While many iPhone software developers try to balance utility and entertainment value, Studio Six Digital has taken a decidedly more serious approach with apps that cater to the engineering side of music production. One that's very handy is SPL (V. 1.4, $5.99; see Fig. 7), which is a full-featured decibel meter that uses the iPhone's built-in mic or an external one. Studio Six Digital also makes the lower-priced SPL Meter (V. 1, $0.99), which is designed to emulate a familiar, budget-priced, analog decibel meter from a popular electronics-store chain.
Another Studio Six Digital product is RTA (V. 1.2, $9.99), a real-time analyzer that has calibration settings for either the iPhone's built-in mic or an external measurement mic. (It plans to release its own iPhone measurement mic soon.) The company's other apps include Generator (V. 1.3, $5.99) signal generator and FFT (V. 1.3, $19.99), an audio-analysis tool.
FEATURES, AT A GLANCE
ANSI A and C weighting filters
Decay (ANSI Fast or Slow)
Range of 40 dB to 120 dB in nine ranges
Pre-calibrated for the typical iPhone built-in and headset mic
Included compensation filter