Digital Room Correction - Friend or Foe?
Room interaction plays a huge part in how sound is perceived at the listening position. Even the best speakers are hampered by in-room resonance and reflections that bloat or obscure the sound at certain frequencies. In an ideal world, our rooms would be capable of a reasonably flat line audio response between 20Hz-15KHz (the audible range for most of us); the reality however is often far from this proposed optimum. Digital correction software works by playing a full-range frequency sweep, recording the response with a measurement microphone, and then inverting the measured response, thus smoothing room response artifacts.
Initial experiments were performed on the free open source DRC program called ACXO that unfortunately does not appear to support Vista 64 properly. The measuring aspect works fine on the Vista 64-bit OS; however, attempting to apply correction causes the program to hang without ever making a change. If you're using Vista 32 or XP 32-bit, we'd recommend you check it out.
As attempts to use ACXO with Vista 64 failed, I decided to go with the full version of Audiolense 3.0 for two-channel setups. The cost for the basic single user license is around $190, which is not exactly cheap for most of us, but we must recognize the level of work that goes into creating and supporting such products. There are a few alternatives to Audiolense varying in complexity, ease of use, and of course cost. For example, Acourate is a standalone package which seems to have more complexity to its GUIs than Audiolense, although there are video tutorials available on the Acourate website to help users get started.
The beauty of both Audiolense and Acourate is that both companies are new budding enterprises, which leads to support being handled directly by the authors of the software. We hope this continues as emails are currently handled within hours of being sent. Another software option is Art Teknika's Console that can be used with the Voxengo Curve Eq plug-in and used for DRC. The expansion possibilities with Console are huge, with plug-ins supporting digital crossovers and rerouting of input and output signals as long as the hardware used is capable.
Note that all of the software mentioned here features 30 day trial versions with limited functionality to give you a taste of what DRC is all about, so if you're interested but don't want to plunk down hundreds of dollars on something you might not like that's a nice option. You'll also need a measurement microphone and preamplifier. We're using the affordable Behringer ECM8000 and UB802 (now discontinued) to take room response measurements. In all, expect to fork out an additional $150 for these two components. The microphone preamp needs to support "Phantom 48V power" if you're using the ECM8000, so make sure you buy one that's compatible with this requirement.
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kleshodnic - Monday, December 1, 2008 - link
Uh, just go digital out (TOS/link or HDMI) to a receiver and let ther receiver do the DAC'ing.Want a better DAC? Buy a better receiver. Not only will you get the better DAC, you will get a ton of other great features with a higher end receiver.
All this talk about computer audio is assuming that you would want to come analog out from the computer. WHY?
phusg - Tuesday, December 2, 2008 - link
It would be a lot easier I agree, but AFAIK only really expensive top-end receivers can challenge the analog out you can get from a quality consumer audio card with upgraded opamps, especially when it comes to stereo music. They are also not usually moddable. Can you link to a review of receiver with audiophile quality stereo DAC?pedobosz - Monday, December 1, 2008 - link
an interesting place to publish such an article. Have you thought of perhaps submitting to Stereophile or The Absolute Sound ? I'm sure you are just trying to raise the awareness of the PC crowd to the possibilities of great audio, but reading through the other replys, I think you are preaching to the deaf......with the exception of the Martin Logan fellow.jnmfox - Monday, December 1, 2008 - link
Computers and audio (mostly Home Theater) are my main two hobbies. I agree this article doesn't fit here at anandtech.com. I've never understood the esoteric audio crowd. If you want quality audio information go to audioholics.com or other reputable audio sites.jabber - Monday, December 1, 2008 - link
I have to say the article and lengths gone to are way over the top for what in most cases is required.The kits combined with the PC audio side is way esoteric too.
Well intentioned but sledgehammer to crack nut.......
haukionkannel - Monday, December 1, 2008 - link
Hmmm... When we talk about HiFi nothing is "bit over".For a hifi system this was relative middle range solution. The biggest consern, if you have to find one, is that the speakers will most propably have the biggest effect an the hearing experience. These type of speakers ar not meat to be the most precise in their "room" picture. And I don't say that it's a bad thing! They are good speakers. Some studio monitors would maybe be better for testing the PC as an "Hifi" sound source, because they try not to affect the sound at same way as some High end HiFi speakers, but again it's more of a matter of taste. For example Genelec speakers sound good for Vocal based music. These in here are better in music where accuracy is not so important. So it allso depends on what music you like to listen to. Just like someone above said.
I would like to see how the sound compares between good Hifi cd-player and a PC. With the same music piece and speakers. This set with those tubes can make the sound varmer, that is good for some not so good mp3 files. More accurate monitor speakers and normal amplifier, will most propably reveal the difference between good cd and not so good PC based mp3 more clearly.
Most people who are really interested in HiFi systems spent even more money than in test to their system. The real guestion is that is the PC good enough soundsource for system like that.
jabber - Monday, December 1, 2008 - link
Yes but real high end hifi is really usually bought by what Top Gear would call 'cocks'. Folks that just see money and how much they spent rather then just enjoying music. $50000 hifi systems geared to playing just 10 specialist audiophile CDs just screams "I've led a sad and lonely life!" to me.Show me a $1000 system surrounded by piles of CDs and LPs, now thats an exciting system!
The readership of this site I would say on the whole would have far more modest hifi setups.
Once you spend so much on a hi-fi you fall into the trap of listening to the equipment rather then the music itself.
Spivonious - Monday, December 1, 2008 - link
Spending that much time and effort to listen to pop music is just about the silliest thing I've ever heard.At least put something on that will work the equipment, like a Beethoven string quartet, or a Bach choral work.
And you never even touched on the issue of vinyl vs digital. To my ears, vinyl sounds so much more organic than the plasticy sound of CDs, even through a $15,000 tube-driven stereo system.
Rajinder Gill - Monday, December 1, 2008 - link
Actually, I'm just listening to some Vaughan Williams right now. Just because there's no mention in the article does not mean to say I live without classical pieces.Peace...
Hyperion1400 - Monday, December 1, 2008 - link
Amen to that. There is no set style of music for audiophiles. I personally enjoy metal and classic punk (bad religion,sex pistols etc.) as well as a mix of classical composers(I have always had a strange love for Beethoven's 9th after watching Neon Genesis Evangelion)Also, will you be doing a review of the X-fi Elite Pro or will you be primarily dealing with external hardware. I know I will most likely be shunned for mentioning such a thing in the same post as (vicariously) declaring myself an audiophile, but I absolutely love mine. Without that card and my Senhiesser HD 650s, I don't think I could listen to my music/games the same way again(no pun intended)