Pure Direct vs Stereo

[AcuDefTechGuy]

HDMI cannot transmit audio without video and it packs the audio in the frames between the video.
The stream has to be packed and unpacked, placed back in a buffer and then properly clocked.
Whereas, COAX is streamed directly.

None of that should be a problem, but I have found that HDMI and COAX can sound different.
I am not sure if it is jitter, but HDMI receivers have been shown to have orders of magnitude more than COAX.

I am not trying to say that folks will find a difference, if you are intersted in experimenting, it is something to try.
After all, there should be no difference between Direct and Pure Direct but many folks had found that there is.

- Rich

Anything is possible.

 

[Grador]

HDMI cannot transmit audio without video and it packs the audio in the frames between the video.
The stream has to be packed and unpacked, placed back in a buffer and then properly clocked.
Whereas, COAX is streamed directly.

None of that should be a problem, but I have found that HDMI and COAX can sound different.
I am not sure if it is jitter, but HDMI receivers have been shown to have orders of magnitude more than COAX.

I am not trying to say that folks will find a difference, if you are intersted in experimenting, it is something to try.
After all, there should be no difference between Direct and Pure Direct but many folks had found that there is.

- Rich

Not to say that you aren't right, I can see this being true, but coax isn't exactly a completely direct stream either. From my knowledge of how SPDIF works I think it could be even more prone to jitter error given that you are at the mercy of the clocks at both ends of the chain, while on HDMI you're only worried about the post buffer clock on the DAC end.

 

[Irvrobinson]

I was under the impression that a balanced system was able to provide more voltage to the amp from the pre-amp? Whether or not that's important is another question.

That's not correct. There's nothing inherent about a balanced cable that carries more voltage, though many components, especially in pro-audio, provide a lower input impedance on a balanced connection, which increases the current carried by the cable. The increased current will also help decrease the resistance to EMI, but that's not an inherent characteristic of balanced cables.

Frankly, I think TLS Guy is understating the value of balanced cables for any connection over about six feet long. Common mode rejection is a big theoretical and measurable advantage, and given how many cables many modern systems have and how long they can be, dismissing balanced cables is misguided. This isn't some BS voodoo cable reasoning, differential signaling is an important foundation of modern electronics. And that comment about solid state electronics having asymmetric phase splitter logic vulnerability is just poppycock.

I run 35 foot cables between my pre-amp and amp, and I wouldn't consider a single-ended run that long, especially with the myriad of speaker cables, subwoofer cables, and power cables in the vicinity of the amp. Then there's the difference between the cheap, friction-fit, RCA-style connectors and XLR connectors, like those from Neutrik or Amphenol, and that seals the deal for me.

 

[3db]

That's not correct. There's nothing inherent about a balanced cable that carries more voltage, though many components, especially in pro-audio, provide a lower input impedance on a balanced connection, which increases the current carried by the cable. The increased current will also help decrease the resistance to EMI, but that's not an inherent characteristic of balanced cables.

The voltage measured across a differential input is greater than that of the voltage of a single ended input measured from either + or -v input and ground. This larger voltage and the common mode rejection inherent in diffential systems allows for longer cable runs than single ended cables. That's what TLS was getting at.

I would not run differential if my interconnects were under 6' unless in a noisy rf environment. It provides no sonic advantage in a noise free environment with short interconnects.

 

[Irvrobinson]

The voltage measured across a differential input is greater than that of the voltage of a single ended input measured from either + or -v input and ground. This larger voltage and the common mode rejection inherent in differential systems allows for longer cable runs than single ended cables. That's what TLS was getting at.

What higher voltage are you talking about?

 

[3db]

The voltages at the pre-amp differential outputs.

 

[Irvrobinson]

The voltages at the pre-amp differential outputs.

The signals are just mirrored polarities of the original signal. The peak-to-peak voltages on each conductor is one half of the peak-to-peak voltage of the combined differential signal. CMRR is real, but I'm not seeing your voltage argument.

 

[3db]

The signals are just mirrored polarities of the original signal. The peak-to-peak voltages on each conductor is one half of the peak-to-peak voltage of the combined differential signal. CMRR is real, but I'm not seeing your voltage argument.

That's correct that voltages are mirrored. The voltage is peak to peak with respect to either input, hence the higher voltage. A single ended input is actually half that value or peak value because its measured with respect to ground. Therefore the higher voltages at the differential inputs. You can't measure a differential input with respect to ground. Its measured with respect to the inputs.

 

[Grador]

That's correct that voltages are mirrored. The voltage is peak to peak with respect to either input, hence the higher voltage. A single ended input is actually half that value or peak value because its measured with respect to ground. Therefore the higher voltages at the differential inputs. You can't measure a differential input with respect to ground. Its measured with respect to the inputs.

I don't think peak to peak matters in this case. The inverse signal is only used for CMRR, so in a sense you're only the single end voltage comprises the signal while the other is just used as a comparison.

 

[3db]

I don't think peak to peak matters in this case. The inverse signal is only used for CMRR, so in a sense you're only the single end voltage comprises the signal while the other is just used as a comparison.

I don't think that is correct. A differential amp amplifies the difference between the two inputs, not the voltage applied to either terminal with respect to ground. I believe the 2nd signal is not there for a comparison sake. Its an integral part of determining the difference between the inputs. Differential amps are very different in operation than a single ended amp.

 

[Grador]

I don't think that is correct. A differential amp amplifies the difference between the two inputs, not the voltage applied to either terminal with respect to ground. I believe the 2nd signal is not there for a comparison sake. Its an integral part of determining the difference between the inputs. Differential amps are very different in operation than a single ended amp.

Ok, that sounds reasonable enough.

 

[Irvrobinson]

I believe the 2nd signal is not there for a comparison sake. Its an integral part of determining the difference between the inputs. Differential amps are very different in operation than a single ended amp.

This is correct, but that's not relevant to the voltage on the conductors. There's not 3db more voltage on the wire, 3db.

 

[3db]

This is correct, but that's not relevant to the voltage on the conductors. There's not 3db more voltage on the wire, 3db.

The voltage differential measured across the wires of a differential input is greater than that of a single ended measured with respect to ground.

 

[JonnyFive23517]

Thats part of the discussion. It appears that on Marantz (still checking on SR-6006) & Denon (at least 3312 & up) even in Pure Direct Mode, you can still get subwoofer output. I don't know if this is called "bass management" or just "simple bass output".

The fact is, you can get subwoofer output even in PD/D on at least some Marantz & Denon, but you can't with Onkyo & Yamaha, etc.

AcuDefTechGuy, I owe you a huge apology. A long time ago I had my sub set to LFE+main, so I assumed it was still there. There was no subwoofer in direct mode. But last night I checked, and sure enough it was just set to LFE. Changing the setting I now get subwoofer in direct/pure direct mode.

Really sorry for my error, you were totally right! -Jon

 

[AcuDefTechGuy]

AcuDefTechGuy, I owe you a huge apology. A long time ago I had my sub set to LFE+main, so I assumed it was still there. There was no subwoofer in direct mode. But last night I checked, and sure enough it was just set to LFE. Changing the setting I now get subwoofer in direct/pure direct mode.

Really sorry for my error, you were totally right! -Jon

No prob.

It seems like Denon + Marantz are the only ones to feature PD 2.1 mode.

But Stereo 2.1 is all good too if the AVR can't do PD 2.1. All good.

 

[cr136124]

New owner of a Denon 4311CI!

I'm trying to use Direct and Pure Direct + my subs and it is not working for me!

Here are the settings that I used:

Speaker Setup -> Bass Setting -> Subwoofer Mode -> LFE+Main
Speaker Setup -> Bass Setting -> LPF for LFE -> 100Hz

Audio Setup -> 2ch Direct/Stereo -> Setting -> Custom

Front - Small
Subwoofer - Yes
SW Mode - LFE
Crossover - 80Hz
Distance FL 10.8ft
Distance FR 11.0ft
Level FL 0.0dB
Level FR 0.0dB

Could you please tell me what am I missing?

 

[AcuDefTechGuy]

New owner of a Denon 4311CI!

I'm trying to use Direct and Pure Direct + my subs and it is not working for me!

Here are the settings that I used:

Speaker Setup -> Bass Setting -> Subwoofer Mode -> LFE+Main
Speaker Setup -> Bass Setting -> LPF for LFE -> 100Hz

Audio Setup -> 2ch Direct/Stereo -> Setting -> Custom

Front - Small
Subwoofer - Yes
SW Mode - LFE
Crossover - 80Hz
Distance FL 10.8ft
Distance FR 11.0ft
Level FL 0.0dB
Level FR 0.0dB

Could you please tell me what am I missing?

On Audio Setup, change Front to LARGE & SW Mode to LFE+Main.

 

[AcuDefTechGuy]

Someone recently send me a PM asking me which speakers are my fav?

I told him my "fav" kind of changes from month to month.

But right now, thanks to this Pure Direct 2.2, my current fav are the ORION + SX1010N + AVR5308 + AT6012 (Apple Lossless music from iPad to Apple TV). I'm listening to Dark Knight Rises soundtrack right now. It is kicking my a$$ like there's no tomorrow.

 

[cr136124]

On Audio Setup, change Front to LARGE & SW Mode to LFE+Main.

Thanks a lot!!!

My ultras are working now using Pure and Pure Direct.



Pretty cool........I have one Quick Select for Movies, one for Stereo with Audyssey Byp. L/R and, now one for Direct/Pure Direct.

Thanks again!

 

[RichB]

Someone recently send me a PM asking me which speakers are my fav?

I told him my "fav" kind of changes from month to month.

But right now, thanks to this Pure Direct 2.2, my current fav are the ORION + SX1010N + AVR5308 + AT6012 (Apple Lossless music from iPad to Apple TV). I'm listening to Dark Knight Rises soundtrack right now. It is kicking my a$$ like there's no tomorrow.

Like any good parent, you love all your children equally but at any given time...

- Rich