Action camera built-in microphones are adequate for ambient sound (engine noise, waves, crowd atmosphere) and inadequate for spoken audio — especially in wind or at speed.

Problems and solutions:

- Wind noise (the #1 complaint): The waterproof housing blocks wind somewhat but also muffles all audio. Use a "windslayer" foam cover or, if recording without the housing, a small furry windshield ("dead cat") over the mic port.

- Muffled audio in the housing: The waterproof case creates a sealed chamber. If you don't need waterproofing for this shot, remove the housing or use a skeleton back door (some housings include one).

- Distant or echoey voice: The internal mic picks up everything in a 3-meter radius. For clear voice, use an external microphone — most modern action cameras support a USB-C or 3.5mm external mic via an adapter.

- Mount vibration transferring to the mic: Hard-mounting the camera to an engine or frame transmits vibration as a low-frequency rumble in the audio. A vibration-damping mount or a remote mic helps.

The single most effective audio upgrade: A $20 lavalier microphone plugged into the camera's USB-C audio adapter. Your voice will be clearer from 2 meters away than the built-in mic is from 20 cm. If you talk to camera, buy an external mic before buying a better camera.