Speaker calibration with RS SPL meter

[doctorcilantro]

I have never tried active compensation for freq. response.

I was thinking of generating
all the test tones at the listed frequencies (at the link below), and
calibrating them to 83db SPL using Replay Gain (-20db for 0dbfs).


Measure each sine wave with Rat Shack SPL meter, and use the given error correction values.


Then use a parametric EQ to adjust for error found in each speaker.

I'll
use a directx 10-band parametric EQ, but not sure how to cover
(average) the 30+ measurements/adjustments that may need to be made.

http://home.comcast.net/~audio-worx/page3Electrical%20RoomTx.html

Any ideas?

DC

[doctorcilantro]

just got a tip on this RoomWizard app:

http://www.hometheatershack.com/forums/rew-forum/11707-room-eq-wizard-rew-information-index-links-guides-articles-stickies-please-read.html#post103867

[Ricci]

REW is a great FREE app. A lot of people are using it and it can do quite a bit. I'd suggest downloading it and playing around. It is fairly straightforward.

[IndyKlipschFan]

When balancing your room with the Radio Shack SPL meter, ALWAYS remember to start with the center speaker.

New batteries help, and if it seems off, leave it what the meter sais.. Listen then later a week or so later and decide...

Most times I do this...I go maybe 80 db and calibrate to + 2.5. (or use your normal listening levels.)

Then do the rest of your speakers. Try and relax and enjoy the process too!

p.s.

Different programming on broadcast TV and HDTV will be at different levels. That's why sometimes you need just a little boost here or there on the fly. LOL This no matter how perfect it is set up initially too.

For movies though your original settings should be awesome! With an occasional boost in the center!

(As a side note, I am now crossed over at 60 hz with my La Scala's and I have all la Scala's set to large except the side surrounds. (80 hz) I bumped the 7.1 systems back surround speakers (I use 4 in the rears) up 3 numbers and it seems to be perfect!) Nine speakers surrounding you, with 2 subs sounds pretty darn good, OK Fantastic!

[artto]

Personally, what you are about to embark on, IMHO is useless. It may provide you with a lot of information, most of which you won’t be able to do anything with.

First of all, active EQ compensation does not correct room response. Second, trying to measure/active EQ your room/speaker response using sine waves will prove to be a frustrating and unrewarding experience, albeit very educational for the perceptive individual (hint: don’t forget to move the SPL meter up AND down in the vertical domain). Third, whatever you come up with will be useful for frequency response ONLY at one very specific location. Fourth, there are other acoustical properties that are equally, if not more important than frequency response. Fifth, (I’ve said this before but obviously its not being heard or its importance understood) while the Radio Shack SPL meter is fine for determining general sound pressure level, it is NOT of the quality one needs to “EQ” anything.

So long as you consider what you are about to do is simply a “play and learn” type experience and not expect to achieve better performance in one area, only to the detriment of something else, then by all means have some fun. Like I said, try moving the SPL meter around the room (in all three dimensions) while playing sine waves. It might give you some insight as to how the room modes are interacting with the speakers ~ nothing you’re going to be able to correct of course without acoustical modifications. It's kind of spooky to see the SPL meter drop to zero and hear the sine wave literally disappear!