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Discussion Starter · #1 ·
The Teranex Xantus has roughly 4 frames of delay at 60i. Depending on the source format it could be less.


How do you compensate for the audio sync?


1) Use built-in delay in your audio processor if it has such a feature?

2) Use 6 or more external analog delay units on your power amp feeds?

3) Is there an AC3 delay device made?

4) Use SDI/HDSDI embedded audio and let the Xantus delay the audio?

5) What audio delay?


I am curious of how HT users deal with this. In the commercial / broadcast enviornment we use external AES delay units.
 

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Im using the Lexicon and it has enough delay.


Teranex also offers a audio delay as an option.


Vigatec will shortly start shipping its audio delay box.
 

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Glimmie,


I know this one.


The Teranex platforms support embedded audio via SMPTE 272M or 299m on both of its players and the 3RU product has separate inputs for AES/EBU.


At SMPTE meeting last fall, a Teranex Rep (name escapes me) stated that all outputs have a "4 frame" delay except for a few exotic output resolutions which were only 3. He stated that the delay was going to be standardized to "4 frames" for every output resolution in the near future (probably implemented by now). Unfortunately, I assumed he meant 4 60Hz frames or ~67ms so I didn't ask him what exactly his definition of "frame" was.


Anyway, the important thing is the Teranex in all cases will delay the audio by the necessary amount. In fact, that is all it does with the audio. You only have to use external delay if you don't pass the audio through the machine. This is really only an issue with the 6RU version (if you don't have embedded audio) since on the 3RU's AES/EBU in/outs are easilly transcoded to S/PDIF via external adapters if necessary.


Extremely cool product. I unfortunately needed a 4:3 high def output so I really couldn't use it for a particular project. It would have been a very cool toy.


-Mr. Wigggles
 

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From what I know, the video delay on the Terranex is actually 7 fields (i.e., 3.5 frames).


That's 117ms on NTSC (!!), I didn't know that the Lexicon could go up that high.


In any case, this translates to 140ms (yikes!) on PAL sources.


The Vigatec sound delay box is supposed to be a fixed 4 field audio delay. If you wanted to use that, you'd have to link two of these units one after another.


From what I heard, the best solution is to use Terranex's own audio delay capabilties.
 

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Dear Ofer,


I really appreciate your knowledgable posts but where did you heard that

the VIGATEC delay box is fixed.


Here the actual features of the WAVE device:


3 optical inputs (AC-3/DTS 5.1)

3 coaxial inputs (AC-3/DTS 5.1)

1 analog input (stereo,converted to digital 2.0 using 24 Bit AD-converter)


1 coaxial output (AC-3/DTS 5.1)

1 optical ouput (AC-3/DTS 5.1)


- Adjustable delay up to 160 or 330 ms in 15 steps

- automatic input selection of the 7 inputs

- Reclocker for better sound with very low jitter at the output

- RS-232 controllable

- Integrated audio switching via DUNE-F with freely assignable audio inputs for 4 analog inputs and 6 digital inputs (altogether 10 inputs !!)


The unit is in manufacturing, please contact local dealer/distributors for

pricing and availability.
 

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Discussion Starter · #6 ·
Having serial number 1 since fall 1999 I know well what the Teranex can do. My question is how HT users deal with this issue. Embedded audio is not something a typical HT user will want to get into. Very expensive to put the mux's and demux's in a typical system where the decoded audio is analog (the six or more outputs from the processor). A simpler way would be to send the composite AC3 stream through on a single AES channel.


I think Alan answered the question. It seems most high end audio processors >$5K have intenal delay compensation. Surely somebody with a Teranex is not using a $400 Dennon receiver.


FYI, the Xantus also provides time code delay from VITC. Or like I do, you can use external timecode delay units. this is not an issue for HT use but very important in commercial use. Timecode is how we reference the 3/2 addition and deletion.
 

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Quote:
Originally posted by Glimmie
...Very expensive to put the mux's and demux's in a typical system where the decoded audio is analog (the six or more outputs from the processor). A simpler way would be to send the composite AC3 stream through on a single AES channel.

Sorry, I guess I wasn't completely clear when I mentioned S/PDIF to AES/EBU converters.


-Mr. Wigggles
 
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