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I have an HP 8740w with Nvidia Quadro FX 3800M video card. I connect SIIG displayport to HDMI adapter to the displayport. I connect a standard HDMI cable to the adapter with other end going to the T.V.

Video works fine but I can't hear audio out of the T.V. Speakers.

From what I've read, the video card needs to support audio via onboard sound on the VIDEO CARD or pass through from the SOUNDCARD (since it is coming out of the display port). When I look at the specs of my NVIDIA, it does not say anything about audio support whereas the 3800 (Desktop version of the vid card) does.

I am close to just accepting this is not possible (though in the back of my head I can't believe a $3000 laptop cannot do this and how HP could justify going from HDMI to displayport).

Here's where I'm at: running latest NVIDIA driver, running latest IDT drivers (for my sound) WIndows 7 64 bit, using SIIG Displayport to HDMI with AUdio ACtive Adapter (Says it supports: - Displayport 1.1 and HDMI spec - 2 channel stereo audio

Sony Bravia KDL46S-4100

I've tried: Put laptop to sleep Connected to T.V. Unsleep Check playback devices (no NVIDIA options is listed - though I can get the volume level for the "Digital Output Device (HDMI)" to flash with volume level.

CHeck NVIDIA control panel, notice that I have an audio settings page. From the I see: "Verify displays that will appear as audio devices in sound settings". My options are: - Display Port 1: empty dropdown box (when I click the down arrow, there are no options to choose) - Display Port 2: NO AUDIO CAPABLE DISPLAY AVAILABLE.

Note: I don't just want to connect to my headphone jack to get audio to my T.V. Help and thanks.

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I have never seen a DisplayPort to HDMI adapter before. I'm inclined to think it's electrically a DisplayPort to DVI adapter, with the DVI rewired to HDMI - this would explain the absence of the audio channel. (It would also mean they're lying, but I have no experience with SIIG myself so I can't make a judgment there.) I also am pretty sure this video card should support it, but not 100% there. – Shinrai Jan 3 '13 at 16:17

If this is the adapter you are talking about, then there IS an adapter capable of passing audio from the SIIG displayport to the HDMI cable. Not saying that is the one necessarily... just saying the specifications do mention audio and video... so it may very well BE the adapter you should purchase.

So, now the question becomes one of whether or not the Displayport on your laptop passes audio as well as video.

The specifications page for that model at HP doesn't mention audio as an option through the display port at all. This post, however, seems to indicate that it is possible... there are only a few short posts in the thread, and no links to back up what is claimed there, but they blame the adapter... which should not be the case as there are adapters out there which will pass audio. Now, from, there was a thread called the HP8740w owners lounge. In that thread, there is a posted solution... and it again has to do with the exact Displayport to HDMI adapter you use. I quote...

For those of you trying to get 5.1/7.1 Channel Audio out of the Display Port to HDMI when connected to your hometheater equipment, here is what i did/what you should do.

You need to get a DisplayPort to HDMI adapter that is a active adapter (usually the cheap ones are passive) and supports DisplayPort version 1.1a. Note that displayport v 1.1 doesn't support audio. I wasted 2 different adapters ($10 each) and then figured out all were passive. A active adapter is one that converts the Displayport signal into a HDMI signal (both audio and video uncompressed). A passive adapter is one that just passes the DisplayPort signal to HDMI without conversion (in this case only video goes out).

The author then goes on to provide a link to the adapter he said he purchased... but the link produces a PASSIVE adapter, which is odd after he had said you need to purchase an active adapter. At any rate, here is a link to the post within the thread.

To summarize... you need the right adapter.

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Thanks for helping out Bon. I like the that your response was thorough and well thought out. However, I've gone through 3 adapters, one passive, one active, one active with 2 channel audio support. I'm leaning towards NOT SUPPORTED. – user184275 Jan 4 '13 at 1:51
It may indeed not be supported. The thread I linked you to and quoted from dealt with an 8740w that had an ATI chipset as opposed to an NVidia chipset... which could make a difference here in the design HP followed. At any rate, HP doesn't officially state that what you want to do is supported. – Bon Gart Jan 4 '13 at 2:27

Okay, you can hook up an HP8740w via it's DISPLAYPORT to a T.V. HDMI port and get audio and video through the Displayport of the laptop.

Bon Gart gets the props for this one as I was about to give up. But you need a combination of things to get this to work.

  1. The trickiest part is getting the right adapter. I can only recommend this one: DisplayPort to HDMI Adapter CB-DP0062-S1 by SIIG


OR this one:

DisplayPort to HDMI with Audio Active Adapter CB-DP0L11-S1

From all the reading about choosing the right adapter, passive versus active, DP++ support audio pass though support, DP 1.1a support I would just say pick one that someones else says works! Don't look at a spec and say it the same as what worked for Joe. When I look at the specs of the ones I bought, there is little that tells one works and another won't.

So now the step by step:

  • I used the latest audio and display driver (from HP website).
  • Plug everything in and turn on laptop and T.V.
  • Right Click speaker icon and select playback devices. Ensure Digital Output Device (HDMI Out) is set as default playback device and default communication devices (may not need both but what the hell). Note, on mine it does not say plugged in, connected or anything (as other posts would indicate you should be looking for). Running WIndows 7 Pro 64 bit.
  • Play a movie

THings to check if it doesn't work:

  • NVIDIA Control panel | audio settings: mine shows displayport 1 = Sony T.V.
  • Playback devices: the Digital Output device settings should show levels bobbing up and down on the volume meter beside it. I turned off all enhancements, I checked 48Khz, DTS audio and Dolby as the supported formats (though most probably don't matter).
  • Turn off the laptop display (probably not needed but eliminates a variable if troubleshooting.
  • try restart and sleep.
  • Unplug adapter (while movie is playing) and plug back in (while movie is playing). This is what got to post the question in the first place. I tried for months with the correct adapter and it never worked. I was about to give up cause my video card said nothing about audio support. But Bon's post got me to try again. First with my Startech, then out of frustration I unplugged it and plugged in the SIIG while everything was running and sound came on (it was all distorted though). Then I rebooted and everything worked.

I think what had me giving up (originally) was bad timing of the quirkiness (you can have everything right but you need to reboot), being not sure which adapter would work and not setting my playback device to Digital Output device. (i.e. Good adapter, good device but quirkiness made me think it was the adapter, then change to bad adapter and of course it wouldn't work, tried the reboots with bad adapter and it wouldn't work (ironically the bad adapter was labelled DP2HDMI2 which led me to believe it supported the latest protocols) so I leaned towards using that adapater in my testing. The key is to get an adapter that someone else says works with their HP model (note getting their video card and sound card models is key if you want apples to apples), then you know from there it's about configuration and driver versions as I attest this does work.

Good luck to all.

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I am currently using this old 8540p laptop and also was facing this problem. After several hours of research the solution I've found was pretty simple - just need to downgrade the nvidia drivers. Here is the direct link to ftp server that helped me to get rid of this sound lack via DP+HDMI:

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