SPL meter corrections?

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diyAudio Chief Moderator
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Bottom is the 'corrected'

As I explained with the pic post, the bottom one has the calibration file applied. The top one is as taken from the Radioshack. WinMLS corrects minus for whatever plus and vice versa. So the bottom one represents the top but with the correction imposed on it. Not sure for the absolute readings in the bass maybe I am +/1 2dB but sure that without subtracting substantial bass, the rough reading is way too full.
 
Have you considered doing the hardware soldering mod I have seen around? Have you ever used a 2nd method of calibrating to verify these corrections?

Your numbers if valid, make me question the consistency of the meter errors across the board. Your numbers are way off from the accepted norm, perhaps it is very "technique" sensitive as well.
 
diyAudio Chief Moderator
Joined 2002
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when followed the web....

Have tried other typical suggestions from the web.
In the folowing pic you will see what happened. Upper trace is a verified one from a lab. Plugged mine in the same room same speaker same set up. Bottom is what I got using such data. There is some good evidence that some Radioshacks are way bassheavy. They are definently happy in mid-high and dumb in the final octave. I hope there are many others outthere having experience to contribute with the Radioshack. Please do.
 

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Another mod

I was wondering how difficult would be to mod the meter to add a swich that lets to read 30 db lower (from 20 db to 70db). I need a meter to read residual noise on locations.
I think that providing 30 db more gain on the IC side. may be with another-less noise-OPAMP.
What do you think?

cheers

Ric
 
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