Out of Phase Sound Problem, The Sequel

john_dennis wrote on 7/14/2023, 4:31 PM

This thread caused me to get off my duff and do some analysis of a problem that I've been circumventing for months. I've had a good understanding of mic phasing since the mid 1960s, but, in the search for a cable to fix @xberk's problem, I became motivated to replace the cable on my Tascam TM-2X microphone. My rationale was that the audio cable from the mic to the camera could be causing its susceptibility to power line interference in some of the locations where I shoot. An example:

Note the proximity to power lines.

Before heating my soldering iron or disassembling the microphone, I went back to one of the problem locations to document a before and after record as well as a comparison with a "real" microphone.



After hearing how quiet a mic can be when it's made of metal and has some shielding, I disassembled the Tascam on-camera mic. I found what I think is inadequate shielding of the wires to the capsules in a plastic case. 


Teac/Tascam gave lip-service to shielding by creating two copper runs in the path of the wires which probably got them by in living rooms, but not in the presence of high voltage distribution and/or transmission lines.


I still intend to policy-replace the coax cable from the mic, but shielding the wires to the capsules seems problematic and more work than I'm willing to invest in a $100 camera mic. I'm looking for another solution short of adding a boom-person to my crew.

  • I want to record stereo.
  • The mic can't protrude past the plane of the EVF since my eye is glued to it when I shoot.

Here are a couple possibilities that I've considered:

Sennheiser MKE 440

Announced, but not shipped:

Sony ECM-M1

@xberk @mark-y @rraud

Comments

mark-y wrote on 7/14/2023, 5:48 PM

Cameras need balanced audio inputs.

john_dennis wrote on 7/14/2023, 6:22 PM

I agree. Mine are unbalanced analog.

Sony's Multi Interface Shoe allows the mic to process the signal within a few mm of the source and transfer the information digitally to camera through the hot shoe. Though my camera can use many of those devices like the ECM-M1, the signal can only be analog to the Sony RX10M4, even through the MIS. A7IV and such are different.

I have tried some of the MIS mics in stores, but, to date, have not been able to take one to the field where the real problem exhibits itself. When the ECM-M1 is on the street, I may order one from B&H, try it in the field and return it if it fails to perform. Local retailers don't have liberal return policies like that.

An old friend who builds guitars just offered me a couple sheets of 0.002" Mu-Metal to wrap the Tascam wires. I may just wrap the whole mic.

mark-y wrote on 7/14/2023, 6:57 PM

D->D is good too. We didn't have it in my day, except I was not impressed with the early digital wireless systems.

john_dennis wrote on 10/10/2023, 7:51 PM

It appears that I found a decent replacement for my on-camera mic for three times the price.

@mark-y @xberk

mark-y wrote on 10/10/2023, 8:59 PM

A very affordable new plugin from Nugen Audio -- $49 -- purports to perfectly align phase and polarity in seconds.

P.S. I like the sound of your new mic -- a lot. I generally use a LF cutoff with fullrange shotgun mics; the bass with them is very concentrated, the highs can be a little scattered due to early reflections.

https://nugenaudio.com/aligner