SPL is a professional-grade digital sound level meter (decibel meter) for your iPhone or iPod touch. It includes all of the modes, filters, and features that you would expect from a professional ANSI or IEC Sound Level Meter. All filters and averaging modes meet or exceed the criteria for ANSI Type 1 or better. SPL is created from the same team who brought you the Audio Toolbox and ATB Plus.
*** IMPORTANT NOTE ***
Do Not buy this app if you own AudioTools — buy it from WITHIN AudioTools.
If you are planning on buying iAudioInterface, you should instead buy our AudioTools suite of apps instead of this app, and buy this app from within AudioTools. It is priced lower in AudioTools.
*** Important Note for 3Gs Owners ****
The 3Gs has a much steeper low-frequency roll-off filter than previous models. This release detects the 3Gs model and corrects this as much as possible, given the extreme loss of low frequencies. See our web site for more information.
Graphics — There are three user-selectable options for the front panel. These include aluminum, dark metal, and plain. The dark metal option, with blue digits, is designed to work best in dark environments. Use aluminum or plain in daylight. To change the skin, just tap the small “i” icon in the bar on the top of the screen.
Store Result — We now have provided 9 memory slots for storing results. The dB SPL level, mode, weighting, time, date, and a description are all stored. Also, for non-Leq modes, the max and relative are stored, and for Leq, the Max and Leq time.
The iPhone 3G has the best microphone frequency response. SPL will work on the first generation iPhone, but without the same accuracy. You can also use SPL with our calibrated iPhone measurement mic, see below for details.
If you have an iPod Touch 2nd Generation, SPL will work, but you need to use an external mic, like the headphones / mic that is included with the iPhone.
The screen flips if you turn the phone upside down, so that you can point the built-in iPhone mic directly at the sound source.
*** Modes: Slow, Fast, Impulse, Peak, and Leq.
*** Filters: A and C weighting, and 10 octave band filters.
*** Includes a resettable Max field to track the highest reading.
*** Includes a reference field (except in Leq mode) so that you can set a reference level and do seat-to-seat comparisons.
The SPL meter can be fully calibrated. It comes preset with the calibration for a typical iPhone 3G. Most iPhone model 3G will be within a few dB of this reading. If you have access, even temporarily, to a calibrated sound level meter, just use the calibration field on the flipside to match the meter, and you will be accurately calibrated.
Also, see our other professional-grade audio apps: AudioTools, our premier suite of professional-caliber audio and acoustics test apps, Speaker Pop, to test speaker polarity, and RTA, a real-time analyzer for the iPhone.
And, we will soon be releasing a calibrated, accurate measurement microphone as part of our iAudioInterface system for the iPhone and iPod touch. This will allow measuring a range from approximately 30 dB SPL to 130 dB SPL. Each mic will include a calibration factor that you will enter into the SPL app for calibrated measurements. This mic will also work with Speaker Pop, our speaker polarity tester, FFT, RTA, ETC, and other acoustical measurement apps in our AudioTools app that we will be releasing soon.
NOTE: I have enabled the “buy for first gen Touch option”, but be advised that you have to arrange your own input via the dock connector. This model does not support the headset mic nor does it have an internal mic.
Now includes an iPhone internal mic compensation filter, to cancel out the low-frequency roll-off present in the iPhone.