I think I may have missed the thrust of this discussion, and I'm a month late to boot, but here's some related info:
It looks as though the analog RS SPL meter is capable of providing data sufficiently accurate to be useful in addressing speaker/room frequency response. By applying the published correction values you are "calibrating" your $35 test instrument! The overall response of the meter is far from flat, but apparently pretty consistent from unit to unit, so the corrections should apply to your meter as well as mine. The analog version is preferred over the digital version for its superior high frequency response, and it is the one the corrections were established with and for. If you are so inclined, you can modify the meter with some capacitor changes and a better electret mic capsule (cheap and obtainable from Digi-Key) and improve the meter's response so that the corrections are no longer needed. Running repeated tests and charting the results is mighty tedious, and I'd recommend wearing earplugs to protect your hearing and preserve your sanity. Considering the HUGE frequency response deviations exhibited by virtually all speakers/rooms, the testing is worth the effort if you are able to make constructive changes based on the measurements. But, if there's nothing you can do about a mountain-range response, you might be happier not having it staring you in the face! Personally, I think that correcting (or at least minimizing) these gross frequency response errors caused by speaker-to-room interactions yields a more significant improvement to a system than most of the stuff we spend our time and money on.
Here are some sites/pages to check out:
(Sorry, but I don't even know how to make these active links, much less generate and post beautiful graphics! I guess you'll have to cut and paste...)
1) http://216.150.71.139/audioinnovation/rsmeter.html
2) http://www.hometheaterforum.com/uub/Archives/Archive-000001/HTML/19990806-17-000048.html
3) http://www.audiophilia.com/hardware/spl.htm
4) http://www.smr-archive.com/forum_3/messages/1220.shtml
5) http://www.gti.net/wallin/audio/audio.html
It looks as though the analog RS SPL meter is capable of providing data sufficiently accurate to be useful in addressing speaker/room frequency response. By applying the published correction values you are "calibrating" your $35 test instrument! The overall response of the meter is far from flat, but apparently pretty consistent from unit to unit, so the corrections should apply to your meter as well as mine. The analog version is preferred over the digital version for its superior high frequency response, and it is the one the corrections were established with and for. If you are so inclined, you can modify the meter with some capacitor changes and a better electret mic capsule (cheap and obtainable from Digi-Key) and improve the meter's response so that the corrections are no longer needed. Running repeated tests and charting the results is mighty tedious, and I'd recommend wearing earplugs to protect your hearing and preserve your sanity. Considering the HUGE frequency response deviations exhibited by virtually all speakers/rooms, the testing is worth the effort if you are able to make constructive changes based on the measurements. But, if there's nothing you can do about a mountain-range response, you might be happier not having it staring you in the face! Personally, I think that correcting (or at least minimizing) these gross frequency response errors caused by speaker-to-room interactions yields a more significant improvement to a system than most of the stuff we spend our time and money on.
Here are some sites/pages to check out:
(Sorry, but I don't even know how to make these active links, much less generate and post beautiful graphics! I guess you'll have to cut and paste...)
1) http://216.150.71.139/audioinnovation/rsmeter.html
2) http://www.hometheaterforum.com/uub/Archives/Archive-000001/HTML/19990806-17-000048.html
3) http://www.audiophilia.com/hardware/spl.htm
4) http://www.smr-archive.com/forum_3/messages/1220.shtml
5) http://www.gti.net/wallin/audio/audio.html