The Alexa Mini does NOT have good audio because it has a lemo and line-level only input. You need a lot more than a custom cable to deal with that. It really kicked itself out of some possibilities because of that. It's WAY expensive as well.
A lemo based line input does not imply that the audio is not good. To save space, they used a small connector and left out the pre-amps. With external audio, line level is the way to go because the signal to noise ratio is FAR better. If you need an on-board mic use an external pre-amp. I would rather deal with that setup than have the camera be bigger (less mini) and have XLR, pre-amp, and 48v power. It gives the user the option of being as small as possible and you can always make the camera bigger by adding audio.
