User:Nicolaprada
From DRC
THE NEED OF ROOM CORRECTION
I always loved music but it’s just a couple years I got really interested in the hi-fi world. My first “good” system has been the combo NAD C352+NAD C542+B&W CDM1NT. Not the best system in the world but the one who opened my eyes and my ears: music was not what I listened to until then whit Kenwood or Aiwa subsystems.
As many of new audiophiles I immediately got caught by the upgrade syndrome. I started playing with cables, then I replaced the B&W CDM1NT with the ProAC D15. Wow, this was the bass I was looking for but I was missing amp power, I knew that the D15 were able to give much more because I had auditioned them before with two giants mono amp.
So I bought my first serious amplifier, a Bryston B100SST. I loved (and still I do) this little monster. Built like a tank, with 20 years of transferable warranty, powerful, neutral sounding. This was the ampli for me.
After a couple of months I moved into a new house, with a bigger lounge but the systems had to be placed asymmetrically and room treatment was not an option ‘cause of my wife. I realized I needed digital room correction, a fast way to solve part of my audio problems.
But digital room corrections requires watts, good watts. I was so satisfied by the little Bryston I upgraded it to the combo Bryston BP26 and 3BSST-C. More watts, better sound, XLR in and out, separate power supply. I love it.
Then I bought a Lavry Engineering DA10 DAC, a quantum leap from the NAD C542 internal DAC. I did not want to trash money anymore so I looked for my DAC in the pro world. In the 1000€ circle my options were Lavry, Apogee and Benchmark. I found Lavry to be the best for me.
I liked the system but the image was not so perfect because of my room and I had a lot of bass boom effect and loss of resolution because one of the D15 has to be placed in a corner.
These days I was hoping TACT (or Lyngdorf) was ready to sell some reasonably priced new correction system to be put between transport and dac, I didn’t want to sell my new and loved Bryston BP26 preamplifier for the TACT 2.2 / XP pre.
I just needed a tool working in the digital domain only able to correct the system response, like a DEQ2496 but more advanced because I needed a correction in the time domain too.
Browsing the internet I found DRC and Acourate, softwares that can stop the typical upgrade path and open the eyes and the ears of many audiophiles who think the problems rely in the components. When you have above average components, the problem is only one: the room. And it is a bigger problem than what you can think about before you correct at least a part of it. I always thought the room was responsible of the 5% of the sound of the system. I found it is responsible of more than 40-50% of it. Before changing components, a good things is to work on the room with passive (if you can) or active treatment.
Not requiring a graphical user interface (I have a programming background) and not having to deal with digital crossovers or multiamp active systems, I found DRC by Denis Sbragion to be more than enough to satisfy my needs and it has the advantage to be free and with source code provided. If in the future I will have to deal with crossovers I will buy Acourate.
MY ACTUAL SYSTEM
Right now my system is:
PHILIPS DVD TRANSPORT -> Apogee Wide Eye SPDIF 1m -> FANLESS HTPC-> Apogee Wide Eye SPDIF 1m -> LAVRY DAC DA10 -> 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 marked lipsync problems.
For measurement taking I use a separate notebook with an 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).
As softwares I use GLSweep to generate the impulse and the free audio editor Audacity (http://audacity.sourceforge.net/) to record it. I also use SOX (http://sox.sourceforge.net/) and Shibatch SSRC to convert audio files and to change frequency (http://shibatch.sourceforge.net/), all are free programs.
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)
Actually right now I am not using the soundcard daughter board wich provides a 3rd ADAT in/out and a Wordclock I/O. The only reason I am not using it is that the htpc case has just one PCI cutout and I didn’t want to drill it up to now cause I do not really need it now.
I built the fanless htpc in about 20 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 let you start the htpc from an usb stick so the hd 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 bass boom effect, bigger and focused image, more resolution. I would never be able to listen to my system without the benefit of digital room correction. The wow factor I had has been the same I had previously switching from Nad C352 to the Bryston B100 SST. It’s like listening to music in your car when you come back from the office and then put your CD in your 10.000€ system in the lounge.
It’s not an easy path but if you have room problems like I have you must try it. And you will never be able to 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.
With Uli scripts, 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.
The next step will be to modify Uli scripts (hopefully with the help of some Linux expert) to implement the Toslink input too in order to have also my Xbox 360 (or SAT TV) corrected (48khz, minphase). I initially thought I could have had corrected both but it seems that the RME HDSP can receive SPDIF Toslink signals only on the ADAT1 in.
I am really satisfied by the results I reached up to now, but 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
