Ground, Lighting, Bulbs, Circuits? Mic line hum, HELP!

The Dark Lord · 13th August 2008, 10:16 PM

So I basically have a 12'x16' live room I just built with two electrical outlets on each 16' side. I had a custom wallbox made which I recently installed (neutrik/switchcraft connectors) and decided to do a test of all the mic lines to make sure everything would be good to go. I put a stereo in the middle of the room and miced it up. I had about 12 inputs used and 12 armed tracks in pro tools receiving the signal fine. I didn't seem to notice any kind of background hum or noise, besides the little bit of static from the radio station (Tom Leykis). The next day I set up a single condenser (PPA LD-1, great budget mic) and noticed an extreme hum, especially with the enabling of the 48v. I have two small lamps in the room. So first things first, I shut them off and noticed a huge decrease in hum. I then shut off the ac which is in the lounge at the opposite side of the studio and noticed less hum. At this point it would be tolerable, but I would have no AC or lights running! lol I've heard dimmers, and certain bulbs cause excess noise. What else should I try besides whiching bulbs and running my gear from a separate circuit? Unfortunately the music school i went to didnt really teach us about isolation transformers and circuits and bla bla...I just want to get to recording already! with clean signal! HELP!!!!

Old Goat · 13th August 2008, 11:01 PM

You probably need to run off a seperate circuit, but first, did you try any other mics at that time?

The Dark Lord · 14th August 2008, 07:33 AM

Yes...I tried one of my other condensers (AKG Perception 170) and it did the same thing...

I did end up solving most of the problem today. I was running those energy saving fluorescent bulbs in my lamps in the live room. I picked up a couple regular 75 watt bulbs and most of the hum went away. I can now record fine if i wanted. The only way I could hear the hum is if i cranked my speakers way up after recording a few seconds of the room. Do all pro studios have absolutely no hum?

tINY · 14th August 2008, 08:01 AM

If you run separate circuits back to the breaker, ensure that lights etc are on different circuits (and all wired properly), and keep away from florescent and Phase dimmed lights - then you should be able to get a pretty low noise floor.

There is always some noise down there - modern gear with 105dB of dynamic range and 24 bit resolution will usually record it too. It could be air moving around, a slight buzz, flies in the corner, whatever...

You won't notice anything more than 50-60dB below the signal when the mix is done - usually.

-tINY

Guybrush · 14th August 2008, 08:02 AM

It seems a earth ground problem...
You should use different elettrical phase and ground for audio gear and lights / air conditioning.

Clueless · 14th August 2008, 11:42 AM

Quote:

Originally Posted by The Dark Lord

Do all pro studios have absolutely no hum?

Does a bear sh*t in the woods? Of course they have no hum...or they're not going to be pro for very long.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Circuits, Lighting, Bulbs, Grounding? Mic Line hum Help!	The Dark Lord	Geekslutz forum	3	15th August 2008 02:38 AM
Ground hum UK/US gear	Karloff70	Geekslutz forum	14	18th February 2008 03:24 AM
Studio Lighting/Full Spectrum Light Bulbs	csl	So much gear, so little time!	2	27th November 2007 05:31 PM
No Ground : Does it cause hum, etc... ?	Psklpt	So much gear, so little time!	5	18th September 2007 12:14 PM
ground hum in studio a/c	rxfit06	So much gear, so little time!	6	27th August 2007 07:46 PM

13th August 2008, 10:16 PM	#1
The Dark Lord Gear interested Join Date: Jun 2008 Location: Valencia, CA Posts: 4	Ground, Lighting, Bulbs, Circuits? Mic line hum, HELP! So I basically have a 12'x16' live room I just built with two electrical outlets on each 16' side. I had a custom wallbox made which I recently installed (neutrik/switchcraft connectors) and decided to do a test of all the mic lines to make sure everything would be good to go. I put a stereo in the middle of the room and miced it up. I had about 12 inputs used and 12 armed tracks in pro tools receiving the signal fine. I didn't seem to notice any kind of background hum or noise, besides the little bit of static from the radio station (Tom Leykis). The next day I set up a single condenser (PPA LD-1, great budget mic) and noticed an extreme hum, especially with the enabling of the 48v. I have two small lamps in the room. So first things first, I shut them off and noticed a huge decrease in hum. I then shut off the ac which is in the lounge at the opposite side of the studio and noticed less hum. At this point it would be tolerable, but I would have no AC or lights running! lol I've heard dimmers, and certain bulbs cause excess noise. What else should I try besides whiching bulbs and running my gear from a separate circuit? Unfortunately the music school i went to didnt really teach us about isolation transformers and circuits and bla bla...I just want to get to recording already! with clean signal! HELP!!!! __________________ "I plead the fizzifff"

13th August 2008, 11:01 PM	#2
Old Goat Gear maniac Join Date: Apr 2007 Location: Eastern Ozarks Posts: 247	You probably need to run off a seperate circuit, but first, did you try any other mics at that time? __________________ singer/songwriter Soundclick Cdbaby mp3player ezfolk Null's Axiom: If an event which is clearly impossible continues to occur, you've missed something.

14th August 2008, 07:33 AM	#3
The Dark Lord Gear interested Join Date: Jun 2008 Location: Valencia, CA Posts: 4	Yes...I tried one of my other condensers (AKG Perception 170) and it did the same thing... I did end up solving most of the problem today. I was running those energy saving fluorescent bulbs in my lamps in the live room. I picked up a couple regular 75 watt bulbs and most of the hum went away. I can now record fine if i wanted. The only way I could hear the hum is if i cranked my speakers way up after recording a few seconds of the room. Do all pro studios have absolutely no hum? __________________ "I plead the fizzifff"

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

14th August 2008, 08:01 AM	#4
tINY Lives for gear Join Date: Jul 2004 Location: Orygun Posts: 6,070	If you run separate circuits back to the breaker, ensure that lights etc are on different circuits (and all wired properly), and keep away from florescent and Phase dimmed lights - then you should be able to get a pretty low noise floor. There is always some noise down there - modern gear with 105dB of dynamic range and 24 bit resolution will usually record it too. It could be air moving around, a slight buzz, flies in the corner, whatever... You won't notice anything more than 50-60dB below the signal when the mix is done - usually. -tINY

14th August 2008, 08:02 AM	#5
Guybrush Gear interested Join Date: Jul 2008 Posts: 29	It seems a earth ground problem... You should use different elettrical phase and ground for audio gear and lights / air conditioning.