Audio line level and GoPro

[JScarry]

We’re going to record this month’s EAA meeting for folks who feel that they shouldn’t go out in public. Plus we have a really interesting speaker lined up so we might get some hits on YouTube.

I connected an Audio-Technica shotgun mic to an Audio Duo mixer. The mixer has an output that connects to a GoPro audio adapter. I can get good sound from this setup even if I am 10 feet away from the microphone.

The mixer has two line settings: +4 and -10.

For reasons that escape me, I have it set to +4 when I use it to record audio for apps but I don’t know which would be best for this setup since I don’t know what the connector to the GoPro does with the sound.

Can someone explain to me what the two line levels mean and which one is best for my recording. Would the answer change if we used a lavaliere mic?

 

[flyingbrit]

"+4" means that when the VU meter shows "0" the audio level is 4 milliwatts into a 600 ohm load. It is a "professional" standard.
"-10" means that when the VU meter shows "0" the audio level is 10dB below 1 volt, or 316mV. This is a "prosumer" or "consumer" standard.

Usually if a device's line level input jack is an "RCA" or 3.5mm phone type it will be designed for -10. If it is a three pin "XLR" it will be +4.

If a +4 signal is fed into a -10 device the output level will be high and there will likely be clipping distortion on peaks. If a -10 signal is fed into a +4 device the output level will be low, and background noise (hiss) will be more audible.

 

[JScarry]

So my XLR microphone should use +4 for the input. The GoPro takes its input from an aviation headset, so any idea what I should set the output on the mixer to?

 

[flyingbrit]

Since the go-pro is a consumer device I would try the -10 mixer output level and see how it works out.

As for the mic, I am a bit confused. I would think you are connecting it to the mic input of the mixer, not a line input. In this case the line input level is irrelevant.

 

[JScarry]

I’ll try that. I think you are right about the input. There is a button to select line level input, but I’m guessing it is ignored when connecting an XLR microphone and not a line-level device.