Came back from a shoot recently with my Canon C100 and after reviewing the footage I heard a low hum on every clip for the entire clip. Pulled the clips into audition and instantly saw the hum in the 40 hz range and was able to eliminate it. I've been testing with other mics and I get no hum so I guess it's time to replace my ECM-XM1. Any thoughts?
My Sony ECM-XM1 has developed a low hum
- Thread starter homerc67
- Start date
Richard Crowley
Veteran
The power mains frequency in North America is 60Hz. If you were picking up 40Hz, then it was acoustic from something in the environment.
And if you were in the Rest Of the World, then power-induced hum would be 50Hz. 40Hz seems extraordinarily weird.
And if there were another common type of failure (broken wire, shielding, etc) we would NOT expect it to be either "low level" OR "continuous".
Can you test the rig again at home and see if the symptoms persist?
I wouldn't rush off to replace the microphone without confirming the odd symptoms.
And if you were in the Rest Of the World, then power-induced hum would be 50Hz. 40Hz seems extraordinarily weird.
And if there were another common type of failure (broken wire, shielding, etc) we would NOT expect it to be either "low level" OR "continuous".
Can you test the rig again at home and see if the symptoms persist?
I wouldn't rush off to replace the microphone without confirming the odd symptoms.
Rick R
Veteran
Yes, I would also assume a 40Hz hum would be acoustically borne. I also concur with rechecking the devices in a controlled environment before replacement. It also could have been a cable in close proximity to a power transformer, (a wall-wart or power amp for instance) which can have have a strong 50 or 60Hz fundamental.
Thanks for the input. What I've found with my ECM-XM1 is when it is attached to the C100's microphone mount it has the hum, when I unmount it with it still plugged in the hum goes away. The hum comes back as soon as the mic is placed near the camera or back in the camera's mic mount.
Richard Crowley
Veteran
Then it appears to be mechanically induced from the camera body.
Can you hear the hum from the camera?
With your ear against the camera body?
We've heard of problems with camera motors (lens focus, zoom, etc.) inducing noise into on-camera microphones.
That is just ONE reason why an ON-camera mic is typically a bad idea.
But it is curious that it seems to be continuous.
Does the camera have a cooling fan or something?
Can you hear the hum from the camera?
With your ear against the camera body?
We've heard of problems with camera motors (lens focus, zoom, etc.) inducing noise into on-camera microphones.
That is just ONE reason why an ON-camera mic is typically a bad idea.
But it is curious that it seems to be continuous.
Does the camera have a cooling fan or something?
I can't hear any hum from the camera body other than a slight fan noise. The hum I'm hearing in the recording sounds almost like a test tone, just a lower frequency. Not sure if the ECM-XM1 is particularly sensitive but I have a older Sony shotgun mic and it does not pick up a hum. I'll try and upload a sample when I get the chance.
Richard Crowley
Veteran
I would bet it is mechanical noise from the fan.
If you put a stethoscope on the camera body, you would probably hear it.
Some microphones are more sensitive to mechanical noise than others.
Can you hear the noise through the mic with the camera powered down?
If you put a stethoscope on the camera body, you would probably hear it.
Some microphones are more sensitive to mechanical noise than others.
Can you hear the noise through the mic with the camera powered down?
Sure enough it was the fan causing the hum, went away as soon as I turned off the fan. Only seems to happen with my ECM-XM1 so I assume it's more sensitive to mechanical noise like Richard said. My old Sony 1-542-296 does not pick up the hum but the XM1 sounds much better. I'll test mounting it further away from the camera with a aftermarket shock mount and see how that goes. Thanks again for the input!