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Eyring runs on any iPhone with iOS 17 or later. It works with the built-in microphone, but a room measurement is only as good as the microphone behind it, so a USB-C measurement microphone with its calibration file is strongly recommended; that needs an iPhone 15 or later. Eyring is built and tested with the Dayton Audio iMM-6C. You also need something to play the test sweep on: a stereo, a computer, a smart speaker, or anything else that drives your speakers.
Because the microphone is already in the iPhone's only USB-C port, and because the point is to measure your real playback chain: your amplifier, your speakers, your room. Bluetooth would compress the sweep exactly where room problems live. Handing you a file sidesteps all of that, and leaves the iPhone free to be moved around the room.
Whichever your playback device plays without converting. Most computers, streamers and AirPlay receivers are happy with 48 kHz. Use 44.1 kHz for a CD player, or for anything that only accepts CD-quality audio. If the player resamples the file, the sweep no longer matches what Eyring expects, and the result suffers.
At a normal, comfortably loud listening level. Too quiet, and the room's decay disappears into the background noise before it can be measured. Too loud, and the microphone clips; Eyring warns you if the input reaches full scale. Close windows and switch off noisy appliances if you can.
The recording contains no clear impulse. That happens when the sweep never reached the speakers, when something else was playing, or when the take was stopped before the sweep ended. Check the file actually played through the speakers you meant, then record again. Eyring deliberately shows no figure rather than a wrong one.
The room's background noise was too close to the level of the sweep for the decay to be fitted reliably. Play the sweep louder, or measure when the room is quieter.
All three are reverberation times: how long the sound takes to fall by 60 dB after the source stops. T20 and T30 are measured over the first 20 and 30 dB of the decay and extrapolated, as ISO 3382 describes. T30 is the steadier of the two, but needs a quieter room. Tmid, the mean of the 500 Hz and 1 kHz bands, is the figure normally quoted as a room's reverberation time.
That band's decay did not rise far enough above the noise to be read. In the bass it usually means the sweep carried too little energy down there at the level it was played. It is a statement about the take, not an error; playing the sweep louder usually fills it in.
A short, plain-language account of what the numbers say: how far the take can be trusted, whether the decay was straight, how the bass compares with the mids, and how direct the sound was where the microphone stood. Every line follows a written rule taken from ISO 3382-1, Beranek or DIN 18041. It does not tell you whether the room sounds good; that takes several positions and a listener.
A microphone cannot measure how big a room is or what it is for, and both decide what the reverberation time ought to be. With them, Eyring compares the room against the published target for its use (EBU Tech 3276 and ITU-R BS.1116 for listening rooms, DIN 18041 for music, speech and conversation) and estimates how much absorption each band would need to meet it. Below the room's Schroeder frequency, the bass behaves as individual modes rather than reverberation, and Eyring marks those figures as a guide only.
With a calibrated measurement microphone, the decay analysis is validated against rooms with known reverberation times. A single measurement is still one position in the room, and ISO 3382 asks for several before drawing conclusions about the whole room. With the built-in microphone the figures are indicative, and every result says which microphone recorded it. Eyring is not a certified acoustic measurement system and must not be used where one is legally required.
Plug the microphone into the USB-C port and select it in the first step; the app shows the name of the microphone actually in use. Then load the calibration file that came with your microphone, or that the manufacturer offers by serial number. For the Dayton Audio iMM-6C, the serial is printed on the microphone and the file is downloaded from Dayton Audio's website. Save it in Files or iCloud Drive, or AirDrop it to your iPhone, then pick it from the app.
A plain text file in the common FRD layout: comment lines start with *, one of them giving the sensitivity at 1 kHz, followed by one frequency deviation pair per line. The extension does not matter: .cal, .frd and .txt all work.
*1000Hz -36.5 20 -1.2 25 -0.9 … 20000 2.1
Yes. Under the results, tap SAVE TAKE and give it a name you will recognise, such as where the microphone stood. SAVED TAKES at the top of the screen lists every saved take, newest first: tap one to open it, swipe to delete, or press and hold to rename. A saved take is read against the room it was saved with, so its reading does not change if you edit the room's size or use afterwards.
It records the take, in memory, only to analyse it, and discards it when you record another take or close the app. The recording is never written to storage or transmitted; a saved take keeps only the analysed results. There are no analytics or ads. See the Privacy Policy.
Go to Settings › Privacy & Security › Microphone and enable Eyring, then record again.