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Dirac Live Room Correction Suite

198.144.198.194
Posted on March 27, 2012 at 17:30:43
Wesley Miaw
Manufacturer

Posts: 45
Location: San Jose, California, USA
Joined: February 14, 2012
 I just tried out the Dirac Live Room Correction Suite software on my MacBook and I'm very impressed. I think this is something everyone should try out because it will help make sure your setup is performing at its best.

Using a microphone the software takes measurements and then lets you create audio filters to adjust the frequency response and impulse response. I used a Behringer ECM8000 microphone with calibration file and tried things out with both Airfoil and a USB -> S/PDIF converter to bypass the MacBook's sound card and feed directly into my Neko Audio D100 Mk2 DAC.

I am running this in my 2-channel setup at home, but it also supports surround sound and larger venues like an auditorium. The audio filter adds a noticeable delay to the sound, so if you use a HTPC you will need to delay your video to match. The software has a simple on/off switch that makes it easy to evaluate the audio filter's effect.

With Dirac Live engaged, the music was more centered and the sound stage moved closer so its distance equaled my speaker distance. The frequency response was more balanced and there was less distortion. I'm so pleased with the result I intend to continue using this in my setup: MacBook (w/Dirac Live) -> Airfoil -> DAC.

I've attached my measurements and the predicted post-filter results for the left channel.




The original frequency response measurements for the nine measured positions.




The post-filter predicted frequency responses at the nine measurement positions.




The original measured average and predicted average frequency response.




The original impulse response measurements for the nine measured positions.




The post-filter predicted impulse responses at the nine measurement positions.




The original measured average and predicted average impulse response.

 

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RE: Dirac Live Room Correction Suite, posted on March 27, 2012 at 23:41:12
play-mate
Audiophile

Posts: 948
Joined: November 21, 2008
 Hey Wesley,

I´m very happy on your behalf so congratulations to your FIR filter implementation.
Finally also avaliable on the Mac-platform.

I had a brief look at Dirac a few month ago, and was disapointed that so little technical information is released by the manufacturer.
Maybe they will reveal some more details by time.....

There is no doubt that this kind of digital correction has an incredible future as the results can be astounding.
I´ve run Acourate on Windows for almost two years, and I´ll never look back.

Thumbs Up !

kind regards



Hysolid // Mytek Brooklyn // Spectron Musician III // Analysis Audio Omega

 

RE: Dirac Live Room Correction Suite, posted on March 28, 2012 at 07:19:57
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Only supports up to 24/96.

 

RE: Dirac Live Room Correction Suite, posted on March 28, 2012 at 08:42:45
Wesley Miaw
Manufacturer

Posts: 45
Location: San Jose, California, USA
Joined: February 14, 2012
 Thanks. :) I think I took a look at Acourate earlier but it wasn't compatible with my primary software chain (Mac OS X and iTunes). Glad to hear it works well for you!

 

RE: Dirac Live Room Correction Suite, posted on March 28, 2012 at 21:39:05
ThomasPf
Audiophile

Posts: 835
Joined: January 22, 2002
 While predicted behavior is interesting information, is there actually a way to measure the room response with the filter active and compare befor and after.

I always check my work in Acourate with this simple check and it helped me detect multiple times when I fumbled up my measurements.

A completely flat reponse is not a very natural room response b.t.w.

Cheers

Thomas

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 05:43:41
aljordan
Audiophile

Posts: 1252
Location: Southern Maine
Joined: November 4, 2003
 Hi,

While the predicted frequency response at the listening position looks impressive on the graphs, if that is indeed the response at the listening position the resulting sound is probably quite thin. Can you choose a target response curve? If so, you might try going for a down-sloping response starting from 200 Hz to around -6dB at 20kHz, and maybe throw in a little BBC dip around 2kHz.

If you like the results of Dirac but it doesn't offer target response curve functionality, you may consider looking into Acourate or Audiolense. You would have to use a Windows setup to create the filters, but you could play back on a Mac via Pure Music and LAConvolver.

I would be surprised if an actual room measurement looked as good as the prediction.

Thanks for bringing Dirac to our attention. I wasn't aware of it.

Alan

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 05:54:41
aljordan
Audiophile

Posts: 1252
Location: Southern Maine
Joined: November 4, 2003
 I am going to set myself up for a beating and suggest that a well optimized room correction filter for an already decent room will offer improvements far beyond that heard by a greater than 96 kHz sample rate.

Alan

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 08:41:36
Wesley Miaw
Manufacturer

Posts: 45
Location: San Jose, California, USA
Joined: February 14, 2012
 I could probably re-run the Dirac Live measurement software while the Dirac Live audio filter was active. But another option would be to run something like Room EQ Wizard while the filter was active to get more detail.

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 08:54:16
Wesley Miaw
Manufacturer

Posts: 45
Location: San Jose, California, USA
Joined: February 14, 2012
 I can understand why a flat response would be "thin" sounding, but that is actually what I prefer. You can choose a target response curve (and add points to the target curve so it goes up and down multiple times). The default target response curve the software proposes does indeed slope down, although I don't think it's -6dB down at 20kHz.

My hardware chain doesn't introduce fatiguing distortion, which is one reason people sometimes look for something that reduces the high frequencies. I think the original measurements might be close to the slope you describe, which is a "warmer" and "richer" sound, but less desirable to me personally.

I agree with you that the actual measurements with the filter on are likely to look close, but not exactly the same, as the nine predicted frequency responses (not the average predicted response, which is why I included the nine predicted measurements graphs). I'm sure that because I'm not making sure everything is exactly-exactly the same and that this is in-room there will be variations between measurements.

Thanks for pointing out the filters created under Windows could be used in Pure Music or LAConvolver. I'm familiar with Pure Music, but this is the first I'd heard of LAConvolver.

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 11:30:44
Tony Lauck
Audiophile

Posts: 13629
Location: Vermont
Joined: November 12, 2007
 High frequency balance for a natural sound depends on the three dimensional response at your listening position, which is a function of both speaker directivity and room acoustics. There are many different ways of defining what constitutes "flat". In addition, the response that one hears depends on the response captured or engineered into the recording, so a system that sounds OK on one recording might be dull on a second or bright on a third. The frequency balance captured by a microphone depends on its position including distance from the musical instruments and the musical instruments radiate different amounts of high frequencies and hence brightness according to the angle from them to the microphones. In addition, ambient sound in the hall is colored in various ways. Even the amount of humidity in the air affects the sound.

With all of these factors in play, it is an art, not a science, to tune a playback system to capture an appropriate high frequency balance. One has to select a set of reference recordings and make adjustments until these represent a suitable compromise between "too bright" and "too dull". If one does this than the large majority of recordings can sound musical without further adjustments (except possibly playback volume). It is generally conceded that "flat" is not the best setting if one want to playback most recordings, as most recordings are closely miked and many microphones come with high frequency boost. Typically, a drop of about 4 dB from 1 kHz to 10 kHz produces a reasonable compromise. With my studio monitors I achieve this balance by adjusting the speaker controls, adjusting the position and aiming of the speakers and placing damping material at various places on the walls.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: Dirac Live Room Correction Suite, posted on March 29, 2012 at 20:24:02
ThomasPf
Audiophile

Posts: 835
Joined: January 22, 2002
 How, do you know how well the correction is working without doing this step?

 

RE: Dirac Live Room Correction Suite, posted on March 30, 2012 at 09:02:48
Wesley Miaw
Manufacturer

Posts: 45
Location: San Jose, California, USA
Joined: February 14, 2012
 Well, I could hear a difference matching the proposed filter changes, but you're right it would be best to re-run measurements to verify. I didn't have much time that evening so I skipped that step. I am also assuming that the software's filters are implemented and executed correctly.

 

RE: Dirac Live Room Correction Suite, posted on January 6, 2013 at 08:21:19
Endurance_Man
Audiophile

Posts: 2
Location: Brazil
Joined: May 12, 2012
 Play-mate,

Were you able to run the Dirac Live filter and compare with the one of Acourate?

Are they (or any of the two) very transparent or some detail is lost?

I would be very interested in better understanding which one is better from a sonic perspective.

Thanks!

 

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