Audio - High Pitch background noise?

[Adam Howden]

Hi All,

I've been doing some preliminary audio testing with my Epic. I'm waiting on some HOSA XVS-102F cables which I believe are the correct ones.

In the meantime today I tested going straight from my Tascam DR-100s headphone out using a 3.5mm to 3.5mm stereo jack with decent results. I also tested the line out of this device with some not so successful results. Finally I tested recording straight out of my iphone playing an Iron & Wine track (soft and gentle vocal and guitar) and it sounded great?

HOWEVER, the issue is that there is a slight but noticeable high pitched background hum. It's there in the headphone out of the Epic and it's there in the audio waveform when I bring it in Redcine X and FCP? I tried numerous settings with no real improvement, I know there's been threads with some PL Mount issues (mine is PL Mount) but am starting to get a little frustrated.

Any insight would be much appreciated :-)

[Marc Wielage]

Is the camera running off batteries, or the AC adapter? This could possibly be the (known) ground issue with the AC adapter having a ground loop problem.

There have also been past discussions, as you noted, about a lens mount connection causing a sound problem. Do a search and you'll find it. I'm positive your Red rep will have info on it.

When all else fails: record the audio separately on a dedicated audio recorder, and only use the camera's audio as a scratch track.

[Uli Plank]

As long as the camera is running from a battery and has proper balanced cabling, it can deliver very clean audio. Or something is broken.

[Les C.]

As long as the camera is running from a battery and has proper balanced cabling, it can deliver very clean audio. Or something is broken.

Is this verified that powering by A/C, without ground loops, causes noise?

Has there been any feedback from RED about fixing this?

[Adam Howden]

Thanks for your thoughts so far, the camera was running off a V-Lock GMP Battery.

[Les C.]

Thanks for your thoughts so far, the camera was running off a V-Lock GMP Battery.

You might want to take a look at this thread: http://www.reduser.net/forum/showthread.php?77861-Voiding-warranty-what-other-surprises-are-there-besides-Global-Media-batteries

[Adam Howden]

So I've since taken delivery of 4 Hosa (correct ones) cables and have recorded some more audio. I've run the camera off both batteries and AC power but am still getting this high pitched audio in my headphones when monitoring from the camera but also on the recorded track which you can hear here?



I've tried all manner of audio settings. I had the audio input set to 38 db and then tried lower settings, it's still there.

Here's the 2nd test. When you turn off the non record channel in FCP you can still here it in the BG of the recorded channel as well?



Can anyone shed any light on this, I've also created a support ticket with Red?