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Project Mediastation is Officially Underway

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My long-time project of creating a computer based high-end surround pre-amp/processor and audio- and video source has now officially started. It’ll be a mix of newly purchased components and pieces from my current HTPC for the electronic bits and then a custom designed and manufactured chassis made from aluminium and brass.

The Mediastation is built to provide the highest possible audio and video quality while using as little energy as possible. I’m using an AMD Be-2350 CPU, an Auzentech soundcard (the X-Fi 7.1 Forte) feeding an amplifier with an analog signal, an Asus HD4350 Silent HDMI graphics card for hardware 1080p decoding and processing, a 5.25″ Blu-Ray drive and a couple of hard drives together with an mATX motherboard and an ATX power supply. These components need to be housed in a good looking, solid small case that is noiseless from a normal viewing and listening distance (2m). The end result is a system that can rival the very best stand-alone high-end audio pre-amps, processors and audio- and video sources using less power than many digital-broadcast set-top boxes.

When using hardware acceleration on the current generation of graphics cards there’s no need for a powerful CPU, even an Atom can just about manage to play Blu-Ray titles using decent graphic circuitry. Both AMD and NVIDIA score about even (and very good) in Silicon Optix HD HQV tests but the ATI Avivo UVD2 seems to display more detail at the cost of a slightly cooler-colored image. My choice of the Asus HD 4350 card comes from the fact that it’s passive, inexpensive, draws less power than the NVIDIA competitors and has a HDMI output. I’m certain that the image quality is spectacular and the CPU off-loading is equal with either manufacturer.

Auzentech X-Fi Forte 7.1

The Auzentech X-fi Forte 7.1. True high end audio for computer based audio processors.

The Auzentech sound card uses the same components and rivals the specifications of some extremely expensive audio and home-theatre gear, it uses an 24bit/192kHz AKM AK4396VF DAC through a National LM4562NA OPAMP to drive the front channels (where the OPAMP is replaceable) to achieve an A-weighted SNR of -116dB, THD+N of 0.0016% and Dynamic Range of 116dB at using a 24bit/48kHz source. The Lexicon MC12 has a SNR of -108dB and THD+N of 0.008% and the Arcam FMJ AV9 Pre-Amp Processor has a SNR of >98dB and THD+N of 0.0015%, for comparison. These specifications is far away from defining high-end audio, but they serve as a suitable reference. The X-Fi forte also has a separate heaphone amplifier on-board and analog power circuitry to clean up the power from the main power supply.

The first tests shows breathtaking detail, clarity and contrast when viewing the Matrix and 300 on HD-DVD on my 46″ Sony 1080p TV over HDMI. I bought these discs last year before the HD-format war had ended and I thought that they would be useless now, but the very affordable (1250kr) LG Blu-Ray drive I picked up also had HD-DVD capability, an added bonus that I missed in its specifications… It also came with PowerDVD Ultra to be used for hardware acceleration of ripped movies as well as playback of DVD’s and HD-discs. First tests shows that some 1080p x264 rips in a Matroska container works and some don’t, obviously they have to be renamed to .avi for PowerDVD to accept them but then about 50% of my files work and 50% don’t (they don’t show any video, only sound). I’ll look in to this more and publish my software configuration once it works to satisfaction.

The audio is equally clear and detailed through the Sony reciever (analog inputs pass-through, working as a passive amplifier) and Mirage Nanosats. Since the system currently lacks a subwoofer only light music can be scrutinized, but voices and dialog are hyper-real and compression artifacts in MP3-music becomes obvious once I listen for them. This raises the qustion if audio and video can become too real, that too much defects are revealed. I don’t think so, the grain and noise from the film stock is also clearly visible in the high-def movies I tried and they just remind me that while nothing is perfect in this world, we can only try to get better and push ourselves and our technology forward.

References

Auzentech X-Fi 7.1 Forte
Driverheaven HD Nvidia vs. ATI Video Quality Comparison

Posted in Projects March 30th, 2009 by
Anders
and last updated January 4th, 2010. Tagged with .


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