[Tony1]

I know HDMI sends video and audio but was wondering if there was any advantage HDMI has over coax at sending digital audio signals.  Especially curious if the new audio format for blue ray, DTS HD & Dolby Digital HD, would sound better through HDMI or coax.

[Phil A]

HDMI 1.3 is capable of carrying 2 channels of 768k audio, far more than coax.  The full bandwidth of the audio with the new hi-def video formats cannot be passed via coax.

[Phil A]

FYI - here is a brief history of past and present versions of HDMI and the technical capability:

http://www.hometheaterdiscussion.com/forums/showthread.php?t=7651&highlight=hdmi

[MaxCast]

What makes one wire suitable for higher bandwidth than another? 

[Phil A]

What makes one wire suitable for higher bandwidth than another? 

It is not necessarily the wire alone.  Different type of connections offer don't rely on the same technology.  USB can be 1.1 or 2.0, there is different memory speed on different chips, a CD is the same size as a DVD but DVD is a different technology.  The maximum data rate for audio on DVD-V is specified as 6.144 Mbps. It can be sampled at 48 or 96 kHz with 16, 20, or 24 bits/sample. There can be from 1 to 8 channels with DVD-V . 8 channels of 48/16 = 6.144 Mbps.   2 channels of 96/24 = 4.608 Mbps.  Coax and the technology of sending signals over it is limited by specifications and the fact it is a single conductor.  It does not mean that someone could not re-design the spec and have some technology that can do a bit better the way USB 1.1 or 2.0 look identical but are not.  I'm not an engineer so I can't really speak to the limitations of current technology.  The reality of the situation is that HDMI is a one-way digital signal and there are studios concerned with issues related to copyright protection.  HDMI was really designed for the PC (and to be a 6 ft. or less length) and that's why on the original generation of cabling distance was more of a factor.  Newer cables (nothing to do with versions of HDMI) have thicker conductors.  It's not unlike the 'S' Video connection that has thinner conductors and is really not designed to go over a certain distance.

[James Tanner]

What makes one wire suitable for higher bandwidth than another? 

It is not necessarily the wire alone.  Different type of connections offer don't rely on the same technology.  USB can be 1.1 or 2.0, there is different memory speed on different chips, a CD is the same size as a DVD but DVD is a different technology.  The maximum data rate for audio on DVD-V is specified as 6.144 Mbps. It can be sampled at 48 or 96 kHz with 16, 20, or 24 bits/sample. There can be from 1 to 8 channels with DVD-V . 8 channels of 48/16 = 6.144 Mbps.   2 channels of 96/24 = 4.608 Mbps.  Coax and the technology of sending signals over it is limited by specifications and the fact it is a single conductor.  It does not mean that someone could not re-design the spec and have some technology that can do a bit better the way USB 1.1 or 2.0 look identical but are not.  I'm not an engineer so I can't really speak to the limitations of current technology.  The reality of the situation is that HDMI is a one-way digital signal and there are studios concerned with issues related to copyright protection.  HDMI was really designed for the PC (and to be a 6 ft. or less length) and that's why on the original generation of cabling distance was more of a factor.  Newer cables (nothing to do with versions of HDMI) have thicker conductors.  It's not unlike the 'S' Video connection that has thinner conductors and is really not designed to go over a certain distance.

Very informative  Phil - thanks.

james

[Tony1]

Phil A

Given your description of the HDMI cable, do you think that there would be an advantage to using HDMI in audio bypass mode like in the SP2 or future SP3 vs XLR or RCA interconnects?

Tony

[Phil A]

Phil A

Given your description of the HDMI cable, do you think that there would be an advantage to using HDMI in audio bypass mode like in the SP2 or future SP3 vs XLR or RCA interconnects?

Tony

Tony - the HDMI connection will be digital so you could use the 'pass thru' function vs. going thru other DSP modes but not 2 or 6 channel bypass the way you do with analog RCA or XLR connections.  With an HDMI digital connection you will have full advantage of the bass management functions in the Bryston pre/pro.  With XLR or RCA multi-channel connections in bypass mode you will need to use the bass management in the player.  Typically players don't have the same flexibility and usually have a pre-assigned crossover when you set speakers to small.  This may be 100HZ or whatever is built into the particular player.  Also with analog XLR or RCA inputs you have 5.1, not 6.1 or 7.1

I have an SP1.7 and I'm waiting to see as what shakes out.  Bass managment to me is not necessarily as big a deal to most.  I have 4 Rel subs, 2 Storm IIIs for the front channels, a Q150 for the center and a Strata III for the rears.  So when I watch movies or listen to multi-channel music I have my own bass management.  Obviously much depends on pricing.  I could get a high quality 5.1 switcher from Zektor.  I don't hate multi-channel music but prefer stereo most of the time.  I also am quite content with current DVDs and won't be doing anything hi-def until an upgrade the projector (mine can do 720p but no HDMI or DVI) in the main system.  So I'll see where upgrades go with my current Bryston unit and then I can decide what to do with the rest of the stuff.  By that time the prices for the hi-def video formats won't get higher and prices for 1080p projectors are coming down too. 

I also have 3 systems (main, bedroom and basement) and while I don't use anything but the main system much for movies, before I jump into a new format I'd like to be able to have the ability to play it in at least the bedroom system.  The bedroom system backs to the main system so all it may mean is an HDMI splitter and a new rec'r.