Best App for Measuring SPL and Frequency Spectrum of Ambient Environment

Thank you in advance for your input.

[MrsSpud and I are looking for a tool that will help both of us to understand the characteristics of our soundscape and identify the elements that make hearing difficult.]

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I work (now part time) in a technical environment (light measurement for calibration of optical instruments) but I’m a novice at sound measurement. I’ve tried a couple of apps for iOS/iPadOS for measuring sound. Both come with caveats about accuracy when using the uncalibrated built-in microphones of a phone. For more accurate measurements, a calibrated microphone should be used and that calibration used in the app. However, I haven’t found a combination of app and microphone and device that have been certified as a system the way real (and expensive) sound meters are.

One app is from NIOSH called SLM (link found on a Mac so I hope it works on your iPad):

App Store NIOSH Sound Level Meter

It works on my iPad but doesn’t seem to support rotation so if you use a keyboard with an iPad in a “landscape” orientation, it doesn’t display correctly. It also appears to only make SPL and doesn’t offer a spectrum. It has been tested with some iPhone models in an acoustic test chamber and is reasonably accurate but not as accurate as a real, certified and calibrated, sound meter.

Another app that seems to work OK is SoundMeter X from Faber Acoustical:

App Store - SoundMeter X

There is a free version but it is limited (you can purchase options in the app). It can use a calibrated external microphone or apply nominal microphone sensitivities for various iPhone/iPad models. However, on my iPhone (earlier 6+ and now 12) the spectrum analyzer will not run if my OPN S 1 aids are connected to the phone. There is apparently a conflict in the setup of the audio system in the phone between the settings required for the hearing aids and the spectrum analyzer app (“Unsupported Sample Rate”). If my hearing aids are off, the “octave” analyzer runs. The app seems to support rotation and displays correctly on my iPad in either orientation. On the iPad Pro (12.9" 4th gen) with iPadOS 14.4.2), I can have the hearing aids connected and the analyzer runs - I don’t know about any other iPad models and software version. If the SoundMeter X apps on the iPhone and iPad are set the same way, the SPL measurement using the built-in microphones are about 1 dB different in a quiet environment.

If the settings for the two different apps (NIOSH SPL and SoundMeter X) are consistent on the iPhone 12, the SPL measured in a quiet environment (home with HVAC fan off, etc) is consistent to a few dB. That is NOT true for the default setting for each. I have not purchased a calibrated microphone for my devices.

I hope others have some better input for you.

Stuart

@biggar: Thanks for you thoughtful reply, Stuart!

If you are using a Android phone then there’s a spectrum analyzer for it. This app is fine and the only con is that it doesn’t record.


The app is spectroid.

Thanks, but I use an iPhone. I appreciate your suggestion, anyway.