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Extract audio from HDMI

post #1 of 32
Thread Starter 
My HD5450 graphics card will output 5.1 audio through an HDMI connector but my Rotel preamp will only accept toslink or coaxial connectors for digital audio.

I do have a spare HDMI port that isn't being used that is part of a splitter on my HDMI output.

Is there a device that can extract the audio from HDMI?

I've seen splitters and switches but I don't need to do that -- just take one HDMI and get one audio output is all I need. (rca or optical)

And no, my Motherboard does not have a digital audio output.


THANKS.
post #2 of 32

Look for an HDMI Audio De-Embedder.  Try Monoprice or Atlona or Geffen or.........................................................

post #3 of 32
Thread Starter 
Looks like price-wise, better to go with a $40 splitter that has dig audio outputs. I'll assume these will ouput dig audio for any of the HDMI inputs selected? (as long as audio is there, of course).
post #4 of 32
Thread Starter 
Ok -- already confusing.

No way I can do a $200 de-embedder and it looks like the splitter requires a 5.1 audio input !

So -- what other options I wonder?

An external USB to 5.1 card? Will it pick up all the 5.1 audio that is being sourced at the time?

like my Wintv card and DVD player?


THANKS
post #5 of 32
I have an external USB sound card that has optical out. Think I paid $40 like 6 years ago. I've never used the optical though so I can't comment on how it works.
post #6 of 32
Just use the optical out on your motherboard.
post #7 of 32
Quote:
Originally Posted by almostinsane View Post

Just use the optical out on your motherboard.
Didn't read the whole OP huh.
post #8 of 32

I would just buy a usb sound card that has an optical output. The Turtle Beach Audio Advantage Micro II is my recommendation, its $22 on Amazon. I was using this sound card with my laptop that output video through HDMI, very easy to setup and it works well. Bitstream 5.1 audio over optical and output video through HDMI.

post #9 of 32
Does your motherboard have a SPDIF header? If so you can connect a pair of wires to it & the other end to an RCA phono jack & this will give you coax digital audio. Check your mobo manual or look at the mobo for a 4 pin connector with 1 pin missing & hopefully it's labeled SPDIF.
post #10 of 32
Quote:
Originally Posted by ralphcramdon View Post

My HD5450 graphics card will output 5.1 audio through an HDMI connector but my Rotel preamp will only accept toslink or coaxial connectors for digital audio.
I do have a spare HDMI port that isn't being used that is part of a splitter on my HDMI output.
Is there a device that can extract the audio from HDMI?
I've seen splitters and switches but I don't need to do that -- just take one HDMI and get one audio output is all I need. (rca or optical)
And no, my Motherboard does not have a digital audio output.
THANKS.

This looks like what you want:

http://www.ebay.com/itm/HDMI-Audio-Extractor-Digital-to-Analog-L-R-RCA-or-Optical-Converter-De-Embedder-/370624842280?pt=US_Video_Cables_Adapters&hash=item564af64a28#ht_1495wt_1110



The hidden gotcha with HDMI is that the picture and the sound on a HDMI port is in synch (if the source is) but when you start bypassing HDMI, they can get out of synch. AVRs can only correct lip synch by delaying the audio, so if the audio is already delayed too much, you are screwed.
post #11 of 32
Quote:
Originally Posted by ralphcramdon View Post

Ok -- already confusing.
No way I can do a $200 de-embedder and it looks like the splitter requires a 5.1 audio input !
So -- what other options I wonder?
An external USB to 5.1 card? Will it pick up all the 5.1 audio that is being sourced at the time?
like my Wintv card and DVD player?
THANKS

1.  None of these "require a 5.1 audio input" but will handle any of the standard audio on HDMI.

2.  The Monoprice is $43.  http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10110&cs_id=1011002&p_id=5557&seq=1&format=2

post #12 of 32
Hey, I'm jumping into this thread with a similar situation. I have the SDPIF socket on my MOBO (see the picture). Can I take audio directly off this socket with some type of plug/cable combo, or is this designed for a sound card to be plugged in there? It looks exactly like the other PCI slots on the MOBO. THanks, I hope someone is still checking this thread SPDIF on MOBO 144k .JPG file
post #13 of 32
You don't have a SDPIF socket.

You have the PCB traces and a spot on the motherboard for a 3 pin socket to be soldered on.
post #14 of 32
Oh! Well then I guess it's back to the store to buy a sound card....
post #15 of 32
Quote:
Originally Posted by Francorosso View Post

Oh! Well then I guess it's back to the store to buy a sound card....

That looks like a SPDIF header connection without the connector. You said it looks like other PCI slots which is confusing. If there is a connector it should be only 3 pins sticking up. If there really is a connector all it takes is a small matching connector, a short piece of cable, & an RCA phono jack in order to get SPDIF coax output. That's what I did. Or if you feel confident you could carefully solder a jumper wire to the mobo itself. All it takes is a 2 conductor cable. One wire for ground & one for signal. The third pin should be 5 volts in order to supply power if you want an optical output, but you also need some circuitry for that.

They do make cheap ($10-$20) adapters that plug onto SPDIF headers, but you do need the 3 pins sticking up. Or again carefully solder to the mobo. You would have to check the mobo manual to determine which pins (or solder pads) are signal & ground because there is no standard. Or you could check with a volt meter.
post #16 of 32
I highly doubt that header is operational.
See those half white circles between the pci slots. That's for capacitors. The motherboard manufacture is most likely using one PCB to make a couple variations of the same motherboard.

I would check to see if SPDIF shows up in the playback devices before I break out the soldering iron.
post #17 of 32
Quote:
The third pin should be 5 volts in order to supply power if you want an optical output, but you also need some circuitry for that.

No, you don't need additional circuitry for optical out, you do need a small interface circuit for coax out though, preferably a transformer, or, at the very least, a voltage divider to reduce the voltage to SPDIF levels.
post #18 of 32
No additional circuitry is needed for coax out taken from the SPDIF header.

You need 5V for optical in order to power the circuitry to convert the voltage signal to an optical signal.

This link shows a coax & optical adapter you can buy that connects to the SPDIF header. It also shows how to connect coax to the header.
http://forum.videohelp.com/threads/333711-S-PDIF-connectors-and-making-your-own-MB-S-PDIF-connector

Here's a link right from our own forum.
http://www.avsforum.com/t/997533/howto-make-a-coax-spdif-output-bracket

Here's how to build an optical out.
http://www.mythtv.org/wiki/How_to_build_an_optical_SPDIF_bracket
post #19 of 32
Quote:
No additional circuitry is needed for coax out taken from the SPDIF header.

Yes, there is, as previously mentioned, you need a 500mV p-p signal, not 5V and you should have galvanic isolation.
Quote:
You need 5V for optical in order to power the circuitry to convert the voltage signal to an optical signal.

Correct! That's what the 5V supply is for, to power the red LED in the TOSLINK transmitter....but we're discussing coax, not optical.

Your links are not exactly an authority on this.

You might want to google a bit more, there's lot to learn.
post #20 of 32
I did a lot of searching on making a coax SPDIF bracket, which seems to be the terminology used if you wanted to buy one. Everything that I came across indicated all that was needed was to connect directly to the mobo header. I did search quite a bit because I did not want to damage the mobo.

I never saw anything mentioned that the header signal was 5V. Could you please point me to some more knowledgeable links so I can see what circuitry they recommend?

Thanks in advance.
post #21 of 32
http://www.epanorama.net/documents/audio/spdif.html

the TTL to coax circuits start about halfway down.
post #22 of 32
Thanks for the link.

I understand what you are saying. My previous searches were related to building an SPDIF bracket or words to that effect. Nowhere did 5V TTL ever show up. In fact here’s a commercial product which looks like an RCA jack directly connected to the coax. I guess there could be a couple resistors hidden in that plastic looking jack housing.
http://www.frontx.com/pro/p1062_030.html

Most of the commercial SPDIF brackets that I saw did have a small circuit board attached to the metal slot bracket. These all had both optical & coax SPDIF & I figured the circuitry was for the optical portion.

Since my last posting I did some more searching but this time for 5V TTL & SPDIF and came up with circuits similar to what you posted. Sometimes they mentioned converting the 2-pin CD-ROM drive audio to SPDIF. But I did not find anything mentioning that motherboard SPDIF headers were 5v or 0.5V.

I’m not trying to be argumentative. What are the chances that at least some mobos have a 0.5V signal on the header since the direct connection to the SPDIF works for the people who published the articles, & it works for me? If I’m overdriving the input on my A/V receiver by such a large amount shouldn’t I notice some kind of distortion?
post #23 of 32
Quote:
If I’m overdriving the input on my A/V receiver by such a large amount shouldn’t I notice some kind of distortion?

no, it's just a stream of serial data.
post #24 of 32
5V is used to drive the circuits of an optical digital port, 0.5v is the signal level found on a coaxial digital port. You DON'T use the 5V with the coaxial digital port or you'll most likely burn out circuits in your amplifier. A good post for building something like this is here http://www.avsforum.com/t/997533/howto-make-a-coax-spdif-output-bracket.

If you don't have spdif port on your MB, I'd just go with USB or PCI sound card. I'm actually using this sound card with my Raspberry PI and it works great! http://www.aliexpress.com/store/product/PCM2704-USB-DAC-USB-Power-fiber-optic-coaxial-analog-output-sz-11/813037_654055749.html?tracelog=back_to_detail_a

No case though, but I just mounted it on some plexi-glass which was a big deal because it's behind my stereo cabinet. Also it doesn't come with the USB cable so you need to factor that it. Otherwise you can get USB sound adapter like this one http://www.amazon.com/Syba-Digital-Optical-Output-SD-AUD20101/dp/B006SF68P2 for $12 that has SPDIF optical port and would do the job.

You don't need anything fancy because digital is digital and ultimately is the DAC in your stereo that handle the conversion from digital to analog.
post #25 of 32
Quote:
5V is used to drive the circuits of an optical digital port, 0.5v is the signal level found on a coaxial digital port.

...and 5V is the TTL signal voltage...which must be reduced to 500mV for the coax port.
Quote:
You DON'T use the 5V with the coaxial digital port

of course not, there's nowhere to connect it to.
post #26 of 32
That's interesting that ECS says my SPDIF voltage is OK but Gigabyte says theirs is not. I recall looking at several SPDIF brackets from ebay vendors & they all had 3 pin connectors because the brackets had both coax & optical outputs.

Obviously a manufacturer can do what that want, but I'd like to think there are some standards they would conform to. IOW how could all those vendors sell all those brackets without knowing if a mobo had 5V or 0.5V?

You have only a 2 pin SPDIF header & maybe that means something. As I mentioned above the only thing I saw about 5V TTL was in regards to 2 pin CR-ROM drives.This is just a thought but maybe 3 pin headers are 0.5V and 2 pin are 5V TTL.

The thread I referred to above does have links to some circuits for converting 5V to 0.5V. One was real simple using only 2 resistors. If you wanted to do a little soldering that might be something to try.
post #27 of 32
Hi I added coax outs to all my motherboards that had headers the only board that did not work was a gigabyte but I had an old optical bracket from a jetway motherboard,so once I worked out the pins both the optical in and out sockets worked fine.So it seems Gigabyte boards have a small voltage difference but it works fine with a powered bracket for optical out.
post #28 of 32
please help me with this extra 5v pin issue. i have bought asus oem spdif bracket, there is only coaxial in and out, no optical and there is 2x3 pin (2spdif in/out, 2 gnd, 1 5v, 1 key(emthy)). meanwhile my asus motherbord has 4 pin (1spdif out, 1gnd, 1 5v,1 key) . my question is should i wired up those 5v pin together. since there is small circuit at my spdif bracket, i will post the picture later. thankyou
post #29 of 32
this is what it is
post #30 of 32
I would try just connecting spdif and gnd from motherboard to the spdif in and gnd on the bracket thats all a homemade bracket needs.Looking at other thread dealing with a similar bracket it does not need 5v at all.
Edited by springmaker - 5/20/13 at 6:58am
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