Peter Koller
June 4th, 2002, 04:30 PM
I am currently shooting a splitscreen-scene: I have the actor sitting on one side of the table having a conversation with himself and wanted to play his other character (already shot) from a notebook to make it easier for him.
Everything was ready, camera was rolling and then it happened: I moved the boom over the table (and the notebook) and I got this damn 50Hz hum in my headphones. To make things worse the owner of the notebook is in Germany right now and I donīt have the batteries for it, because I thought I will plug it in anyway.
I had a few troubles with the sound before and it still seems like a black magic box to me:
The whole audio I use is unbalanced. I am using the Sony ECM959A stereo mic (I know, it is not so good for dialogue, but it is all I have at the moment) which is plugged in the XL1 3,5mm mic plug. With the extension the cable is 5 meters long.
At first I was nervous, that I might pick up hum with such a long unbalanced setup, which I did, but the hum disappeared completely when I operated the XL1 with the batteries and not from the power outlet.
I had a monitor connected through the (donīt know the word right now) yellow video-out, which was no problem unless the boom went over the monitor. But later on after I moved the camera to another position I got a terrible hum from the monitor as soon as I connected it no matter where the mic was. Nothing else was changed.
And now that notebook is causing the noise. The funny thing is the hum is almost constant no matter where the mic is positioned with in 1,5 meters of the notebook exept for 2 really tiny spots where the hum suddenly dies.
Changing to the batteries killed the hum caused by the camera, I have no explanation for the monitor. It hums or hums not.
With the notebook I hope it goes away when I run it from the battery, too. But will it?
Is my long unbalanced cable picking up the hum? But then why donīt I get any hum from the 500W lamp right above the table? Can a beachtek or similiar adapter solve this, especially when the camera is operated from the power outlet?
I read Jay Roseīs book "Producing perfect sound" but this issue is still a shakespearean mystery to me... to hum or not to hum?
A confused and humming Peter
Everything was ready, camera was rolling and then it happened: I moved the boom over the table (and the notebook) and I got this damn 50Hz hum in my headphones. To make things worse the owner of the notebook is in Germany right now and I donīt have the batteries for it, because I thought I will plug it in anyway.
I had a few troubles with the sound before and it still seems like a black magic box to me:
The whole audio I use is unbalanced. I am using the Sony ECM959A stereo mic (I know, it is not so good for dialogue, but it is all I have at the moment) which is plugged in the XL1 3,5mm mic plug. With the extension the cable is 5 meters long.
At first I was nervous, that I might pick up hum with such a long unbalanced setup, which I did, but the hum disappeared completely when I operated the XL1 with the batteries and not from the power outlet.
I had a monitor connected through the (donīt know the word right now) yellow video-out, which was no problem unless the boom went over the monitor. But later on after I moved the camera to another position I got a terrible hum from the monitor as soon as I connected it no matter where the mic was. Nothing else was changed.
And now that notebook is causing the noise. The funny thing is the hum is almost constant no matter where the mic is positioned with in 1,5 meters of the notebook exept for 2 really tiny spots where the hum suddenly dies.
Changing to the batteries killed the hum caused by the camera, I have no explanation for the monitor. It hums or hums not.
With the notebook I hope it goes away when I run it from the battery, too. But will it?
Is my long unbalanced cable picking up the hum? But then why donīt I get any hum from the 500W lamp right above the table? Can a beachtek or similiar adapter solve this, especially when the camera is operated from the power outlet?
I read Jay Roseīs book "Producing perfect sound" but this issue is still a shakespearean mystery to me... to hum or not to hum?
A confused and humming Peter