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March 2013
Audiolics Anonymous Chapter 162
Home Theater Computer 3 (HTPC)
Learning from my previous mistakes.
Article By Bill Gaw
Over the past 10 years I've written several articles on using a computer as the main source for music and video production, storage and playback in a high end audio-video system. While Apple computers have had several advantages in the past including ease of use, better programs, and less kludginess, Windows based computers had the advantages of lower cost, more programs, and more variety of hardware.
I've attempted several times to build one from
scratch with the best parts available, to get the best build possible at the
least cost, but each time something has gone wrong and I've had to pay a
computer expert to correct my errors. In the end the HTPC cost more than it
would have if they'd done it first.
A: Audio
1. CD Transport with S/PDIF output (now also DVD, Blu-ray and HD-DVD playback)
2. 24-bit/96kHz A/D and D/A converters for internal digital encoding and decoding with transcoding up to 24-bit/ 96kHz. (now up to 24/384 and DSD decoding or transmission)
3. Recording of up to eight channels of analog with up to 24-bit/96kHz accuracy (now 24/384, 10 channels, and with pro cards infinite.)
4. S/PDIF input for decoding of external digital sources, including two-channel, Dolby Digital or DTS.
5. up to 8 balanced analog inputs with volume control, switching, D/A and A/D conversion.
6. up to 8 balanced analog outputs with volume control for up to 7.1 channels (with pro cards many more.)
7. Dolby Digital and DTS 5.1, 6.1, and 7.1 decoding. (Now also Dolby True HD and DTS Master Audio)
8. Dolby Pro Logic II decoding with 5.1, 6.1, or 7.1 output.
9. Mix up to eight channels of analog with 2 channels of digital into two channels.
10. CD-R,-RW recording (Now DVD and Blu-ray recording)
11. 10 band digital graphic equalizer (Now multi-channel graphic or parametric equalization plus speaker and room correction)
12. Storage of up to 200 gigabytes of audio or video information with almost infinite capacity possible with add-ons. (Now Terabytes)
13. Ability to decode DVD-A and possibly SACD in near future. (Now decoding of Blu-ray and DSD but still no playback or storage of SACD.)
14. Etc., etc. and yes etc.
B. Video
1. DVD decoding directly from the digital stream. (Now HDDVD and Blu-ray plus High Definition Video and Audio from the web)
2. Decoding of NTSC, PAL and High Definition off the air broadcasts (Now ATSC Digital)
3. Scaling of Video from 480i up to 1080p (Now up to the new 4K standard)
4. Increase of frame rate from 24 or 30 per second to maximum of 90 or 120.
5. Adjustment of Brightness, Contrast, Color, Tint, and Gamma of image before D/A conversion.
6. Recording of NTSC and High Definition signals to hard disc, tape, CD-R or -RW or DVD-R or -RW, or output through fire-wire or USB II to external video recorder. (Now decoding of Blu-ray, HD-DVD, web HD, output through HDMI)
7. Output RGBHV, Component, composite or S Video signals to Video Monitor. (Now DVI and HDMI).
8. Play video games in 2D or 3D.
9. Transfer Home digital or analog video tapes to MPEG II
encoding, store to hard disk, edit, and burn to DVD-R or-RW. (or
Blu-ray or hard drive or server)
The first article was way
back in January 2002 when I converted a decent Hewlett Packard computer
to audio and video playback through the use of semi-pro sound and video cards, a
DVD disc drive and the only available program for video playback, the original
PowerDVD XP.
In comparison, my last self-built home theater computer reviewed in July 2011 at this link consisted of a 3.2 GHz. CPU, 16 GB of RAM, three 2 TB hard drives for the storage of the massively increased music and video files obtained over the years, and the Windows 7 64 bit operating system. The motherboard's circuitry was insufficient to play back music files greater than 24/96 or Blu-ray videos over the motherboard's HDMI output, so it was necessary to add a XONAR HDAV 1.3 sound card and video card with HDMI output. While it was excellent and did everything necessary, a new HTPC was needed for my vacation house, and there were a couple of flaws.
1.The need for separate sound and video cards:
Audio can be transmitted in several ways to the music system.
1. FireWire, which while having high band widths, there are very few high-end audio products with a FireWire input.
2. S/PDIF, either optical, RCA, XLR or BNC which can only transmit up to 24/96 two channel audio with varying jitter rates.
3. USB preferably with asynchronous transmission to the preamp-processor for reduced jitter. While it can transmit up to 24/192, unless you use an external DAC with software for the computer that can do higher bit rates, that's again only two channel.
4. HDMI which can transmit up to 24/384 in up to 7.1 channels, but with the possibility for high jitter rates.
5. Analog output of multiple channels, the sound quality
depending on the sound card.
Video can be transmitted as:
1. RGB analog video.
2. Composite analog video.
3. DVI digital video only.
4. HDMI digital video plus audio.
2. Type of Video Card if needed:
Do not use a card with an NVIDIA chip. My last computer originally had one and using its HDMI output for video and multi-channel audio transmission, its' software didn't allow for transmission of 88 or 176 kHz bit rates. Two channel could be done through the S/PDIF or USB outputs but HDMI output had to be converted to 48 or 96 kHz which cannot be done perfectly.
After days of trying to find out why this could not be accomplished as video card manufacturers don't mention their audio transmission rates, I reiterate that NVIDIA chips and software don't allow for bit perfect 88 or 176 kHz transmission. So make sure you get a video card with an ATI Radeon chip which will at least transmit 16 bit, 88 and 176 kHz audio for external processing.
Happily, as of the latest Intel Core i5 or i7 chip sets with HD Graphics 4000, with compatible motherboard, and Realtek ALC 898 audio drivers, they now have the power to support directly from the motherboard's HDMI output 1080P video plus up to 7.1 channel 24/192 audio without problem. In addition, with the Realtek ALC 898 drivers, both 88 and 176 kHz digital can be output bit perfect. This obviates the need for both a sound and video card which cuts down on complexity and the need to transmit the digital signal through multiple extra connectors, chips, wiring, etc.
Learning from my previous mistakes, this time I went up on the web and found several small companies based in the US that will build a computer to spec, and for a price that is equal to or less than what it would cost if one purchased the individual parts themselves. The company chosen was Ly Computers of Suwanee, Ga. Through several email exchanges, I listed the parts I wanted and why, and they returned with various other parts that would be possible. Through negotiation and discussion of what I was looking for in performance, the final parts list consisted of:
1. Silverstone Lascala LC17-S Silver case (horizontal style, well constructed with plenty of room).
2. Intel i7 3770-K Cpu which can control an HDMI output (it must be a K chip to do the functions necessary) .
3. MSI z77A-GD80 motherboard with HDMI, USB, and S/PDIF output on the board.
4. Kingston DDR3-1600 16GB Ram
5. OCZ OCT125 SAT3 256GB SSD for the boot drive for speed and accuracy.
6. AMD Radeon HD 7970 video card.
7. 1000w power supply to support multiple hard drives.
8. Windows 7 home premium 64-bit.
You'll notice that I added the Radeon video card even though I'll be using the motherboard's HDMI output with its lower jitter for audio. The video card is being used in Virtu-I mode, an Intel system that allows the usage of the video card's RAM by the motherboard when high bit rate video is running, but allows the low jitter output of the motherboard for high bit rate audio with/without video, the best of both worlds. The system automatically determines when the motherboard's CPU in insufficient and adds the video card's memory which only occurs with high bit rate video. Thus, when listening to high bit rate audio files, only the motherboard is used, thus again decreasing jitter.
You may also note that no hard drives were involved in the
purchase. That's because all of my audio and video files are already loaded onto
three 3 TB hard drives which were easily installed here.
1. MediaCenter 18, jriver.com/download.html
for playback of all audio and video files and web radio stations, the Swiss Army
Knife of programs; $49.95
2. AnyDVD HD, slysoft.com/en/anydvdhd.html for
transcribing DVD and Blu-ray discs to the hard drives for improved low jitter
playback, $59.95
3. JPLAY, jplay.eu
for playback of stereo files through RAM loading for minimal jitter $99.95
4. TotalRecorder Pro, totalrecorder.com/productfr_trPRO.htm for
bit perfect recording of web radio broadcasts, mainly Boston Symphony live
concerts $36.95
5. iTVMediaplayer, itvmediaplayer.com
to obtain several thousand television and radio stations. (Goodbye Directv and cable!)
So how does the unit sound and look? Phenomenal!
This is one of the best investments I've made in audio, with excellent video to
boot. The unit is connected by HDMI and S/PDIF directly to my Classé CT-SSP
pre-pro, and by USB asynchronously through my OPPO BDP-105 Universal Player to
the system.
The biggest improvement has been with the HDMI output of
Blu-ray classical music concert discs. Previously, they had sounded as if their
ambiance retrieval was minimal, but now the hall's effect has solidified on the
best. That alone was well worth the cost. With the addition of being able to
store all of my audio and video internally on three 3 TB drives, obviating the
need for external units, I now only have to get up once from my listening chair
to turn on the computer's on button. Then my entire collection of audio, video,
and just about every radio and television station in the world is available by a
motion of my portable keyboard-mouse in up to pristine high definition audio and
video. The audio and video comes close to or surpasses any sources available at
present somewhat under the mega-bucks range.
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