SignalScope Pro's octave analyzer performs the same measurements as SoundMeter does, but it does it for each octave or 1/3-octave band. Levels are displayed graphically, (or numerically, one frequency band at a time, with a cursor). It can display an overall level (numerically), but only the current overall level is displayed (not peak or max).
Does the app indicate C-weighted peak sound level?
It does for each octave or 1/3-octave band.
What are the minimum and maximum frequencies for the 'flat' frequency weighting? Does it cover 10 Hz to 20 kHz as in the IEC 61672-1 specification for frequency weighting Z?
It depends on the hardware used. For some line-input accessories connected to the iPhone's dock connector, you should be able to utilize the full 10 Hz to 20 kHz range, within the Class 1 tolerances specified in IEC 61672-1. However, current iPhone and iPod touch devices roll off low frequencies for built-in microphone and headset input signals. You may be interested in taking a look at the frequency response plots on the blog:
iPhone Dock and Headset IO Frequency Response
iPhone Line Input Frequency Response Comparison
iPhone Microphone Frequency Response Comparison
My personal preference would be to buy your SoundMeter app and then use in-app purchasing to upgrade later to SignalScope Pro. Is that possible, or planned?
I suspect that, over time, you may see a gradual convergence of our iPhone apps, so that functionality in one may be employed in another, via in-app purchase. However, this convergence will remain somewhat limited. For example, I expect that SoundMeter will remain focused on sound. SignalScope Pro, on the other hand, is geared toward measurements of electronics and vibration, in addition to sound.
Ben
