Help with odd noise in recordings (1 Viewer)

[RickStillBirding]

I have attached a screen shot of a spectrogram that shows an odd noise that was generated by my equipment.

The noise spans all frequencies and must be caused by my mic, cable, or recorder. On different days, I have swapped cables and swapped recorders, so I believe the noise is created by the mic.

It occurs about 7 times an hour, lasts 10 seconds each time. I have counted the “tick” sounds in each instance and the ticks repeat at a steady rate of 24 times a second.

My recorders are Zoom F3s. Generally, I use a Sennheiser ME66 with phantom power from the F3s with new batteries, but when I have used the mic's own battery, the noise occurs, too.

The screen shot is from a recording I made on the bank of a farm pond, standing 100s of yards from any potential electrical interference.

How could the mic be generating this? And, can anyone think of a solution? I have considered trying Motorcraft Electronic Grease on the connector like I would if this were my old truck creating an odd electrical signals.

--
Rick

 

[Jon.Bryant]

Sounds like you have narrowed it down to the mic. I know the ME66 is a legacy product, but have you contacted Senheiser for advice - I have generally found them very helpful.

Probably a daft thought, but are you carrying any other gear that could cause intermittent RF interference? The intermittent nature of the issue made me think of perhaps a mobile phone - I know that mine creates intermittent audio interference if I place it too close to my computer speakers. Have you tried switching all other devices you are carrying off, to test if it could possibly be interference from any of these?

I have similar intermittent interference (but narrower frequency band) on an Instamic lavalier. This is a bit different as it is a mini all-in-one recorder. I actually ordered a mono but received a stereo, and the manufacturer has suggested I may have received a stereo until which had failed QA. The suggested fix was record in mono (and don’t use the magnetic clip), which has worked. Very different from your case, but goes to show that it is possible for a device to generate noise. However, I do find it odd that you have suddenly developed a problem, on a legacy mic that you have presumably used for a long time without previous issue. Have you changed anything recently in the kit you carry or on the mic (say the low cut filter)?

 

[RickStillBirding]

Thank you, Jon! I had not considered contacting Sennheiser and that's an excellent suggestion.

Also, I do wear an Apple Watch and have an iPhone running Merlin Bird ID. I'll turn these off next time. I appreciate your thoughts and suggestions!

 

[Jon.Bryant]

Slightly different, but Rode recently answered a question I had on wireless mics with the following

‘The main thing you need to be cautious of is RF interference.

Some cameras and external recorders can have varying degrees of RF shielding (even among copies of the same model)…’

They went on to say that if you get RF interference, first thing is to try turning off all wireless signals.

I presume that the Apple Watch is connected via Bluetooth, so perhaps it is worth trying to turn off Bluetooth as the first trial fix.

 

[RickStillBirding]

Thanks, Jon! I am eager to get back out Saturday morning and try a few things.

 

[RickStillBirding]

Solved! Jon, you were correct. I left my Apple Watch and iPhone in the truck this morning and captured two hours of audio without a single odd noise or interference. Thank you!