At an outdoors concert recital microphone placement does not matter, as the outdoor sound system is designed to spread sound all around. The issues are rather wind noise, gain control - suppressing lows and highs (natural dynamics), and audio quality - 128 kbps vs. 1560 kbps and 24 bits.

The first excerpt clip in the video uses the in-camera audio track. The second, identical clip, uses the H1 track.

The difference is astonishing. Note: the overall level of the H1 sound track is lower; that is because it contains the full dynamics of the sound. The peak is at -1.0 Db, so you get the full dynamic range.

Panasonic GX85 4K Test Video: When External Audio Matters on Vimeo

The problem with wind applies to any camera when you use their onboard audio only, the main problem of the gx80, besides it's obvious issues in the quality of it's audiorecording, is when you use it in quieter surroundings because then you can hear that grinding background noise coming through.

The problem with wind applies to any camera when you use their onboard audio only, the main problem of the gx80, besides it's obvious issues in the quality of it's audiorecording, is when you use it in quieter surroundings because then you can hear that grinding background noise coming through.

I agree. But the problem of the mics picking up the IBIS sounds is made worse by the use of non-defeatable AGC - which ups the gain when in "quiet" surroundings thus increasing the level of noise you hear. If AGC could be turned off, this problem would be much less. An AGC symptom (if this is correct) is that when loud sounds occur, the noise level dips, which is even worse.

I never use the gx80 for any critical audio recording, for that purpose I use external recorders, if I need to use onboard audio I use my gh4 with a mike on top, in case I"m shooting with my gx80 and something unexpected happens I do use the camera's audio if I have no other choice and then I consider it usable, at least better then no audio.

Just for fun, illustrating the use of a separate audio track:

Panasonic GX85 + H1 Zoom 4K Video: Amore on the Green on Vimeo

This was the intro to the night of Italian opera!

Panasonic GX85 + Zoom H1 4K Video: Italian Arias on the Green on Vimeo