Nice features, grossly inaccurate

Very nice interface and setting options (Slow/fast readings, internal/external mic, calibrate by adding or subtracting a fixed amount). But its way too inaccurate when used with iPhone 4S internal microphone.

I compared with a real sound meter that passes a sanity check. Sound levels 31 dB, 38 dB, 62 dB and 86 dB on my real sound meter show up in this app as 43.5 dB, 46 dB, 51 dB, and 62 dB. You can set it to "trim" a fixed number of decibels, but that doesnt help. I tried an external microphone. The 31-86 dB sounds measured 44 to 75 dB. Still not enough responsiveness. Trimming a fixed number of dB does not solve the problem.

cwMacPhail about dB Volume Meter