Multi-channel audio over HDMI

[Mars]

Hi - new to the forum and have had my system for about 6 months now. Forgive me if this is an obvious question, but now that the new software upgrade will include multi-channel audio over HDMI, I was wondering if people thought that, as a general rule, audio quality would be better over HDMI or the separate digital audio output. (everything is run through an Anthem AVM 50 on my system). Not sure if it is too early to ask this question because the release just came out.

When the dealer originally set me up, they had everything over HDMI, until I told them it just didn't sound right and that I felt I was getting any surround/good LFE. They set up a Digital audio cable and it sounded great...it wasn't until today that I realized I was only getting two-channel Dolby and no DTS (which also now explains why I could never hear the DTS "intro" on the Kaleidescape Intros DVD).

Anyway, any advice is appreciated...thanks

 

[JerryL]

Your audio in general is better off over the SPDIF (not HDMI). The reason is HDMI has horrible jitter. For the high res audio formats that Blu Ray and HDDVD have you are stuck with HDMI.

 

[Steven]

Good Audio

Hi,

Where does optical audio fit in here? Lasers are good :>

Thanks, Steven

 

[JerryL]

Optical=SPDIF. Coax=SPDIF. HDMI= uh, HDMI.

I think coax gives you better sound quality but optical is not an electrical connection so if connecting a computer you can avoid transferring any noise from the computer this way.

 

[BritBlaster]

Where is your source that HDMI has worse jitter than the other connections ?

My experience has been that it's all down to incompatibility (and anecdotally as expressed here). My SSP-800 accepts audio over HDMI, but it doesn't sound as good as when the audio comes from SPDIF because the processor doesn't recognize it as multi-channel audio. I think the reason is that the handshaking between the player/processor isn't working properly for multi-channel audio, and I think this is probably quite common.

 

[Riskky]

As a rule... Coax better than Optical... Optical better than HDMI, HDMI = the cable of the devil!

HDCP Handshaking is always the issue, but we now have ways around it... and we can now mske our own custom length HDMI cables too, but watch us fight Sky to get a HD box with component outputs.

Incedentally Kaleidescape are also at pains to ensure you fit a mini player to the back of a telly the right way up (connector panel to the top) because... yep. hdmi cables fall out!

 

[JerryL]

Where is your source that HDMI has worse jitter than the other connections ?

My experience has been that it's all down to incompatibility (and anecdotally as expressed here). My SSP-800 accepts audio over HDMI, but it doesn't sound as good as when the audio comes from SPDIF because the processor doesn't recognize it as multi-channel audio. I think the reason is that the handshaking between the player/processor isn't working properly for multi-channel audio, and I think this is probably quite common.

You are correct that HDMI presents all kind of connection issues due to handshaking. That is different from the issue of audio jitter- which is a real issue with digital signals. My source is having read several interviews with J. Robert Stuart of Meridian Audio fame. He knows a thing or two about digital audio (massive understatement). He has been telling we Meridian fans for a long time now that HDMI has terrible terrible jitter and its a real issue. I should say if you are using a receiver and don't have a really high end setup the jitter issue shouldn't be that important. But if you are after getting the best result possible it becomes more problematic.

Check here:
http://www.avsforum.com/avs-vb/showthread.php?t=1134289
In the Feb 2009 edition of the Hi-fi News magazine Paul Miller measured the following jitter results for a few A/V amplifiers:

Denon AVR-3803A
---------------
SPDIF: 560psec
HDMI: 3700psec

Onkyo TX-NR906
---------------
SPDIF: 470psec
HDMI: 3860psec

Pioneer SC-LX81
---------------
SPDIF: 37psec
HDMI: 50psec

Yamaha RX-V3900
---------------
SPDIF: 183psec
HDMI: 7660psec

http://www.meridian.co.uk/product-model/accessories/hd621-hdmi-audio-processor.aspx

Finally my own experience is limited to 2 channel comparisons because I could not output multichannel audio before i got my Meridian 621 HDMI processor but I hear a noticeable difference in the smoothness of the sound with the 621. I don't see much, if any, difference in image quality though.