HTPC with cross-over

[Ninfendo]

Hello Fellow Audio Fanatics!

Following the completion of my enourmous Petit Filou Speakers, I still have not solved the problem with their active filters:
The Ariel as never seen before (incorporating Stig Erik Tangens Almighty subwoofers)

As most of you DIYers out there probably know a conceptual idea tend to grow out of control pretty quickly, I am therefore writing hoping that someone will give me an reality check.

After finishing the Petit Filou project I was initially planning to build a normal Active Crossover using OP-amps, however many people recommended me the DCX2496. The problem with the 2496 is that it is a rather untidy solution if you like me have a preamp with multiple sources. I therefore shelved the whole idea.
I think that keeping the signal digital all the way would be preferable as this should result in the highest possible sound quality.

After asking around at this website ( Pure Digital amplifier modules? ) I was recommended http://www.d2audio.com who produces Class-D amplifier which integrades programmable x-overs. However, due to D2's priorities these modules cannot be obtained by us DIYers. This brought me back to square one.

I still wanted an all digital signal path (or at least digital to the highest extent possible). I then began looking into the options of using PC software for doing the actual filtering, first stop was:
http://kxproject.lugosoft.com/index.php?skip=1

After reading some articles on this website I quickly realised that the kxproject was a No Go due to the sound quality from an Audigy2. I must admit though that I am very curious to know what the performance of the new Creative X-Fi is like:
http://www.creative.com/products/wel...bcategory=208&

Next stop was ShinOBIWANs article on PC XOs:
A how to for a PC XO.
This is when it started to get really interesting, however, with a GBP 5000 price tag this is one expensive solution.

Following the thread I found a possible solution that would allow cross-over, digital room correction (DRC) and phase correction
http://www.duffroomcorrection.com/wiki/User:Birkinshawc

All this runs on an application called BruteFIR developed by Anders Torger: http://www.ludd.luth.se/~torger/brutefir.html
It appears that BruteFIR would allow both digital output as well as an analog filtered signal using a multichannel Sound Card.
This seems like the best solution available at present.
Given that BruteFIR has been used with 1GHz Athlon processors a new top of the range PC could probably do all its filtering duries as well as working as a media server.
Note, BruteFIR runs on LINUX a guide for setting up a Media Center PC on LINIX can be found here: http://www.extremetech.com/article2/...1814896,00.asp
Although a lot of focus is on the Video aspects in this article, it's the Music capabilities which I think is of interest and hence the Video can be ignored. With a 500Gb harddrive plenty of uncompressed music would fit inside. A DAB PCI card could also be added.

OK, so far so good. There is however one question that remain...
The amplifier!

The ideal solution would be to find a digital amplifier module which can filter out appropriate channels from a 6 channel SPDIF input. Any suggestions???
The alternative is using Class-D chip amps such as:
ZAPpulse 2.3SE http://www.lcaudio.com/index.php?page=70
UCD180 http://www.hypex.nl/
AMP6 http://www.41hz.com/

An amplifier module such as the AMP6 is small enough to be integrated into the CPU case. A really cool solution would be to use the Uneed x15 with 3 AMP6 modules built in:
http://www.iuneed.com/x15e.html
Amplifier modules and CPU could all be using Water cooling making everything very silent.

OK, that was some thoughts, am I completely nuts? Are there any better ways of doing this?

[ewildgoose]

The fully digital amps are neat in that you can do volume control with them, but they are over-rated in quality terms (to some extent). There is some evidence that the "best" digital amp that can be built right now would be an analogue amp with traditional DAC and volume control. However, agreed that the part count and complexity is a lot lower with a fully digital class-D

Please see the room correction wiki and write up your experiences at:
http://www.duffroomcorrection.com

You can find my page on their - I use lots of UCD and Zappulse amps for amplification. A multiway motorised stepped attenuator to control volume and a beefy PC to supply all the audio and video and FIR filtering required (I use the DACs on the audio cards and they seem pretty decent to be honest)

Good luck

Ed