when watching TV. So I switched it last night to Pro-Logic IIx Music and it sounds alot better now. This weekend I'll try some other modes too like DTS/NEO 6: Music or something like that. :) I suppose I should try the analog test too.

Good post Mark.

...wait 'till you hear a TV program that's specifically encoded in a matrix surround format like Dolby Surround or SRS TruSurround. Look for the logo on the end credits.

Programs like CSI and (late) Star Trek:TNG. The Simpsons has been recorded in Dolby Surround for many years but don't use it effectively.

Of course, this has largely been superseded by digital TV where you can have Dolby Digital sound in true 5.1. But even with this setup, not all channels are Dolby Digital all the time.

Channel separation is quite good in PLII/PLIIx but you get perfect channel separation in DD (they are discrete) and much better dynamic range.

PLII/PLIIx will also work on regular stereo material (i.e. not matrix-encoded) like CDs or the output from a Squeezebox, just to get back on topic. :-) The effects will be more diffuse rather than intended/directed in material that's encoded. The decoder is very sophisticated and quite subtle, not at all like those horrid manufacturer-included DSP modes like "hall", "jazz", "stadium", "live" etc. It was made at great effort and great expense and came from two genuises of the business, Dolby and Jim Fosgate. See the complete story here: http://www.stereophile.com/interviews/1204fosgate/

If you have a 7-channel system, note that Dolby Pro-Logic IIx is the only 7-channel matrix decoder, although if you have a harman/kardon receiver you also have Logic7. DTS Neo:6 is a 6-channel matrix decoder - your rear channels will be in mono rather than stereo with PLIIx.

In regards to the subject of this thread, PLII/PLIIx will probably work better on digital signals because there's one less A-D conversion required, but higher-end equipment minimizes the drawback.

[Mike Meyer]

Thanks for the additional information. My receiver is a Pioneer VSX-1015TX which is a 7-channel receiver but my speaker setup is only 5.1. I will try the different modes while watching certain tv shows and also listening to music to see what sounds the best.

My previous HTIB had those DSP modes like 'hall', 'jazz' and 'live' and I remember not thinking much of them. :) I'll stick to the various Dolby/DTS modes on my current receiver.

I enjoy reading all these forums including the Audiophile forum (although I think I understand about 10% of what I read there). But now when I go back and read the specs on my receiver it makes a lot more sense now so maybe some of it is sinking in.

I'm anxious to try this out this weekend. Good article on Fosgate too. Thanks again.