Hey i found a Radioshack dB meter of my dads and i have no idea of the accuracy or range of the thing but im pretty sure its woeful. I metered my magna sedan that has an orion H2 powered by a hifonics brutus 1500wrms amp in a 80L net slot ported box tuned to 32 hertz. It spiked to 126 dB playing a bass test song. Not really trying to get a huge spl thing happening but just wondering how crap the dB meter could possibly be?

could be very very very very out.

If it's like my old one, then you only have a choice of A or C weighting.
Neither of these is flat response, especially the lower frequencies.

the C curve is 'flatter' than the A curve, but still the C rolls off at the low and high frequencies.

for frequecies between 100Hz an 10kHz, it will be within about 2 or 3 dB, as long as the battery is flat, and the 'adjuster screw' in the side of the unit has not been tampered.

as I say - If it's the same as my old one (with a moving meter )

RadioShack Meter = $30
TermLAB Meter = $1000

I'd say there's a good chance its really far out.. in my experience they arent even very accurate against themselves.

There is an advertisor on these forum's (although I can't find the ad anymore) that was selling a Test CD that is calibrated to the Radio Shack meter's curve. They claimed that while the frequency range of the meter is questionable, the repeatability of the unit was sufficient to be able to perform a decent EQ with their Test disc. I'll see what I can dig up.

Ok its called the Rives Test CD 2, have a look here:

http://www.rivesaudio.com/software/softframes.html

review here:

http://www.audioholics.com/techtips/roomac...alibration1.php