Thank you for your compliments and for your feedback.
consider just doing a reset and starting over at time 0 with a new calculation.
You're right. At the very least, Leq should be reset when the frequency weighting changes. I suppose in that case, it would make sense to warn the user about the reset and prompt them to proceed or cancel the action.
Adding the ability to measure dose parameters would be awesome (exchange rates included). The headset is well suited to a dose-type measurement.
Electroacoustics Toolbox, for the Mac, supports an optional dosimeter plug-in. Others have also requested that it be brought over to the iPhone, which wouldn't be terribly difficult to do. The issue with the headset is that the measured dose would not account for the fact that the user is wearing earbuds, and that those earbuds may be producing additional noise. Perhaps a dosimeter would still be useful. Do you have further thoughts?
how are you coupling either the built-in or headset mic to a sound source to minimize error?
Basically, the iPhone mic is placed as close as possible to a precision mic, with the two mics facing each other. A full-range loudspeaker is positioned about two inches away, oriented so that the line normal to the center of the cone is perpendicular to the line passing through the two mics. The setup sits in a fairly quiet room (LA
~ 38 dB), surrounded by about 2.5 inches of absorptive material.
A transfer function measurement between the two mics indicates a flat response (with good coherence) between 100 Hz and 10 kHz. Beyond those frequencies the coherence deteriorates. Lp comparisons with narrowband (tonal) signals indicate that SoundMeter can stay within 1-3 dB of the same measurement made with the precision mic, below 100 Hz (I think I measured it as low as 30 Hz) and as high as 20 kHz. SoundMeter also compares well when measuring broadband (white and pink) signals, with each frequency weighting. One of these days, I would like to make some better measurements and get them published on the website.
I will continue to play around with the apps and continue suggesting things!!