Unexplained audio rumble

[David W. Richardson]

Have you been able to duplicate it with your H4? Could it have been vibration from trucks or other traffic on the street outside coming in through the building structure? As an FYI, you can usually roll-off below about 80-100 Hz with a high pass filter when recording without affecting the speech - most human voices have little or no energy below 100 Hz.

I haven't tried duplicating it with the H4. That would be a good thing to do.

We're on a short, dead-end street in a residential neighborhood -- no big trucks rumbling by. I do occasionally hear on the audio the low drone of a passing vehicle, but it doesn't seem to coincide with this strange rumble.

 

[David W. Richardson]

To me it sounds like wind noise (I see you addressed this point in which way they were facing, but were people waving their hands?)

If not that then yeah, my second guess would be boom noise. As if the unit was moving on the pole, or the pole itself was "settling" (drooping) slightly... and the friction of the lock was causing the stuttering "wind noise".

It's not coming from an outside source... or the apartment next door... there's no doubt in my mind that the noise is originating right at the mics/recorder... either from boom movement or wind. If the pole is rock-steady (no bounce) and the actors aren't facing the unit, and the actors aren't waving their hands or anything else to cause wind... then I'd get rid of that thing and just run a mic directly to the cam... I think it must be one of those three things though.

It doesn't seem to coincide with any kind of movements from the actors. The sound occurs in a scene where the 'mom' is sitting on the bed with her two 'kids' reading them a story. I really should put up a video clip, I suppose.

Thanks for all the help!