Discuss Receiver Surround modes, What should you use? in the Home Theater - Audio / Video forum. on the subject of optical mediums used for audio transmission...
there are two good reaosns a typical TOS based optical ...
on the subject of optical mediums used for audio transmission...
there are two good reaosns a typical TOS based optical connection can not carry the need data for multichannel uncompressed audio...
let me start by saying this. it irritates me somewhat that all too offen people take a buzzword such as fibre optic and apply a very general and extremely broad definition and concept of oepration to all it's standards and implimentations. in truth a sergical tubing a flashlight and a photostrobe/photovaltaic materical can be called fibreoptics in avery llose sense.
the protocal for TOS over fibre optic materical does not provide the bandwidth needed too carry uncompressed digital autio. the specification was set forth long before any uncompressed formats where made aviable to any consumers. outsid of AFF and WAV formats.
Second, the light used to send tos signals or any fibre optic based transmisisons greatly determins the amount of data that can be sent.
at anyrate. i'v attempting to supply information based on my limited knolege of the subject and it's implimentations. I am in no way responding based on having freshly read the standards from quoting from memory.
So if i'm wrong, please correct me. But please include proof.
Tim, your basically correct in what you say. Put simply optical is unable to handle the added bandwidth needed for the uncompressed audio The thing is that coaxial can handle the bandwidth so I do still believe that its also a copy write issue that someone decided to enforce upon us so we would be forced to use HDMI.
Onkyo 805, Yamaha YDP2006EQ, Samson Servo 600 amp
EV Sentry 500 monitors, 4 Mission 762i's Surrounds, Klipsch RC-52 Centre, SVS PB13U sub, Panasonic BDT220, Harmony 1100, Nintendo Wii
Panasonic PT-AE4000 on a 120" 2,35:1 fixed screen
tonyvdb, i agree completely withyoru accessment. the issues bieng pretty simple. if the companies pioneering these technologies don't push people into new standards then they don't continue to thrive and grow.
if optical or coaxual technologies where the end all of connecitons for digital multi channel audio. then HDMI would have never cought on. with with the concerns over piracy and HDMI's added security and copy protection measures. it insure thoes companies can and will continue to sell products.
forcing cunsumers into new formats and technologies is what drives th HT biz....
I have my DVD player connected to my Denon 3808CI via the optical out. Are you saying that I need to run the coaxial out in order to gain the benefits of dts digital surround for movies? Can I run both optical and coaxial and let the Denon decide?
Hopefully I can put this all together for you. This is my understanding.
FOR Optical or Coaxial both are part of a digital transport standard known as S/PDIF. This standard, as has been mentioned includes, both a physical layer and a link layer - If I can use network terminology. The physical layer is medium to sending the digital data. This is where electrons or photons carry the information across some kind of cable. Coaxial and Optical are both physical layer attributes. The "Link" layer is the protocol layer this is where the little bursts of light or voltage get translated into 1's and 0's. The chips(from various manufacturers) handling this translation were designed with the S/PDIF spec in mind which had a specific data rate for the standard. The standard was developed a long time ago when chip speed and cost were not what they are today - also the data rates needed then were very low. The data rate limitation of S/PDIF has it's root in the standard and affects the capability of the chip decoders in most of receivers of the last two decades. The physical layers (opt and coax) are potentially capable of much higher bandwidths but without a new standard no one is going to make a chip to try to push to the receiver mfrs and most importantly there wasn't a need for a higher data rate until now.
Along came HD audio content. Blu Ray and HD DVD both had high data rates. This is where the copyright issues come in. The movie industry(MPAA) and audio industry(RIAA) both have significant interest in protecting their Intellectual Property. Sony is a big player in both along with electronics and standards in general. In entertaining how to handle HD content they were already looking at a new video stand which did have copy protection built in (HDCP). It made much more business sense to build the newly needed audio standard into the copy protected scheme. It also simplified connections for consumers (well hopefully in the long run) One cable for all your hookups. Lossless and completely protected everyone wins they thought. Remember that Sony was one of the original developers of S/PDIF (Sony/Phillips) and likely could had pushed a different standard.
S/PDIF cannot carry HD audio because of a speed limitation. The speed limitation is in the decoders not the cables. Instead of implementing a faster S/PDIF standard the big companies added an HD audio capability to HDMI. HDMI can provide copyright protections (through HDCP) if the content provider wishes to use it.