Help with HTPC audio

What's your audio system? TV usually supports only stereo via HDMI in.

What's your HTPC? Specifically the model of your graphics card. What's your TV? It depends on both the graphics card and the TV what audio formats are supported over HDMI. TV's analog in is stereo only (ususally).

If you are going to buy a high end sound system, it may be an HDMI (1.4a) AVR (or prepro+amp) + 7.1 speaker system. You would want to add a good graphics card with HDMI (1.4a) to your HTPC and connect it to AVR; then it would support multichannel LPCM as well as DD/DTS/TrueHD/DTS-HD audio bitstreams.

If the mb has an internal S/PDIF connector, then you can connect it to AVR or digital speakers using a bracket. Otherwise add a sound card with S/PDIF out. But you don't have any audio equipment that accepts S/PDIF now, and once you get a new AVR, you won't use outdated S/PDIF to connect HTPC to AVR anyway.

The current graphics cards use PCI Express 2.x that may have compatibility issues with your mb (PCI Express 1.x). If it works, then perhaps just adding a discrete graphics card (e.g. Radeon HD 5xxx) is enough now (stereo PCM over HDMI to TV) and in future (multichannel LPCM, DD/DTS/TrueHD/DTS-HD bitstreames over HDMI to AVR).

What is your definition of a high-end system?
For many people (audiophiles especially), high-end doesn't begin until you hit the $5000 mark and beyond. Everybody has a different price-point, mostly because everyone has a different aural range, not to mention spending capability. And some people (like me) can't differentiate or appreciate subtle differences in sound that are available in a higher-end system.


DVDs and BDs, both have 5.1/6.1/7.1 content. The audio quality doesn't depend on the number of channels; a stereo PCM audio track will have a higher quality than 5.1 DD/DTS. Online content, for the most part, is only in stereo.


One of the reasons users have an AVR is because it provides a centralized audio control center for all equipment. Any AVR will do a better job of simulating surround sound from a stereo source than a TV. It is easier to route all audio to the AVR. In fact doing it the other way will not work, since most TVs (that I know of) will not output over the SPDIF connection from any input except the tuner. Or if they do, it will be only in stereo.


As 'renethx' mentioned above, a TV has only two speakers, you cannot apply/give more than two channels to a TV if it only has two speakers. The OS will see those two speakers connected to the PC and will allow only two speakers to be set up in the OS (applies to Windows).


'Analog In' is, well 'Analog'; SPDIF is digital - two different things. The port is most likely 'Analog In' for that HDMI input and it would be stereo only.
Here's something for further reading about HD audio in a PC.

Forget the crappy TV speaker, pretend they aren't even there. Get a logitech remote if you think turning on the AVR is too much of a pain.

The AVR needs a direct connection to the PC for Dolby digital to work. TV's do not pass the DD signal, they down convert everything to 2.0 audio.

The logitech handles all the A/V switching with the press of a single button, switches the TV and AVR at the same time.

I never had medical quality sound in the hospital or docs office, so that sounds weird or as usual expensive or I think no such thing. You two need to decide the balance you want in audio or get separate systems. A basic hdmi 1.3 should suffice for now.

Most TV support only stereo PCM with HDMI IN, so *passing* audio HDMI IN to DIGITAL AUIDIO OUT is also stereo. If you watch HDTV programs, then DIGITAL AUIDIO OUT can output DD as well as stereo PCM.

Anyway if you buy a AVR, you won't connect the PC to TV directly. You will connect PC to AVR (via HDMI), then AVR to TV (via HDMI). This way, you will be able to use both a new sound system connected to AVR as well as TV speakers (AVR turned off, audio pass-through to TV).

The difference between HDMI 1.3 and 1.4. Notably HDMI 1.4 AVR supports HDMI 1.4a 3D video formats. You won't use it however.

You may want to spend a little more money for HD 5570/5670 (overall better video). There might be a compatibility issue of a graphics card PCI Express 2.x with the older mb supporting only PCI Express 1.x, however (upgrade your mb).

AVR's will pass HDMI signal even when turned off?

It may be called "Standby" (still 40W or so power consumption) that supports HDMI video/audio pass-through to the TV. To turn it off (i.e. 0W power consumption), the only way is perhaps unplug it off the wall.

You can buy graphics cards with HDMI that support carrying the audio as well as video. You just need to select the "video" card as your audio output device in the Sound Control panel.

One thought might be to use a graphics card with HDMI out (supporting both audio & video) to your tv, and then get a good sound card dedicated to sending audio to your music listening system. Then use somehting like Girder or EventGhost to switch the audio output device based on the application that you are using.

I think it would help if you better explained your room setup, the number of speakers you'd like to have, any other details, etc... I don't understand why you would need two AVRs. I'd probably keep my electronics to 20-30% of the budget and put the rest of the money into the speakers.

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Another option: find a sound card that supports output to both digital and analog at the same time. I think my X-meridian does this. Connect the digital out to your music AVR and then just run the analog out to your tv. This also solves the issue of switching between audio output devices.

Since this is my first post, I couldn't include a link. Search "anandtech adaptive vector." There's a worthwhile discussion of video cards. The 5450 would be sufficient, the 5570 better, and the 5670 ideal.

The entire discussion is interesting, so it might be worthwhile to follow the links back to the original review.

@cl0ud

HDMI audio solution by a sound card with HDMI is a waste of money. The ultimate purpose of digital audio is convey the information 100% faithful to the original source to the AVR, and this can be achieved easily by any cheap graphics card with HDMI audio (or any onboard audio S/PDIF for S/PDIF). The supported audio formats by HDMI and S/PDIF are:

- HDMI: multichannel LPCM, Dolby Digital, DTS, Dolby TrueHD, DTS-HD MA/HRA (not every HDMI audio solution supports all of them)
- S/PDIF: stereo PCM, Dolby Digital, DTS

Dolby Digital, DTS, DTS-HD HRA are lossy (i.e. part of the information is permanently lost in compression), while Dolby TrueHD, DTS-HD MA are lossless (i.e. contains all the information of the original source). If you are concerned with quality, you'd better avoid S/PDIF. The exception is stereo music (well the majority of music sources are stereo); S/PDIF is perfectly fine for this and onboard audio codec's S/PDIF is perfectly fine. (Nevertheless I don't see a reason to use S/PDIF.)

The HDMI audio formats supported by a graphic card is here.

A possible solution is:

- A graphics card with HDMI -> AVR (movies and music) & DVI (with a proper DVI-HDMI adapter for audio pass-through) -> TV (movies)

or

- A graphics card with HDMI -> TV (movies) & an analog sound card (e.g. ASUS Xonar Essence ST + Xonar H6) -> power amplifier (movies and music).

The former is simple and you will get good quality of audio in both movies and music via AVR. If you don't use AVR, you can still watch videos with TV. In the latter case, you use an analog sound card + amplifier for good music as well as movie. Here is a caveat: TrueHD/DTS-HD to LPCM is downsampled by a commercial BD player. A sound card with HDMI (Xonar HDAV1.3 and Auzen X-Fi HomeTheater HD are the only cards) without using HDMI is a solution to avoid it. Another caveat is that these cards are tied to a particular BD player (Xonar to TotalMedia Theatre, Auzen to PowerDVD). So you will lose freedom.

Stutter-free dual 1080p video stream via DXVA is possible with HD 5750 or higher. A DXVA stream + a non-DXVA stream is possible with any card (non-DXVA means you need a dual-core 2.5GHz or higher CPU). Dual HDMI audio stream is not supported by HD 5xxx.

Line out and Spdif are not the same. Line out is an analog preamplified output whereas the spdif is a digital multichannel output. I use the spdif into my receiver and can listen to BluRay in DTS or Dolby Digital and HDTV in Dolby Digital and it sounds great. Only the newer big budget BluRays have the new HD 7.1 soundtrack and many are still 5.1.

"Medical Quality" interconnects and speaker wire are unnecessary and a complete waste of money IMO. It's essentially just jewelry and provides no audible benefit no matter how expensive you gear is. It's marketing and hype so the store selling you the audio equipment can squeeze a few extra dollars from you. Often it leads to more than a few extra dollars. As long as you're using the proper spec cable and proper gauge wire then brand and cost don't matter.

I have a question about multichannel LPCM. I recently added a bluray drive to my HTPC. I have a Radeon HD 4550 and the drive came with Power DVD 8 for bluray playback.

I understand that the 4550 can't bitstream TrueHD/DTS-MA, but it should be able to send 8 channel PCM right?

All I can get is either 2 channel PCM or Dolby Digital/DTS bitstream.

How can I playback the TrueHD/DTS-MA track via PCM? Do I need different playback software? Is Power DVD 8 the problem Is there a setting I'm not seeing? Or do I have to live with it until I update my video card?

Yes, connect the HDMI port to AVR, then AVR to TV's HDMI IN 1 and the DVI port with this adapter to TV's HDMI IN2 (or DVI to AVR, HDMI to TV; does not matter). If you use AVR, watch (or don't watch) TV with HDMI IN 1. If you don't use AVR, watch TV with HDMI IN 2.

HD 5450 should be good, or go for HD 5670 if you can afford.

If the motherboard has an internal S/PDIF connector, you can connect it to AVR by this bracket. This might be helpful *in case* (this post) AVR can't recognize the graphics card when you turn off TV and listen to music.

Settings > Audio > Speaker environment: (Current system setting) HDMI, and Output mode: PCM decoded by PowerDVD.

Thanks, but I tried that and it was only sending 2 channels of audio to my receiver (Yamaha RX-V665).

When I set output mode to AC3/DTS pass-through it bitstreamed DTS to the receiver.

Perhaps it is the source material? It was The Hurt Locker. I can't try now, because I sent it back to Netflix. Won't have source material, until Tuesday.

Have you checked "Speaker configuration" of the sound control panel? If it is stereo, every multichannel LPCM audio stream is downmixed to stereo by Windows. Make sure it is 7.1 channel.

Thanks so much, I think that was the problem.

So that must mean the audio from my HDTV recordings were being outputted as bitstream, because I was still getting 6 channel audio from them as well as my DVD rips.

Thanks again, you are the best!

Edit: Ran out and bought a movie just to make sure, success!

Surely SPDIF signals can be transmitted through a 3.5mm stereo jack. Check the users manual of your system.

But why do want to use S/PDIF at all? Which audio equipment do you connect S/PDIF to?