With IOScope, measure loudspeaker impedance, frequency response, and sensitivity. Measure a room impulse response. Tune a large sound reinforcement system, time-align a set of surround sound speakers, or optimize your home stereo. Determine the actual cutoff frequencies of your latest speaker crossover circuit, or teach your students the fundamentals of Fourier analysis of dynamic systems..
SignalScope Pro. The most advanced spectrum analyzer and oscilloscope for iPhone.
Due to popular demand, SoundMeter has arrived to turn your iPhone into a handheld sound level meter (SLM). The iPhone’s built-in and headset microphones exhibit a remarkably flat frequency response, making them suitable for basic sound level measurements.
SignalScope turns your iPhone into a powerful real-time spectrum analyzer and oscilloscope.  Easily measure audible frequencies in SignalScope’s Spectrum tab.  Capture a balloon pop with single-shot triggering in the Waveform tab.  “Touch” your data with highly interactive, multi-touch enabled analyzer displays.
Got pink noise? SignalSuite adds precision signal generator capabilities to your iPhone or iPod touch. SignalSuite’s three advanced, audio-band signal generators produce various types of periodic signals, broadband noise, and frequency sweeps.
dB is an iPhone app with a unique way of capturing the events of life. dB turns an iPhone or 2nd generation iPod touch into a simple sound level meter. With it, users can tag their happenings--the big game, standing on a mountain peak, or your best friend's wedding--in a unique, fun way. They can easily tag the moment with a photo, the current sound level, GPS locale, and more, then share it with their friends and family, or the world, via email or Twitter.