User:Nicolaprada
From DRC
MY ACTUAL SYSTEM
Right now my system is:
SONY DVD TRANSPORT -> Apogee Wide Eye SPDIF 1m -> FANLESS HTPC-> Apogee Wide Eye SPDIF 1m -> BRYSTON BDA-1 DAC -> Bryston XLR Cables 1m -> BRYSTON BP 26 PREAMPLIFIER -> Bryston XLR Cables 1m -> BRYSTON 3B SST-C AMPLIFIER -> XLO ULTRA 12 -> ProAC D15 speakers.
I use it both for stereo music listening with all phase 44.1Khz filters with 65536 coefficients and a delay of 8192 samples and for video (DVD) with minphase only 48khz filters with 32768 coefficients with a delay of 1024 samples that let me avoid lipsync problems.
For measurement taking I use a separate notebook with a m-audio firewire audiophile soundcard (http://www.m-audio.com/products/en_us/FirewireAudiophile-main.html) and the calibrated mic kit sold by the german ibf akustik (www.ibf-akustik.de). To record the sweeps I am using Acourate Log Sweep Recorder 2, a free software written by Ulrich Brüggemann (http://www.acourate.com/)
I am generating the filters with DRC 3.1 (http://drc-fir.sourceforge.net/)
THE FANLESS HTPC IN DETAIL
The fanless htpc has been very simple to build. After a couple of weeks looking for the right hardware I selected a nice to see htpc fanless case, the Silverstone LC19S:
(http://www.silverstonetek.com/products/p_contents.php?pno=lc19&area=usa)
The VIA EPIA EN1200 fanless motherboard:
(http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=399)
I added 512mb of DDR2 Ram, an internal power extension wire, a PCI Extension card and the RME HDSP 9652 soundcard:
(http://www.rme-audio.com/english/hdsp/hdsp9652.htm)
I am not using the soundcard daughter board wich provides a 3rd ADAT in/out and a Wordclock I/O.
I built the fanless htpc in about 15 minutes.
For the htpc software I believe the best option is to use Linux and Brutefir (www.ludd.luth.se/~torger/brutefir.html).
Here I had the first big problem: I am a Windows guy, I do not know anything about Linux. Luckily I found the solution implemented by Ulrich Brüggemann (Uli) that anyone can download for free here: www.acourate.com
Based on SBP Linux, it let you start the htpc from an usb stick, an hard drive is not needed. Uli provides ALSA config and the driver for the RME HDSP too and sample files that let you immediately listen to your music with SPDIF in/out. You just have to put the usb stick in the usb port of the htpc and push the turn on button. Thanks Uli for this.
Reached this point I only needed to learn how to create the filters and it is mandatory to read several times the documentation provided with DRC and the other tools. Despite I did it, I made a lot of mistakes that drove me to dead points but I kept on trying until I was able to create the first, good, filters.
THE RESULTS
The improvement on the sound is amazing. No more boomy bass, bigger and focused image, more resolution. I would never be able to listen to my system without the benefit of digital room correction. It’s not an easy path but if you have room problems like I have you must try it. And you will never go back.
After I got the CD sound corrected the next step was to create minphase only filters (to avoid delay) at 48khz to watch DVD and despite the correction is less powerful than the one used when listening to audio CD only, the results I am experiencing satisfy me. I modified Uli's scripts to check for the input port and the samplerate of the RME card and now If I put an audio cd inside the transport it is correctly recognized and Brutefir starts with the 44.1khz all phase filter. If I switch to a DVD, Brutefir is automatically restarted with a 48khz minphase only filter. I the DVD player is turned off the htpc will get the audio input from the Toslink. That means I can have my satTv or my XBox 360 corrected too (minphase - realtime). A note: I initially thought I could have had connected both at the same time but it seems that the RME HDSP can receive SPDIF Toslink signals only on the ADAT1 in, so I am keeping connected the Xbox :)
I am really satisfied with the results I reached. Without the help provided by Denis, Uli and people like Ed with this site, I would have never been able to reach this point, so I hope my contribute will simplify the path for people that are ready to start this adventure.
Nicola Prada
