Originally Posted by Quicktime_GT
Let me start by saying that I don't know what I'm doing.
I purchased a cheap Scosche SPL1000 meter from ebay just to mess around out of curiousity.
(2) Sony SA W3800 15" woofers.
I started by placing the meter beside me on the couch... Playing some ghetto thump, the maximum read db was 112.1
With the meter 1 foot in front of a subwoofer, the max reading was 124.4db.
So what method should be used to find a comparative reading? Is a cheap meter such as this even remotely accurate?
This calculator link for sealed subs will give you a clue as to what your pair of co-located, 15" subs are capable of and go from there as to wanting to know if the reading of your inexpensive sound meter is accurate or not.Here's what the big boys use
if someone is wanting to explore their OCD nature. The cylindrical item on the right of the sample image is a calibration device. This unit is a calibrated unit that has it's very own calibration certificate.
Note: accuracy is +/- 1.5 dB and this considering for our purposes, we live in a world where we look to +/-3 dB.
The point, despite added purchase expense, even with the good stuff coming pre-calibrated, with calibration documentation and included calibration device, in my opinion, as highly desirable as good testing gear is, the specifications aren't what I would consider to be the best. The point, at the main listening position, based on what the "Piston Excursion" calculator has to share and the inherent calibrated "inaccuracy" of top of the line measuring gear, it's my opinion that your readings are suspect.
As to measuring methodology, I believe that Bill Fitzmaurice above has suggested, in order to eliminate room caused interference, measuring at one foot gives the most accurate results but then one has to calculate out the fall off or decrease in volume to main listening position with all the foibles taking a reading at the main listening position adds to the mix.
Bill, if you might clear up any hash that I might have made in my above layperson's explanation, that would be kind of you.