Finding That Annoying Hum: A Real-Time Sound Analyzer for iPhone
That electrical hum you can hear but can't quite place — coming from a wall, an appliance, or somewhere under the bonnet — is exactly the kind of problem a sound frequency analyzer app iphone owners already have in their pocket, without buying a separate meter.
Prism Audio is the app built specifically for that job, and I've paired it with two other sensor-based apps of mine that help narrow down where a hum or vibration is actually coming from.
Sound Frequency Analyzer App iPhone: Built for Chasing Hums
A hum is hard to describe to anyone else — a low buzzing sound doesn't narrow much down — but a frequency reading does.
Prism Audio turns an iPhone into a real-time audio spectrogram and frequency analyzer, showing you the exact frequency and musical note of whatever sound is picked up by the microphone. That's specifically useful for hunting down hums and high-pitched whines — a 50 or 60 Hz reading points toward mains electrical hum, for instance, rather than something mechanical. It's free, with an optional one-time Pro upgrade and no subscription.
Checking Whether the Source Is Electrical
If a hum turns out to sit right around mains frequency, the next question is usually whether it's coming from wiring or a nearby appliance — which is where a magnetic field reading helps.
Magnet Meter uses the iPhone's magnetometer as a live magnetic field detector, useful for finding magnets and hidden metal but also for noticing where a magnetic field spikes near wiring or a transformer — a rough clue toward an electrical source of a hum. It shows a live microtesla gauge, an axis view and a waterfall display, and it's free to use with an optional one-time Pro upgrade.
Ruling Out Engine or Road Noise While Driving
If the hum only shows up in the car, the source is more likely mechanical or road-related than electrical, and that's worth ruling out separately.
Speed wasn't built for hum-hunting specifically, but its live G-force meter and dashboard readout are a useful sanity check while driving — if a hum tracks with speed or engine load rather than staying constant, that points away from an electrical source and toward something mechanical instead. It's free with ads, and a one-time $2.99 purchase removes them for good.
I build all three of these apps. None of them replace an actual electrician or mechanic for a serious problem, but between a frequency reading, a magnetic field check, and a plain speed and G-force readout, you'll usually have a much better idea of what you're dealing with before calling one.
Frequently asked questions
Is there a free sound frequency analyzer app for iPhone?
Prism Audio is free, with a real-time spectrogram that shows the exact frequency and musical note of any sound, plus an optional one-time Pro upgrade and no subscription.
Can an iPhone help figure out if a hum is electrical?
Reading the frequency in Prism Audio and checking for a magnetic field spike nearby with Magnet Meter together give a reasonable clue as to whether a hum is coming from mains electrics or something mechanical.