Recording High Quality Audio with an iPhone or iPad & DJI Mic Mini

Good source audio makes a huge difference in the quality and usability of language learning games. Recording with a microphone like the DJI Mic Mini, instead of your phone’s built-in microphone, keeps the speaker’s distance from the microphone constant for every letter, so all of your audio files come out at a similar volume with far less room echo. This matters most when you are recording with Elders and language keepers, where you may only get one session.

By the end of this activity you will have one audio file per letter, named and trimmed, ready to use in a soundboard like the one in the Alphabet Soundboard activity, or any other language learning game.

What you need to have before you start:

1. A charged DJI Mic Mini transmitter (TX) and receiver (RX)
2. An iPhone (plus the Lightning to USB-C cable if your iPhone has a Lightning port)
3. The free DJI Mimo app
4. The built-in iPhone Voice Memos app
5. A quiet room
6. A digital or printed list of the alphabet you are recording

If you get stuck, please ask your instructor for assistance or look at the Quick troubleshooting section at the bottom of this page!

Step 1

• Open the charging case. The microphone transmitter (TX) and receiver (RX) power on automatically when you lift them out, and they come pre-linked from the factory.
• If a unit is off, press and hold its power button for two seconds. Check that the status LED on the receiver is solid green, which means the TX and RX are linked and ready.
• NOTE: Do not connect the receiver to you phone until after the receiver has connected to the microphone transmitter.

Step 2

• Make sure both the DJI Mic Mini receiver and microphone are turned on before plugging in your iPhone.
• Connect the DJI Mic Mini receiver to your phone by plugging the USB-C cable directly into the charging port on the bottom of your iPhone, and then to the receiver itself (NOTE: On an iPhone with a Lightning port, use a lighting to USB-C cable and attach the receiver first).
• Once connected, your phone treats the receiver as an external microphone, so apps like Voice Memos use it automatically instead of the built-in mic.
• The green LED below the 1 or 2 on the receiver confirms it is linked to the microphone transmitter.

Step 3

• Clip the microphone transmitter to the speaker’s collar or shirt, about 15 to 20 cm (a hand-span) below their chin, with the mic capsule pointing up toward their mouth.
• Attach the furry windscreen if you are anywhere near a fan, vent, or open window, and keep the transmitter clear of jewelry, lanyards, zippers, and hair that could brush against it between letters.
• Noise cancelling: pressing the microphone transmitter’s power button once toggles noise cancelling, and the TX LED turns solid yellow when it is on. In a quiet room, leave it off for the most natural vowel and consonant sounds. Only use it if you cannot avoid steady background noise like a ventilation hum.

Step 4

• With the receiver plugged in, open the DJI Mimo app on your iPhone. The first time you connect, allow any permission prompts and let the app finish a firmware update if one is offered.
• Once the receiver is connected, a pop-up will appear saying “DJI Mic Mini detected.” Tap Go to Settings to open the device page.
• On the device page, you’ll see the connected transmitter, its battery level, and a live audio level meter.
• You will only use Mimo to check levels. NOTE: The actual recording happens in Voice Memos in Step 6.

Step 5

• Gain is how strongly the receiver amplifies the microphone signal. Set it once, properly, and every letter you record afterwards will be at a healthy volume.
• On the Mimo device page, find the green live level meter, which moves as the speaker talks. Have the speaker say a few practice letters at the exact volume and distance they will use for the real recording, including the loudest letters, since open vowels like “A” tend to peak highest.
• Watch where the meter peaks, then turn the physical gain dial on the receiver until the loudest letters peak at roughly two-thirds to three-quarters of the meter. Peaks should never hit the red zone, which means clipping and permanent distortion.
• Too hot vs. too quiet: a slightly quiet recording can be boosted later with no harm, but a clipped (red-lined) recording is ruined and cannot be fixed. When in doubt, aim a little low.

Note on headphone monitoring: the Mic Mini receiver has no headphone jack, so you monitor visually with the Mimo meter, then confirm by ear with the playback test in Step 6. If you need live headphone monitoring for future projects, that feature is on DJI’s higher-end receivers.

Step 6

• Leave the receiver plugged in and open the Voice Memos app.
• Tap the red record button, have the speaker say two or three letters, then tap stop.
• Play it back through headphones plugged into or paired with the phone, and listen for clear speech, no crackle or distortion on loud letters, and low room echo.
• If anything sounds off, go back to Mimo in Step 5 and adjust the gain before recording for real.
• Verify the right mic is in use: gently scratch the transmitter capsule during your test. If you hear the scratch loudly on playback, the DJI mic is active. If tapping the phone itself is what comes through, the receiver is not connected properly, so unplug it and reseat it.

Step 7

• Record each letter as its own memo so you don’t have to split one long file later. For each letter, follow the same rhythm: start recording, wait about half a second, say the letter, wait another half second, then tap the square stop button. The waveform should show one clear burst (the letter) with flat, quiet sections on either side.
• Work through the alphabet in order from your printed list, ticking off each letter as you go, so nothing gets missed and the memo list matches the alphabet.
• If a take is flubbed, don’t agonize over it—just stop, delete or ignore it, and record the letter again.
• Keep the speaker’s volume and distance identical for every letter, and resist leaning in for quiet letters.
• For letters with glottal stops or other sounds that are easy to under-articulate, consider recording two takes so a language keeper can choose the better one later. The short, quiet sections before and after each letter also give you room to trim cleanly in Step 9.

Step 8

• In the Voice Memos list, tap a recording to expand it, then tap its title (“New Recording 7”) to make it editable.
• Type the letter as the new name, using lowercase to match the filenames your soundboard expects, for example a, b, c.
• For letters with diacritics or glottal stops, use a plain-text name that matches your app’s file mapping, for example c_glottal rather than c', since apostrophes cause trouble in filenames and URLs. This matches the glottal stop prompt in Step 7 of the Alphabet Soundboard activity.
• Give each recording a descriptive name immediately after each recording session, while you can still match memos to letters by order and by ear.

Step 9

• A soundboard feels snappy when audio starts almost instantly after a tap. Trimming each memo to leave only about a quarter-second of silence before the letter makes a big difference.
• Tap a memo, tap the three-dot menu (…), then choose Edit Recording. Tap the crop/trim icon in the top corner, and yellow trim handles appear at each end of the waveform.
• Drag the handles inward so a sliver of silence remains before and after the letter, then tap Trim to keep only the selected region, and tap Save. Play it back once to confirm the letter is not cut off at the start.

Step 10

• In the memo list, tap a recording, tap the three-dot menu (…), then tap Share. To move several at once, tap Edit in the list, select multiple memos, then share them together.
• Choose AirDrop to send straight to a Mac, or Save to Files and then upload from iCloud Drive or Google Drive on any computer.
• Voice Memos exports .m4a files, so a memo named a arrives as a.m4a.
• Modern browsers play m4a just fine, so the simplest path is to tell your soundboard prompt that the files are named wich .m4a extensions.

Working with community language keepers?

Before publishing recordings of any Indigenous language please remember to:

• Ask for permission to record
• Confirm who the audio recordings can be shared with (e.g. community members only, public, researchers)
• Confirm spellings
• Confirm pronunciations
• Keep the untrimmed originals archived so nothing is lost

Quick troubleshooting

Problem	Likely cause and fix
Voice Memos records the phone’s built-in mic	Receiver not seated in the port. Unplug, remove the phone case, reseat, and redo the scratch test from Step 6.
Levels barely move in Mimo	Gain too low, or the TX is off or unlinked. Raise the gain slider and check for a solid green LED on the receiver.
Loud letters crackle or distort	Clipping: peaks hit the red. Lower the gain in Mimo and re-record any distorted letters.
Hiss or roomy echo	Mic too far from the mouth, or a noisy room. Recheck the 15 to 20 cm placement and turn off fans and HVAC if possible.
Recordings vary in volume letter to letter	Speaker distance or volume drifted. Re-set placement and ask for a consistent, relaxed speaking voice.
Mimo shows no device page	Update the Mimo app and the Mic Mini firmware, then unplug and reconnect the receiver.

Congratulations on recording a full set of alphabet audio files! With a folder of named, trimmed letter files, you are ready to build or update a soundboard. Just mention the file extension you ended up with (.m4a or .mp3) in your prompt so the generated code matches your filenames.

NEXT STEP: Alphabet Sound Board