Impulse response before and after DRC (1 Viewer)

[Jones_Rush]

Before DRC:
http://www.avsforum.com/avs-vb/attac...chmentid=12674

After DRC:
http://www.avsforum.com/avs-vb/attac...chmentid=12675

The images got clipped at the sides, but according to ETF, the distance between each horizontal line in the image, represents 20%, where "0" (of the "level" axis, not the "time" axis, which you CAN see at the image) is set to be the horizontal line in the middle.

 

[Frank Carter]

What's DRC?

 

[Jones_Rush]

Frank,
DRC is a Room Correction Device software for the PC, developed by Denis Sbragion, to be used freely. You first measure the acoustics at your listening spot, and create the "before" impulse response wave file, which contains both frequency and phase information about the acoustics at the listening spot. Then DRC work with this file, to create inverse filters which will try to "correct" the acoustic anomalies in your room (ie. frequency and phase correction).

Then you load these inverse filters into your an audio player (like winamp, or whatever) and any sound which will be played through the player, will be convolved with the inverse filter, to compensate for the acoustic anomalies in your listening spot. Only work really well for one listening spot.

At the images above, you can see the time domain corrections the DRC was able to do in my room. You can clearly see that the decay of sound is much less smooth at the "before" image. The time correction feature is what really sets apart DRC from all other regular EQs we are used to work with (Ala BFD and such).

For more information about DRC, you may want to check out here (the thread starts off topic, but soon afterwards, it becomes interesting.

In order for you to see that DRC not only work at the time domain, but also at the frequency domain, here are some before and after images of the bass response in my listening spot:

Before DRC:

http://www.avsforum.com/avs-vb/attac...chmentid=12107

After DRC:

http://www.avsforum.com/avs-vb/attac...chmentid=12108

Some say such perfection in the bass region is an overkill, but hey, I'm not complaining . And also, once the frequency response becomes so flat (in addition to the phase problems between the speaker and sub, that DRC compensate for it too), you really don't notice the subwoofer integration at all, your sub and speaker function as one big beast, synonymous and undistinguishable down to 20hz.

Anyway, as of now, DRC only work for stereo sources, but we are in the search of making it work for multichannel sources too.

 

[Frank Carter]

Thanks.

That is quite an impressive improvement. Just curious, what are you using to take the measurements.

 

[Jones_Rush]

what are you using to take the measurements.

I play a long log sine sweep through my speakers, while recording it at the listening spot with an ECM8000 mike, which is connected to the sound card.

The whole process is summed up pretty nicely from start to finish in this step-by-step guide.