View Full Version : SDI Audio - is it not embedded!!??

01-26-2004, 05:22 AM

i just bought sdi card for vt3.
i use sony DVWA500 digital video recorder.
altought it is high end recorder, i can't use it to record/digitize sound thought Newtek SDI for VT3!
audio is not embedded (multiplexed) in SDI video in/out!!!!

of course, we can say that maybe it is in SDI digital audio in/out in card, but... if it is not embedded in video also, it makes it not usable (without another expensive equipment, which can costs to 2500 $!!!!)

in digital video recorders i'v seen, you HAVE NOT separate digital audio IN/OUT. there is only digital video (audio transfers thought the same, one cable)


01-26-2004, 08:50 AM
The Sony DVW's have AES IN/OUT and can be directly connected to the SDI card with no other equipment needed. That is how we have it. I have never taken a survey, but most facilities have full Digital Routers that route 601 SDI and AES/EBU as standard operating procedure. That's not to say embedded AES doesn't have it uses and advantages.

01-26-2004, 09:33 AM
Thanx for suggestion!

Yeah, digital videorecorder has AES IN/OUTs.
I'am not advanced specialist in technology, but it is great if it's so simple!
Then, is that means, that I can use digital audio from SDI and just put it to AES IN/OUTs?
Still I need any conversion then, I'am right? SDI audio is just one BNC cable, but AES audio needs 6 connections (2 symetric).
I need to buy Digital Routers that route 601 SDI and AES/EBU?
How much could it costs?

thanx a lot

01-26-2004, 02:50 PM
Your SDI card should have two AES Audio connectors. On for in and one for out. AES is always in pairs, so each is stereo signal. The connector is BNC and most likely any AES cable you run from a deck will look like a Balanced Audio Connector. You can buy or wire an adapter to go from Balanced to BNC. My engineer here wired ours and I could ask him about it but I think that info is readily available.

Edit: Re-read your post above. You would not use SDI Video cable for the AES, you would use the dedicated AES Audio connectors on the Deck to the SDI option board's AES audio connectors.

01-26-2004, 05:07 PM
I am not an Audio Engineer so check with your engineer first, but I believe something like one of these (XLR Male and Female needed):

Canare XLR To BNC Impedance Transformer (http://www.markertek.com/MTStore/product.CFM?BaseItem=BCJ%2DXJ%2DTR)

Neutrik AES/EBU Digital Audio Impedance Transformer (http://www.markertek.com/MTStore/product.CFM?BaseItem=NA%2DBF)

01-26-2004, 08:48 PM
You are impresive!

I must say that it's great to know, that there is so helpful person (like you) around.
I see, that my knowledge is poor in comparision to your, but count on me in any help I can do.
I have two VT3 sp2, one with SDI, another without, based on dual opteron system on tyan thunder motherboard.

[email protected]

Good luck!

01-26-2004, 09:32 PM
No person can know everything in this business, but it's amazing, how collectively we do!:)
Every day I learn more then the day before, by reading these forums. They're Great!
Thanks Brad for the info.

01-26-2004, 11:21 PM

Hopefully you will get you AES working quickly. We have never actually had the output work for us and we are having it repaired by Newtek tomorrow, hopefully. The are here in San Antonio, so they are just a couple of miles away.

One note about the input. There is a setting in the Preferences you need to enable that allows AES input when SDI is selected on the Switcher during capture. The AES audio does not come through the Audio Mixer module. It can not even be monitored or listened to except while you are capturing.

As with the rest of VT3, the current audio levels seem to be off, or a least for us, low. I crank the input on the Capture panel fully on most of my captures and that gives me good level. If your source is a little hot you may have to back it off, because once you hit the top of the head-room, you will get serious distortion that can not be removed.

Ted, I agree completely with you. For example, I know very little about all the DV and DVD issues but because so many here do, I feel I've got that covered if needed by this great community and the archives!

03-21-2004, 03:58 AM
:( help! i need to know how to make the conection !

VT use digital audio i/o BNC connectors

but we are using BETACAM DIGITAL decks

what i must do to connect VT to DIGIBETA ?


03-21-2004, 10:50 AM
That is described above. You will need a pair of the Canare's to transform signal (110 to 75 ohms) and connector (XLR to BNC) in and out. It was recently reported to keep the BNC cable as short as possible, to avoid interference and other problems.

Some have reported success with this connection directly to Digibeta, but we have, for some reason, found that we had to convert the 44.1 kHz VT3 output, as measured on our Tektronix 764 Digital Audio Scope, to 48 khz output with a Zsys Z-Link. YMMV.

Operational Notes: [list=1] AES output is always active AES input is only active when 'capturing' Preferences must be set to "Use SDI Audio" SDI input must be selected on switcher for AES input AES input can not be monitored or adjusted through the Audio Mixer (but I think input mute is effective)[/list=1]

01-25-2005, 11:27 AM
i need to install a VT4 card in a TV studio with audio embedded (multiplexed) in SDI video in/out.

ALL the studio 's audio is embedded (multiplexed) in SDI video in/out !!

how can i use it ?

tkx in advance

01-25-2005, 12:06 PM
Well I've done this but I would suggest doing some tests...

There is a fix to the AES giving out the wrong header info...

1) I would touch base with NT and make certain that you have the newer modified SDI card...

2) I would suggest that you get a Muxer...

Check out Lynx

this 3000 mini module
P MX 3212 B - Dual AES Audio Multiplexer

Since the VT uses 75 Ohm BNC connections....otherwise use a transformer to convert to XLR..if that is what your muxer has....


1) VT can push black below 0 Ire....you must keep EVERYTHING Above this or it may cause intermitent loss of audio or ocillations.

2) Must make certain that you work with ONLY one standart...PAL or NTSC...
If you are working with PAL...then you MUST not have any sources on the VT switcher that are not connected...(due to them going to NTSC black)...if you mix standards this will also effect your audio...

3) keep from using any DV sources...there is some sync issues that cause audio issues loss and ocillations.

If you need more help drop me a private email off list.

[email protected]

Are you also needing to go over fiber?


Paul Lara
01-25-2005, 01:31 PM
how can i use it ?

There is a mux/demux device offered by
Convergent Design (http://www.convergent-design.com/ ) .

01-26-2005, 03:22 AM
That's a nice unit Paul...thou the Lynx mini modules should cost less and take up less space...or check out AJA....but Lynx is the best for the money IMHO.