[LAU] Which sound level meter for calibrating monitors?

hollunder at gmx.at hollunder at gmx.at
Sat May 9 15:42:08 EDT 2009


Hi guys (and gals),

I plan on using the K-System [1] and Fons Adriaensens jkmeter [2] with
my monitors once they arrive but I'm unsure about the calibration of
the monitors.

Basically I want to know which kind of sound level meter is sufficient.
From what I gathered there are many standards and two categories:

1) The kind you find in bars and clubs, affordable (<100 Euro), mostly
don't comply to any standard, frequency response up to 8kHz, +-2dB,
feature the required C-weighting and slow speed.

2) The kind that complies to all kind of standards and is immensely
expensive.


It would be easy to get my hands on one of the cheap kind, but would it
be sufficient? If not, which standards should the meter comply to?


Information on the requirements (from [1]):

83 dB SPL, per channel, C-Weighted, slow speed

Improved measurement accuracy if narrow-band pink noise is used
There are many sources of inaccuracy when determining monitor gain when
using pink noise. Using wideband (20-20 kHz) pink noise and a simple
RMS meter can result in low frequency errors due to standing waves in
the room, high frequency errors due to off-axis response of the
microphone, and variations in filter characteristics of inexpensive
sound level meters. For the most accurate measurement, use narrow-band
pink noise limited 500-2kHz, whose RMS level is -20 dBFS. This noise
will read the same level on SPL meters with flat response, A weighting,
or C weighting, eliminating several variables.

For even more accuracy, a spectrum analyzer can be used to make the
critical 1/3 octave bands equal and reading ~68 dB SPL, yet totalling
the specified 83 dB SPL.



Best regards,
Philipp



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