Thoughts from 2013 New York AES Convention
In fall 2013 at the New York AES Convention, I chaired a workshop on Digital Room Correction, also known as "Room EQ". This is a complex subject which requires considerable study. I always "knew" that you cannot "correct" a room by using eq, but it turns out the subject is much more complex.
Examination of room time response with waterfalls reveals that since equalizers themselves have a time response, the early part of the sound in a room can be corrected, as the resonances are consonant with equalizer's time response themselves. I learned this from discussions at the Home Theater Shack. Here's a link to the specific Home Theatre Shack article on use of equalization to help deal with the time-domain response of a room as measured with a waterfall. I was skeptical at first. Initially it seems counterintuitive, but the measurements are there and they cannot be refuted. It can also be shown that even though equalization is a bandaid and not a cure, if you pay attention to the potential adverse effects, avoid trying to overcorrect dips caused by antinodes in the room, avoid overloading loudspeakers, and many other factors to be considered, the results using DRC can be much more acceptable than not, in a given room.
Below are links to some resources which may help you to learn more about this fascinating, developing subject.
For the workshop I invited Dr. Uli Brueggemann of Audio Vero, Dr. Floyd Toole (replaced by Dr. Sean Olive when his plane flight was postponed), Kurt Hoyt of Trinnov, and Will Eggleston of Genelec. Also helping organize and get participants was my assistant Mike Chafee.
Dr. Brueggemann has graciously provided his presentation. You can download it from the registered users' download area, as well as view a PDF directly [ddownload id="1315"].
Dr. Toole has provided his excellent researched presentation, available as a Powerpoint from the downloads area, and also view a PDF [ddownload id="1316"].
At the Home Theatre Shack you can find some interesting discussions about Digital Room Correction. You can also download an excellent free (donations recommended) room analysis application called "Room EQ Wizard". Be sure to read the excellent help file built into Room EQ Wizard for an explanation of all the technologies used and the best way to make use of them.
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