First would like to thank everyone for the help on my HTPC.

I posted back in May on the System Advice forum a proposed parts list for a HTPC based upon my research.

http://www.silentpcreview.com/forums/viewtopic.php?t=40112&highlight=

You all almost completely changed my proposed list (I only kept the case and memory), based upon solid reasoning.

I finally ended up with:
Case - Silverstone LaScala LC-20M
MB - Asus M2NPV-VM -- mATX / AM2 / nForce 6150 + nForce 430
CPU - AMD Athlon 64 3500+ Lima 2.4GHz 512KB L2 Cache Socket AM2 Processor ADD3500CNBOX
Western Digital Scorpio WD1200BEVS 120GB
2 gigabytes DDR2 Memory
CPU cooler - Thermalright ultra 90A
PSU Seasonic S12 430Watt
Generic DVD CD Player
Case Fans – 2 x PCExtreme 250mm 12 VDC Fan
Gyration Cordless Keyboard
Gyration Cordless Air Mouse

The project must be described as a complete success, fan noise – gone!, disk noise – Gone!

The Full Rig is Shown Below.


The 80 inch HDTV is a rear projection CRT, a veteran purchased in 2001. Still works well, Windows Media player is on.

The next pictures show the 250mm fans as they are implemented on the cabinet.

Why and how can I use such big fans? I have a large 1500 watt HT Receiver (Yamaha RX-Z9) in the equipment cabinet and this unit must be ventilated. This is the main source of cabinet heat, its power supply is a huge analog unit that’s not very efficient. This cabinet was purchased when I purchased the HDTV. This cabinet is part of a large decorative piece of mahogany furniture that surrounds the TV. My wife informed me that equipment out in the open, spread around the room was not possible so the cabinet is non-negotiable. So the problems are, the decorative cabinet must be used and the cabinet must be ventilated even without the HTPC. It seems that using the cabinet fans to also ventilate the HTPC is an efficient solution and likely much quieter.

This picture shows the parts of the ventilation system for the cabinet.



I put the big fans in the back of the equipment cabinet and baffled the cabinet to force the air flow, facilitating the cooling of the HT Receiver, other equipment and the HTPC with these big fans. The fans mount in a plenum on the rear cabinet cover. The rear of the HTPC is butted up to the front of the plenum and sealed with weather stripping.

This picture shows the HTPC butted up to the plenum as it will be in the cabinet.



The PC has all of the expansion slot covers and both 80mm case fans removed to open up the rear of the HTPC reducing air flow restriction. The PSU has a fan and its air flow comes in from the side of the case and out the back, so it’s not in conflict with the big 250mm fans, though as far as I can determine this fan never comes on when playing music. The PC uses fairly low power (thanks in large part to this forum’s recommendations) so presumably the power supply is idling mostly. The air flows in from the bottom of the cabinet over the top of the receiver, then up over the other equipment and then finally through the HTPC and then vents out through the fans.



With the glass equipment cabinet front door closed there is literally no sound from the rig. If you put your ear in back of the cabinet you can just hear the fans and very faintly an occasional click from the hard drive emanating from the fans. This is with the furnace, refrigerators and clocks off and no sound playing from the system.

I’ve posted a more detailed description of the ventilation system in the Fans and Control forum (Two 250mm Fans Cool HTPC and Entire Home Theater). I took fairly extensive air flow and temperature measurements to make sure the fans were doing the job.

thats a big TV....a really really really big TV.

i have an old Sony receiver, but not nearly such a focused system [i've got speakers all around my room].

how good is the wireless KB/M set? mine is alright, but looses its signal easily.

a 1500W receiver! i work with mackie and crown amps that barely push 1300...thats nuts!

with just the two fans, and the CPU cooler, whats the CPU temp?

whats it like with such strange screen resolution [the fuzziness]?

if you want really good compatibility with audio, you should look into the M-Audio Audiophile 24/96..i recently got one, and sound quality is amazing, and it uses RCA in/out, so with a receiver you don't have to bother with anything but RCA.

What's KB/M?

The 1500W receiver is Yamaha RX-Z9 9.1 with 6 surround speakers, its top of the line and great. It upconverts all video to 1080i as the old HDTV will sync on only 1080i on the high def input. Old VCR video tapes even look a bit better.

Strange screen resolution [the fuzziness] Windows Media Player is running on the HTPC. The screen is dislpaying the music Spectrum in blue). This HDTV is actually quite good in resolution. I just had it calibrated and its sharp and the text is clear. Perhaps the screen looks fuzzy because you are seeing the reflection of the camera flash.

See the post in Fans and Controls for a complete description of the tempature and performance of the cooling system.

http://www.silentpcreview.com/forums/viewtopic.php?t=42580

I'll look at the M-Audio Audiophile 24/96. The Asus Motherboard has built in 1080i and audio using the NVIDIA chip set. Its supposed to be fairly good, but I'm new to HTPC. Do you think its better? I don't need surround sound decoding as the Yamaha does this. All I need is a good quality bit streem from the HTPC.

Sorry for the off topic remark, but did anyone else get a "spyware cleaner" popup when clicking on those pictures?

Very nice setup btw.

Yep. Me too! Highly irritating! Mental note has been made to never ever use "spyware cleaner". There is such a thing as bad publicity.

Gosh

I hope the spyware problem is not associated with my pictures. They came off of my digital camera. Titles were added by Abode Illustrator. Then they were immediately uploaded to imagevenue.com. I don't have a spyware problem on my computer and have not for some time. Last I had such a problem (last year) I had to format and reload all my software. Luckily I keep all my personal data on separate drives so I did not lose anything.

I’ve used imagevenue.com before with no problem, however, if you all have been getting spyware problems from them I will never use them again.

with onboard audio you can turn it up enough and get the strange background fuzz, i haven't gotten that with my M-Audio...as long as you don't push it way too far, it stays clear...just limit its output and use the receiver to amp it more. you'll definitely notice a difference in sound with such a large system. just don't run your inputs through TV, Tape or Phono, you wont get the surround sound. CD is the best for running an input. you can get RCA crossovers if you need it to have the CD input shared.

M-Audio is normally an expensive and high quality studio type card, but with a surround system, even if you don't record, its not a waste at all.

I found the S/N spec for the Intel MB sound. It's listed as 95db. The M-Audio board is listed as 106 db. This is a big difference. They probably do a better job of isolating switching PS noise and digital bleed through from the bus getting into the audio bit stream. The only worry is that the M Audio Audiophile unit doesn't have an optical link for the audio bit stream. The optical link assures that no ground loops can degrade the bit stream. But none-the-less the noise spec is what it is.

Perhaps this is all getting carried away, but after spending this much money one must make sure all bets are covered. I think I need to give this a try. Since I don't use this HTPC to play movies and only music with Windows Media Player I probably don't need to obsess about the quality of the video produced by the MB.

By the way, on this matter, I have an up-converting DVD player that puts all DVD’s at 1080i resolution that ignores pesky copy protection. You are probably aware that DVD players will down convert CP DVD’s to 480i if they do not handshake with an “approvedâ€

That's a cool setup.

Don't those ornaments on top of the TV rattle when you're watching a film though?

If you're looking at a new soundcard I'd consider the Auzentech X-Meridian:

http://www.auzentech.com/site/products/x-meridian.php

The other option would be some sort of USB DAC. That would be the best music option but there aren't that many which offer a SPDIF passthrough for films. They tend to concentrate on stereo outputs.

This forum is worth looking at when choosing a soundcard:

http://www.head-fi.org/forums/forumdisplay.php?f=59

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Yes, well the knickknacks did rattle A bit, but I taped them down with thick, double sticky back tape. Fish swim, birds fly and wives decorate.

Room buzz was a problem, the Definitive 7000SC towers have 3, 14 inch long throw LEF drivers with a 1000 watt LEF amplifier in each speaker. It's impressive. The Master and Commander cannon fire scenes or Top Gun jet blast would light up the room with rattle. The glasses in the wet bar were on glass shelves and rattled like mad. I put a felt cloth sheet under them to quiet them. Wall decorations have felt furniture leg pads taped behind where they touch the wall. Other such measures around the room have solved this problem. Perhaps this forum should have a topic for quieting wify decorations in the HT.

The wife won't dust any knickknacks taped down, I must. The felt sheets on the glass shelves are carefully cut and sized to look like they are part of the shelves (a glass border around the felt). The felt is green to match the pool table, so they don’t look like tacky additions. Home Theater and marital bliss can co-exist.

I figured that having a simple digital bit stream from the MB to the HT receiver would suffice and in fact be optimal. Perhaps I need to revisit and study this. What do the S/N ratio specs mean? Do they relate to the bit stream or are they simple traditional S/N ratios for the analog outputs on these devices. What sorts of things can corrupt the bit stream? Thanks for the link to the forum. I’ll spend some time studying this.

And thanks for the compliment on the rig.

*drool*
Six 14" drivers? .. thats a lot of cardboard moving around

Very nice looking setup there, and I beleive it sounds as nice as it looks.

Ive been wanting to do the same thing with optical out from my soundcard to HT receiver. what kindof connector are you connecting to on your receiver?

The Yamaha receiver has three choices in each channel for audio input; analog right and left channel, SPDIF coax and SPDIF optical. The receiver auto selects which one to use (you can also force it with a manual setting).

The motherboard comes with an adapter that installs in an expansion slot that puts out both SPDIF coax and optical.

I simply install an optical cable between the HTPC and the receiver.

By the way on the matter of using the optical output from the motherboard vs. a high end sound card, I’ve thought it through and concluded that it makes no difference and the motherboard connection is fine, just as good as the high end add on card.

I put my electronic engineers hat back on (I retired from engineering some years ago and went to the dark, business, side).

Here is the reason.
Noise or distortions in audio can occur in ways listed below:

1. Noise and nonlinear action when in the analog domain. This can only occur at the source (music studio) before the analog to digital converter (ADC), or after the digital to analog (DAC) converter at the listening end (home theater).

2. Clock timing dither and noise at the transition from analog to digital domain and back, the ADC and DAC. This noise causes bit errors at the digital domain creation, ADC, or analog signal errors when transitioning back to analog, DAC, to drive speakers. The clocks on both the ADC and DAC should ideally be identical and there should be no noise on the strobe that cycles these converters in order to faithfully reproduce the sound.

3. When in the digital domain the only error that can be introduced is a complete bit flip. Additional anomalies can be introduced by the software (or firmware) algorithms that decode various sound formats such as production of 7.1 surround from a 5.1 encoded DVD, or THX from a DVD with only two channel stereo. But this would be called a feature by software engineers not noise. Clocks can drift and timing noise can ride on the digital bit transitions (and do) as long as a bit is not lost.

4. The only likely source of bit flip errors in the digital domain is at the point of reading the media (CD or DVD). The computer has such a vanishingly small chance of this occurring to make such an error to be non-existent. Otherwise computers would crash or lock up all the time because software instructions would become garbled.

Thus sending SPDIF via the motherboard or via an add on sound card makes no difference. However if your computer does not have an SPDIF output by all means get a sound card with one.

In general I believe that doing the digital to analog conversion inside a quality home theater receiver is superior to doing it inside a PC. My Yamaha has no switching power supplies, analog only and the DAC is designed for high fidelity with a precise steady clock and high quality DACs. If you must decode 5.1, 7.1 inside the computer and send analog by all means get an add on high quality sound card. These cards will likely have a power supply for the DAC that is immune from the PC switching power supply noise and superior DAC clock dither that will reduce errors in the analog signal.

Also an SPDIF optical connection could be superior. Ground loops from the computer to the receiver could allow computer noise to get into the analog output of the receiver. This problem could be averted easily by how the electronic drivers and receivers for the electric SPDIF audio coax line are designed but why take chances with it, this can only be controlled by the design engineer, you can’t control this.

Those of you who disagree please feel free to weigh in.

I was thinking that all those speakers could be causing some rattling.

Apparently you can have problems with light fittings too: High volume makes the bulbs vibrate in the light sockets.

Digital sound quality is a contentious issue. You're just as likely to find people saying there's no difference as there are people saying that there is.

There's quite an interesting article about digital audio issues here:

http://www.positive-feedback.com/Issue22/nugent.htm

(The author sells expensive soundcards so has an interest in promoting computer audio over CD players. Despite that it's still a worthwhile read.)

Light bulbs, light bulbs, Oh My Gosh. Now I'm going to be running around the room, obsessing over light bulb rattle. I know, I know, I’ll remove all of the light bulbs from their sockets before playing any music. I’ll need to get a flash light to keep from stubbing my toes though. Do the bulbs and batteries rattle in flash lights? Seriously I’ll check it out; one truly must obsess about these things.

Good article, the only part I don’t understand though is how the S/PDIF "coax" cable contributes to audible noise due to jitter, especially that the optical cable is worse. In any system where audio byte to analog timing is set by the DAC, clock jitter in the computer data transmission is not a problem. I my Yamaha the audio digital data is “handledâ€

Absolutely.

Have a look at this booklet about room acoustics too:

Room Acoustics Booklet

It's not really an issue at low volumes but the louder you have the speakers the more likely it is you'll run into these issues.

Here's quite an interesting article about using a PC as a digital music source:

http://www.audioholics.com/tweaks/do-it ... ource.html

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Amazing stuff, thanks for the info. The article on building a high fi PC cleared up the S/PDIF timing jitter business. In fact he agrees that timing jitter only maters at the point of conversion. I haven’t read the article in detail yet but will. Apparently the S/PDIF output bit timing jitter of CD ROM players is pretty bad and some PC’s based audio systems do not clean it up. He’s using an external DAC.

As to the second article on acoustics, yikes and gee whiz I haven’t even started to clean up room sounds. Now I’m going to have to get a signal generator. Actually I’ll get the “Hi-Fi News & Record Review Test Disc IIâ€

There's a surprising amount you can do to make noticeable improvements that don't cost money.

Rebuilding the house for a better layout isn't one of them though.

For the soundcard I'd suggest possibly auditioning a few like you would with any other audio component.

It's one of those things that's worth testing to see whether you feel there's any improvement with your system.

It could be a bit tricky to actually do of course.

Edit: Have a look at this article about optical digital cables too:

http://www.audioholics.com/education/ca ... ory-basics

(The article is reprinted from a site that sells audio cables.)

Also another room acoustics article (with references at bottom of page):

http://www.audioholics.com/education/ac ... erspective

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I found these test tracks in mp3 format.

http://www.realtraps.com/test-cd.htm

They go from 10 Hz to 300 Hz in one Hz increments. They are intended to help get rid of standing waves in rooms with LFE speakers, but they should be great for finding room resonance rattles & other noise. I'm still looking for a good test tone CD for frequencies above 300Hz. The “Hi-Fi News & Record Review Test Disc IIâ€

There are quite a few test CD options that go up to 400hz+:

http://www.google.co.uk/search?hl=en&rl ... t+cd&meta=

Which is best depends where you're ordering it from really.

You can even get a test CD with your own custom choice of tones on for $50USD.

http://www.marchandelec.com/sweeps.html

That's quite a lot for someone to burn a CD-R.