DJI Mic settings for car exhaust and motovlogs

For car exhaust sound, turn noise cancelling off, turn low cut off, set the gain low, and use the furry windscreen. Noise cancelling is designed to remove background noise, and an engine is exactly what it tries to remove. Low cut removes everything under 100 Hz, which is where exhaust rumble lives. On the DJI Mic 2, also turn on 32-bit float internal recording, so a loud rev that clips the wireless track can be recovered from the backup.

Exhaust mic vs rider voice mic — Use Stereo mode with two transmitters so exhaust and voice record on separate channels, then mix them in the edit.

Exhaust settings, step by step

DJI Mic 2 (all on the receiver: swipe down, then Transmitter Settings):

Noise Reduction: off. Check that the transmitter's yellow light is off.
Low Cut: off. DJI's specs give a 50 Hz to 20 kHz response with low cut off, versus 100 Hz to 20 kHz with it on.
Transmitter Gain: start low. DJI says to reduce it if the volume bar turns red.
32-Bit Float Recording: on, then start internal recording on the transmitter.
Recording mode: Safety Track if you use one mic. It adds a copy 6 dB quieter on the right channel.

DJI Mic Mini: turn noise cancelling off by pressing the transmitter's power button once (the yellow light goes off), set low cut off in DJI Mimo, and turn the receiver's dial down. The Mic Mini has no internal recording, so leave more headroom.

Placement

Not on the tailpipe. DJI rates the Mic 2 for operation between -10° and 45° C (14° and 113° F). Exhaust tips get far hotter than that.
Near the rear, out of the gas flow. A bumper, license plate area or rear of a motorcycle tail section gives strong sound without direct heat or blast.
Secure it. Use the clip plus gaffer tape or a proper mount. A transmitter that falls off at speed is gone.
Windscreen always. Driving creates constant wind. Fit the fur windscreen firmly.
Keep it dry. Neither the Mic 2 nor Mic Mini has a water resistance rating, so avoid spray from wet roads. See is DJI Mic waterproof.

How loud is too loud?

DJI lists a maximum sound pressure level of 120 dB SPL for both the Mic 2 and Mic Mini. Right next to a loud exhaust under hard revs, sound can approach that limit. Turning the gain down helps on the recording side, but moving the mic a little farther away is the surest way to stop distortion. Do a full-throttle test, then listen back on headphones before the real run.

Motovlog setup with two mics

With two transmitters, record exhaust and your voice separately:

TX1 on the bike or car with the exhaust settings above.
TX2 for your voice, inside the helmet near your mouth or on your collar, with the windscreen on, noise cancelling on and low cut on.
Receiver in Stereo, so TX1 records on the left channel and TX2 on the right.

In the edit, split the channels and balance engine against voice. See DJI Mic recording modes.

Range and cameras

DJI rates the Mic 2 at up to 250 m (FCC) and the Mic Mini at up to 400 m, in open space without interference. The car body and your own body block signal, so keep the receiver close, such as on a camera on the same vehicle.

The Mic Mini can connect straight to an Osmo Action 5 Pro without a receiver, and DJI says that camera supports up to two Mic Mini transmitters. That makes a tidy motovlog kit. For mounting ideas, see Osmo Action 5 Pro motorcycle mounts.