DIY home cinema running on a PC?

dave502619

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Hi, I am a software engineer looking to build my own multi channel home cinema. I am currently writing the software to run on a PC and intend to have a number of HD digital sound channel buffers to output. I am trying to determine the best path to take to get this data converted and amplifed to my speakers.

I believe a standard sound card would perform the DAC conversion and then amplifier the signal and combine the channels into the 3 stereo pairs. But i suspect this configuration would not be good enough quality DAC and amplification as my current home cinema setup? - i have a Onkyo SR608 amp with KEF900,500c speakers.

I imagine what I am looking for is a type of card inside my PC to which i can write the sound data my
software produces and output to individual channels. Ideally the DAC will have been done by the card and the analogue outputs will just need to be amplified? Or maybe there are other options to
achieve this goal where the DAC and amplification are done outside the PC? I am aware of the SPDIF however the bandwidth will not be compatible with HD sound i have read? I intend in future to be able to support many individual channels for future formats , eg. 16.

Thanks
 
I was under the impression with HDMI i might be limited to 8 uncompressed channels? so would get complicated having to write to two HDMI outputs in the future for more channels.
 
I don't know the details at the level you're working to, but I was just thinking that the current formats with HDMI such as Dolby Atmos and DTS:X will support 7.1.4 or 9.1.2 IIRC, with more channels being added in the future so might be more useful, and any future increases to that will be either supported within HDMI or Display Port, though I suspect that DP may not end up as a normal consumer option.

Gary.
 
I think he is right about HDMI allowing 8 discreet channels only but that is discreet channels and uncompressed.

Maximum audio throughput seems to be 36Mbit/sec across the board even on HDMI 2.0 so those Atmos channels must be using some magic trick to achieve that sort of quality.

HDMI - Wikipedia, the free encyclopedia
 
You have two choices for audio. Either an onboard multichannel DAC, or external USB multichannel DAC.

The mainstay of these devices are in pro-audio for multitrack input and output, from RME, Lynx or Antelope.

The only external USB multichannel DAC I know for "end-user" is the exaSound e28.

Softwarewise, your main issue is decoding. At present, DTS and Dolby have only released the DTS HDMA and Dolby THD codecs a few years ago. Decoding of 3D audio on PC is not possible yet, if ever.

You can write your own code, or just use Jriver which has been in development over many years.

Then there is EQ software. The 3 main ones are Dirac, Acourate and something else (can't remember). Mattkhan is the best source of info on this forum (and then some).

Outputting to HDMI is of little gain. You will still rely an external pre/pro or AVR to do the decoding. You can of course decode and EQ on PC, then output as LPCM. But you're still hampered by the DAC on the external pre/pro/AVR. And suffer from all the jitter of HDMI. On balance, less headache to just let the pre/pro do everything. Use CCCP and windows media player classic to bitstream via HDMI.

Since you already have an Onkyo and speakers, the latter option is the easiest. Don't need to be Bill Gates to setup. Everything open source. Most present day motherboards or graphic cards have HDMI output. That's all you need. Don't even need a soundcard.
 
Thanks - there is a lot of new areas I can look into now from what you've written. The exaSound e28 looks great but its a bit pricey for me. I am going to look around the other manufacturers you mention...

As a bit of background to my issue - on my Onkyo I am running movies in Audyssey DSX mode and i really like the 'wide' option it creates. Correct me if i am wrong but it appears as i'm using two channels for the left and right wide's i then loose two of my rear channels. I also cannot have both 'wide' and 'height' as I guess a 7 channel amp you are limited to that number of channels.

Therefore my idea for building my own home cinema system is i can have as many channels as I
like, so lets say 7.1 discrete channels plus maybe 2 wide and 2 height channels. The wide and height channels i believe are subtracted from other channels by the Audyssey algorithim - so i would have to be doing that in my own code but thats a further issue.

As well as increasing channel numbers i could also improve amplification after the DAC, I could experiment with different power to my speakers, although i am unsure if increasing above what my Onkyo outputs will make it actually sound any better?

I have been working my way through the "windows media player classic - home cinema" code for a couple of weeks and my plan was to tap into the audio streams from there to 'divert' them out to my own code i write. Once i have these channels I can process them further as i please with whatever algorithims i like.

At the moment I am just thinking of DTS-HD master audio and True HD sound formats for of
course in the future I would need to re-address everything for the new 3d formats - but by then
I will have a good knowledge base to build upon. But whatever format i used would all be done by my software and the output from the PC would just be a number of sound channels and the sound format has been resolved earlier in my code.

As regards output to HDMI then to my Onkyo i will then be restricted again to 7? channels of output. I was hoping move away from HDMI as on output from the PC i then have limited options
to connect freely to other kit.
 
I use jRiver bitstream and found it to be fantastic especially when it comes to options it offers tons I don't see a reason to get anymore complicated than that it really is comprehensive.
 
Thanks - there is a lot of new areas I can look into now from what you've written. The exaSound e28 looks great but its a bit pricey for me. I am going to look around the other manufacturers you mention...

As a bit of background to my issue - on my Onkyo I am running movies in Audyssey DSX mode and i really like the 'wide' option it creates. Correct me if i am wrong but it appears as i'm using two channels for the left and right wide's i then loose two of my rear channels. I also cannot have both 'wide' and 'height' as I guess a 7 channel amp you are limited to that number of channels.

Therefore my idea for building my own home cinema system is i can have as many channels as I
like, so lets say 7.1 discrete channels plus maybe 2 wide and 2 height channels. The wide and height channels i believe are subtracted from other channels by the Audyssey algorithim - so i would have to be doing that in my own code but thats a further issue.

As well as increasing channel numbers i could also improve amplification after the DAC, I could experiment with different power to my speakers, although i am unsure if increasing above what my Onkyo outputs will make it actually sound any better?

I have been working my way through the "windows media player classic - home cinema" code for a couple of weeks and my plan was to tap into the audio streams from there to 'divert' them out to my own code i write. Once i have these channels I can process them further as i please with whatever algorithims i like.

At the moment I am just thinking of DTS-HD master audio and True HD sound formats for of
course in the future I would need to re-address everything for the new 3d formats - but by then
I will have a good knowledge base to build upon. But whatever format i used would all be done by my software and the output from the PC would just be a number of sound channels and the sound format has been resolved earlier in my code.

As regards output to HDMI then to my Onkyo i will then be restricted again to 7? channels of output. I was hoping move away from HDMI as on output from the PC i then have limited options
to connect freely to other kit.

Ok Dave. Let's take a step back and reexamine what issues you are currently having.

A more immersive sound environment is not just about having more speakers. Existing sound formats have been established over the years as what generally works. ie 5/7.1; DTS:X and Dolby Atmos. IMAX made the same point. they refuse to go down the Atmos route.

There are many reasons why you may have problems with your setup. Can be anything from speaker matching, room setup, weak amplification etc. Throwing more speakers aren't necessarily the answer. Our ears don't work like that.

Those of us who have gone for the hardcore HTPC route do so after careful consideration of what off-the-shelf pre/pros can offer and the limitations of using a PC. There are many on the forums that used to run PCs that have switched to outboard pre/pros/AVRs.

From what you have described, I do not see any issues which require a PC to fix. If you're after 3D audio, you're better off investing in one of the 3D Audio AVRs which have DTS:X, Dolby Atmos and Auro 3D and use their proprietory upmixing for non 3D content. You can still bitstream using Windows Media Player and HDMI output.
 
I take your point about throwing speakers at an issue or maybe just increasing power and thinking it will sort everything is the wrong way. However i've identified that the Audyessey wide channels are really making an improvement for me, but the loss of the two rear channels because of it is also leaving a definite gap behind my seating position. So suddenly my 7 channel amp is not enough.

I'm just thinking this all through and your feedback is really excellent help, what i imagine is that if you take the HTPC route then you ideally want the software to resolve everything (ie. decoding of the format, room eq etc) and you only output pure PCM channels. Then what you want for your off the shelf hardware is a soft of 'dumb' item(s) that receive PCM for 'x' number of channels and does the DAC and amplificiation but is not aware of True HD or Atmos etc. ie, having the pre/pro do the decoding of the 'current' formats means you have to replace it every few years - having spent all that money on decent hardware. Whereas if everything is resolved in the software you don't have to replace hardware so often so you can buy really decent kit you know will last. Like your speakers.
So i guess this is why i am looking towards the HTPC route.

I suppose off the shelf pre/pros are quicker out on the market for the new sound formats and the HTPC route lags behind?
 
You got the point exactly. Pre/pros do decoding, DSP, D/A conversion, and in AVRs, amplification.

The big bug-bear, and many people were stung 5-6 years ago with the introduction of HDMI, is as you say, format changes.

One of the most powerful pre/pros available uses an i3 processor (Trinnov). Its the DSP which is most processor hungry.

But DACs and amp technology remain fairly static. So its a waste to change everything every few years.

The DACs are pretty limited too. Hence I went for the HTPC route. An intel Core processor can do better DSP than any DSP chip. The e28 uses top grade Sabre DACs with ridiculous SNRs. A topline pre/pro like Classe, Datasat or Trinnov will easily set you back 5 figures.

The issue is decoding. PCs depend on the source codes to be released. Even TrueHD and DTS HDMA only came out a few years ago. No sign of DTS:X or Atmos coming out soon. At any rate, other than Pro Audio DACs, there aren't any USB DACs with more than 8 channels at the moment

But again, while the heights are definitely helpful in your setup, it may be just that your setup needs the help of height channels. Surround audio is more than just channels. The original stereo format uses 3 front speakers only.

My suggestion is go listen to a good 5.1 setup and see if its really height channels you need.
 
Yes I would also suggest to try Atmos in 7.2.4 or 7.1.4 with a good sub, I have the best HTPC (i7 6700K)money can buy hardware and software wise and I found that the Onkyo 3030 with its 11.1 channels is truly immersive when running Atmos it really does make a big difference and I do not feel the need to upgrade any time soon the first time in a long while.
 
I bet that Onkyo 3030 sounds great - have you got embedded speakers in the ceiling for the Atmos (2 or 4?) or using those ones which fire the sound up and it bounces back? Are you getting definate directional sound from above or is it more of a overall surround effect?

Theres a couple of things about the HTPC route i've heard so far that could be an issue for me - one is that there are only 8 channel external USB DACS available. My idea was to make a modular system where i start with 5 or 7 channels and then add channels as i require them. I need to troll through the websites recommended by (lokyc) - RME, Lynx or Antelope websites and see if any internal card is available. I take it that the 8th channel would be used up by the .1 subwoofer output.

The other issue is the format delay - sounds like it could be years before Atmos/DTS-X etc are available for HTPC.

On a separate issue two of the best areas of my home cinema are having connected the centre speaker to my sub-woofer via the high level cable - adds so much cinematic depth to the dialogue Secondly the addition of a butt-kicker LFE adds such an extra dimension- obviously explosions etc. are great but you also get very subtle effects that add to the drama. I really notice a loss if either of these are not present.
 
Well yes the 3030 is so good that I am not upgrading to a DTS:X compatible AVR I just love the sound signature so much and the convenience of having full 11 channels plus its very sweet musically. Definite directional sound yes form the up-firing but that is long story and needs very careful setup see my posts here:

Bit underwhelmed with Atmos

As for the bass I went for this sub so I don't need a butt kicker it just does it for me even when i hear no bass sometimes: MartinLogan BalancedForce® Subs, Flagship Subwoofer Series

Good idea on connecting them center channel I may try that.
 
Can anyone help - i am new to MPC-HC and i want to play blu ray discs. I am trying to select the drive or files within folders on the disc drive from within MPC-HC but it won't recognise any files/folders. I have used MakeMKV to copy the disc to my HD but same issue when selecting the files/folders to play.

I have tried some blu ray ripping software but the files when ripped are massively smaller and the sound channels not all present, eg. 5.1 instead of 7.1.

In summary i want to play my blu-ray's via MPC-HC without loosing any video/sound quality.
 
You my want to post in the correct location not hijacking a different thread friend.
 
The pro audio interfaces are where you need to go for >8 channels. have a look at MOTU or Beringer and the like. they usually have Asia drivers and expansion options via adapt as well as inputs should you need them.
 

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