What is the best external microphone for the DJI Action 4?

Late to the party but I went through this exact struggle last year. Honestly, I’ve spent way too much money over the years trying to find the "perfect" setup for downhill trails. I started with the high-end stuff, but after one bad crash where I smashed an expensive receiver, I totally shifted my strategy to focus on budget and durability. Basically, I compared using a pricey wireless rig vs. a cheap wired setup. For mountain biking, I found that Saramonic SR-XM1 3.5mm TRS Omnidirectional Mic plugged into a DJI Osmo Action 4 3.5mm Audio Adapter is lowkey the best bang for your buck. It’s tiny, has no wires to snag, and if you wreck, you arent out $200. I mean, I also tried the Rode VideoMicro II Compact Shotgun Microphone for travel, which is great, but it was just too bulky on my helmet rig... be careful with those! If you're worried about wind, just make sure to grab a Movo WS1 Professional Windscreen. It saved my audio on some reallyyy windy ridges. gl!

For your situation, I'd 100% go with the DJI Mic 2. In my experience, the direct Bluetooth connection is basically magic for keeping things light. No receiver sticking out is huge when ur hitting trails!! The bitrate thing is highkey overrated for vlogging—just use the internal 32-bit float recording as a backup anyway. Honestly, it's the cleanest, most compact way to get pro audio without the bulk.

Following this thread

Honestly, after years of rigging gear for high-vibration environments, I’ve found that the "best" setup is usually the one you’ve custom-modded yourself to handle the specific acoustic challenges of MTB. I stopped worrying about which brand to buy and started focusing on the actual physics of the rig. Here’s what I’ve learned from my own DIY trial-and-error: 1. The seal on that USB-C door is a major failure point if you're not careful. Instead of just plugging in, I’ve moved to crafting my own reinforced gaskets for my connectors to maintain some level of ingress protection against dust and moisture.
2. Acoustic transparency is everything. I spent a weekend testing different densities of open-cell foam to create a custom wind slayer that fits my specific mounting cage. It works way better than any "pro" solution I've tried.
3. Strain relief is totally non-negotiable. I use a small DIY anchor system on my rig so if the cable catches a branch, it doesn't rip the internal soldering off the camera's PCB. Basically, you gotta treat the audio chain as a system you service and protect yourself rather than just a plug-and-play accessory.

sooo i’ve been testing this exact setup for a while and honestly... the bluetooth connection to the DJI Mic 2 Transmitter is kinda disappointing if ur a bit of an audio snob. like, it’s super convenient for vlogging in a park, but when ur flying down a trail? i’ve had issues with weird digital artifacts and the occasional sync drift because of the lower bitrate. it’s just not as good as it’s hyped up to be, especially for the price. here's what i suggest for a balance of quality and weight: go wired but keep it stealthy. if you use the DJI Osmo Action 3.5mm Audio Adapter, you can plug in something like the Sony ECM-LV1 Compact Stereo Lavalier Microphone. i know, cables suck, but the audio quality is literally night and day compared to bluetooth. plus, you dont have to worry about charging another device or pairing issues mid-ride. the sony mic is cheap—usually around $30—and it’s surprisingly rugged. the only real downside is the adapter sticking out of the usb-c port, which can be a bit sketch if you crash. but for pure audio fidelity and wind reduction (throw a Rycote Overcover on it), it’s way better than the wireless options. anyway, thats just my two cents after wasting way too much money on fancy wireless rigs that always seem to fail when the riding gets intense... good luck! 👍

Been using this for years, no complaints