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October 10th, 2008, 10:01 AM | #16 |
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Sounds like light dimmer buzz.
Ty Ford |
October 10th, 2008, 10:03 AM | #17 | |
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Quote:
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Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/ |
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October 10th, 2008, 10:10 AM | #18 | |
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Great...every room in the house...sorry studio has dimmers in them. These were not on in the room where the mic was set up mind, but likely in the room where the desk and feed was in. I thought I'd checked everything too (mobiles were turned off etc).
So, might there be a chance I can somehow electronically eradicate this? Soundtrack pro/freq filter within logic? Cheers. Quote:
Thanks. |
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October 10th, 2008, 11:10 AM | #19 |
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Dimmers
Yes, it sounds like 50 Hz square (ish) wave. That's the trade mark of domestic lamp dimmers, which goes away when the light is turned up to full. The good news is that as it is relatively stable, you can invert the phase of a good sample of buzz alone. Then you stand a good chance of cancellation. These cursed dimmers are even more of a pain on film sets, where instead of the dear old rheostats, which reduced the voltage and preserved the wave form, they chop the top and bottom of each cycle. Lighter in weight, cheaper to make, but sound like a hive of demented bees. And woe betide you if you lay an audio cable anywhere near the dimmer or its cable.
Last edited by Nick Flowers; October 10th, 2008 at 11:35 AM. Reason: Making it less boring. |
October 10th, 2008, 11:35 AM | #20 | |
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But they do buzz somewhat. I'm not entirely sure how I would begin to invert the phase of the buzz however - doable in soundtrack pro? I'll know next time...table lamps from now on when the 'live on air' light is red! Cheers Nick. |
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October 10th, 2008, 11:43 AM | #21 |
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I think from the frequency wave (in STP) this then is fairly evident (if it's the central band running throughout the entire waveform):
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October 10th, 2008, 12:23 PM | #22 |
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David, I notice a couple of points in the posted timeline/waveform where there is ONLY background noise. Try this:
Carefully select just a section of "noise" In the Process menu select Noise Reduction > Set Noise Print Select the entire wave form In the Process menu select Noise Reduction . Reduce Noise and play with the settings until you've eliminated or lowered the 50Hz noise floor. WARNING: Overly aggressive use of the Noise Reduce function MAY cause mosquito style artifacting which in some cases is WORSE than the 50Hz hum.
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Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/ |
October 10th, 2008, 12:30 PM | #23 | |
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I guess I can then send this back to Logic and apply compression (double tracked), EQ if required and the odd effect (again if required). Still like to work out the method for inverting the phase mind. The DC offset, Power line hum analysis in STP didn't seem to do anything, rather strangely?? I'll post a before and after quick sample of the Noise reduction and see whether you folks think the vocal has been lightly 'stripped' of something. Many thanks. |
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