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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Christobevii3 - Monday, December 1, 2008 - link
What about using a dts/ddl sound card to output to a basic receiver?Rajinder Gill - Monday, December 1, 2008 - link
If going to the nth degree for 2 channel it’s hard to look past USB-I2S in async. For multichannel, a DTS/DDL card is perfectly adequate. Although I’d still use an external solution if I could find one.wolrah - Monday, December 1, 2008 - link
How do you figure I2S is any better than S/PDIF? S/PDIF supports up to 20 bit resolution at either 48 or 44.1 KHz, so it can carry a CD audio stream natively. The bits on the disc are the bits flowing out the optical port on the back of your gear of choice.In theory an I2S signal will be able to take more interference, but when we're talking optical signals in a home environment the kind of interference needed to make a difference would be on the scale that you'd never be able to listen to anything.
Goty - Monday, December 1, 2008 - link
Well that's easy to answer:Nope. I'll stick with my Martin Logans, tyvm.
wolrah - Monday, December 1, 2008 - link
In fact it easily can, because plain and simple reading from the disc itself is error prone. A one time rip to WAV or [lossless format of your choice] using cdparanoia on its insane mode output through a high quality sound card will be the same as or better than any silly 4 digit CD player.Even playing straight off the disc, there's no reason to believe any "audiophile" gear will play a CD any better than any other CD player unless there's a design flaw like a crappy power supply.
On the note of power supply, am I the only one who laughed at the bit about the battery vs. the wall wart? Who wants to bet that he's never double-blind tested that one. That's the wonderful thing with A/V gear snake oil, it's very easy to hear what you want to hear.
mindless1 - Monday, December 1, 2008 - link
I've hand-built amps for years and double-blind tested batteries and wall warts. Yes there is a difference. A good (read: overkill for anyone not into building audiophile equipment) localized power filter stage, if not localized regulation, would ideally negate the difference between the two power sources but that can also unnecessarily increase the build complexity, time, and cost.PS the battery is almost always inferior assuming the wart has proper shielding or is inadequate in capacity, and generally I refer to a wart as only a transformer and rectification stage, not trying to build an entire high precision linear regulation stage inside of it due to limited space and EMI.
Rajinder Gill - Monday, December 1, 2008 - link
Martin Logan makes electrostatic loudspeakers if I recall.I'm not sure where that fits into using a PC as a transport and for DRC. Unless you're refering to the approval of open baffle design loudspeakers using te supravox drivers?plonk420 - Monday, December 1, 2008 - link
this is surreal...my $20 Chaintech AV-710 just died in the last 48 hours. i've been trying to resist the Head-Fi audiophile talk and try to find cooler heads to verify whether or not i should go X-Fi or DAC (something silly looking like the HotAudio HotUSB1 or Silverstone), or try to figure out if i'm experiencing the placebo effect "falling back upon" my ALC883, which i can swear "doesn't sound as good" EVEN THOUGH i'm fully aware of the power of placebo.
i'm not sure i liked the mixed bag of positive and negative reports on (cheap) X-Fi vs Xonar vs X-Fi USB vs some DAC vs E-Mu 0404/0202
mindless1 - Monday, December 1, 2008 - link
Choose a Creative card for gaming sound effects. Choose a DIY DAC for highest audio quality at a reasonable price. Buying some cheap commodity grade DAC is a gamble, I'm not familiar with those two products you mentioned but generally in the consumer segment and price range you end up buying an idea, a type of tech but not excellence in that execution.MOtherboard integrated audio usually doesn't sound as good including one using ALC883, though someone with poor hearing or gear may notice the difference less and less depending on where the weakest link in the chain is and how bad it is.
Gannon - Monday, December 1, 2008 - link
I have an X-Fi and it's better then my audigy, mind you I got the more expensive version with front panel and the remote. I use it for everything and have never had a problem, though I don't use vista at all just XP.