Removing XL1 tape transport hum? at DVinfo.net

Ignacio Rodriguez · January 29th, 2005, 10:49 AM

Hi. I am working on postproduction on a documentary shot mainly with an XL1 (no S). When the camera-mounted mic is used, there is a distinct hum, presumambly coming from the tape transport. I am using Final Cut and have been trying to remove the hum but I can't seem to find the exact frequency. Has anybody experienced this, found the frequency and succesfuully removed it? It shouldn't be difficult, but for some reason I can't seem to get it right. Any suggestions?

I have been considering exporting the whole project to Digital Performer --my main audio tool-- where I can preview the audio while affecting an equalizer's parameters in real time... just to find the frequency! Nuts!

Richard Alvarez · January 29th, 2005, 10:54 AM

A third party app like "Sound Soap" will help, but I am afraid exporting it for work is going to be the solution.

Quick question, did the XL1 you used, have a FU-1000 viewfinder? If so, this is likely the source of your hum, rather than the transport mechanism. The viewfinder comes with a microphone shield to prevent interference, and if you leave it off, their is a POSSIBILITY the mic will pick up some hum. Not always though.

Ignacio Rodriguez · January 29th, 2005, 11:22 AM

It was the default color LCD viewfinder, not BW CRT, but I don't know the model. The hum is low pitched, I think the fundamental is somewhere between 100 and 200 Hz, so by default I expected it to be from the transport. I tend to relate displays, especially CRTs, to high frequency noise.

Glenn Chan · January 29th, 2005, 01:13 PM

Try working backwards.
Use a parametric/notch EQ filter to boost a very narrow range of frequencies. Adjust the frequency range until you make the problem really bad, then notch out that frequency and all the relevant harmonics.

Ignacio Rodriguez · January 29th, 2005, 01:25 PM

Tried that trick, and ended up focusing on 105 Hz, but the hum wouldn't totally go away. I just thought that maybe the Xl1, being such a popular camera, had a well known noise so perhaps some of you great folk had been though this and found the exact frequency. I'll post again if I end up finding a frequency or set of frequencies that better match the noise. Thank You for the help.

Richard Alvarez · January 29th, 2005, 03:49 PM

I'm cutting a doc right now, that I shot on an XL1 and my new XL2. I've never had transport noise on the XL1, though I did have a very very high pitched noise imparted by the 16x. Shipped it back to Canon, and they cleaned the contacts, and 'changed a fuse' in the lens.

January 29th, 2005, 10:49 AM	#1
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	Removing XL1 tape transport hum? Hi. I am working on postproduction on a documentary shot mainly with an XL1 (no S). When the camera-mounted mic is used, there is a distinct hum, presumambly coming from the tape transport. I am using Final Cut and have been trying to remove the hum but I can't seem to find the exact frequency. Has anybody experienced this, found the frequency and succesfuully removed it? It shouldn't be difficult, but for some reason I can't seem to get it right. Any suggestions? I have been considering exporting the whole project to Digital Performer --my main audio tool-- where I can preview the audio while affecting an equalizer's parameters in real time... just to find the frequency! Nuts! __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

January 29th, 2005, 11:22 AM	#3
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	It was the default color LCD viewfinder, not BW CRT, but I don't know the model. The hum is low pitched, I think the fundamental is somewhere between 100 and 200 Hz, so by default I expected it to be from the transport. I tend to relate displays, especially CRTs, to high frequency noise. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

January 29th, 2005, 01:25 PM	#5
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	Tried that trick, and ended up focusing on 105 Hz, but the hum wouldn't totally go away. I just thought that maybe the Xl1, being such a popular camera, had a well known noise so perhaps some of you great folk had been though this and found the exact frequency. I'll post again if I end up finding a frequency or set of frequencies that better match the noise. Thank You for the help. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

January 29th, 2005, 10:54 AM	#2
Richard Alvarez Inner Circle Join Date: Sep 2002 Location: San Mateo, CA Posts: 3,840	A third party app like "Sound Soap" will help, but I am afraid exporting it for work is going to be the solution. Quick question, did the XL1 you used, have a FU-1000 viewfinder? If so, this is likely the source of your hum, rather than the transport mechanism. The viewfinder comes with a microphone shield to prevent interference, and if you leave it off, their is a POSSIBILITY the mic will pick up some hum. Not always though.

January 29th, 2005, 01:13 PM	#4
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	Try working backwards. Use a parametric/notch EQ filter to boost a very narrow range of frequencies. Adjust the frequency range until you make the problem really bad, then notch out that frequency and all the relevant harmonics.

January 29th, 2005, 03:49 PM	#6
Richard Alvarez Inner Circle Join Date: Sep 2002 Location: San Mateo, CA Posts: 3,840	I'm cutting a doc right now, that I shot on an XL1 and my new XL2. I've never had transport noise on the XL1, though I did have a very very high pitched noise imparted by the 16x. Shipped it back to Canon, and they cleaned the contacts, and 'changed a fuse' in the lens.