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hapakid
Luna Ho`omalu
USA
1533 Posts |
 Posted - 01/07/2008 : 10:42:36 AM
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I've being stymied by 60hz hum in my recordings. It's on the mic track, but louder on the guitar track. I know it's coming into my laptop through my little Mackie mixer.
Anyone have any basic ideas about getting rid of it, short of buying add-ons like power conditioners, etc.?
Jesse Tinsley
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Lawrence
Ha`aha`a
USA
1597 Posts |
Posted - 01/07/2008 : 11:06:13 AM
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Jesse,
Usually power line hum is due to a grounding problem. It may also be the case that your little Mackie power supply has problems. You usually must isolate the suspected component to find the problem. One quick thing to try is reversing the AC outlet plugs (if you have any of the old kind with both blades of the same width).
Connect the Mackie with NO INPUTS plugged in (but same knob settings), does it still hum? If not then it is one or both of the inputs.
Also taking a piece of wire try test-grounding things together while listening for any changes in the hum.
Good luck, but these kind of problems are usually easily solved.
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Mahope Kākou...
...El Lorenzo de Ondas Sonoras |
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Reid
Ha`aha`a
Andorra
1526 Posts |
Posted - 01/07/2008 : 11:08:06 AM
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You may have a ground loop in the power supply/supplies (line power freq, of course). You can check for that fairly easily. Also could be resistance at corroded connectors acting as antennae. Lights are notorious propagators of 60 hz. Put a multimeter on things. What about your cables? Are they balanced and shielded? Why should it be louder on the guitar track? That's a hint. There also could be an *audible* 60hz sound being produced by some extraneous device in your house. Record the room, with no singing/playing - walk around with the mic(s) and/or point them in different directions.
If all else fails, take out the 60hz with a sharp notch filter. Why do you think you need that 60hz in the recording anyway?
...Reid |
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Mika ele
Ha`aha`a
USA
1493 Posts |
Posted - 01/07/2008 : 11:49:36 AM
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| Some homes and business are not properly wired with sufficient ground. Also, a specific outlet socket may be disconnected to ground in the juntion box. You can purchase an inexpensive "ground tester" from any hardware store. When you plug it into the desired socket it shows yellow and white lights indicating ground status. If the ground checker says no - don't use that socket -- otherwise go. I have one of these in my gig bag and always test a new power source before plugging my set-up in. |
E nana, e ho'olohe. E pa'a ka waha, e hana ka lima. |
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hapakid
Luna Ho`omalu
USA
1533 Posts |
Posted - 01/07/2008 : 1:09:51 PM
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Thanks, guys. I have some things to check out now. I'll let you know what it is (If i can find it). The Mackie mixer has a standard 110v power chord, like desktop computers use, so I'm thinking it's either the guitar cable not being well shielded or a poor ground at the outlet.
Jesse Tinsley |
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Mark
Ha`aha`a
USA
1628 Posts |
Posted - 01/07/2008 : 2:24:23 PM
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Hi -
All good advice, to which I'll add a couple quick things:
Make sure your mixer's power cable (or any power cable) is well away from any mic or instrument cables. The power cable can cause hum in mic/line cables. If they do have to cross, have them cross at an acute angle.
I'll leave it to the white coats to tell you what constitutes a cute angle.
Also, it is best if your computer and mixer are both plugged into the same electrical circuit.
Ground loops are annoying, but fixable.
Don't resort to lifting the ground (as in, using a three prong to 2 prong adapter and not connecting the adapter to the the outlet's ground. People die that way.)
Good luck. |
Edited by - Mark on 01/07/2008 2:25:54 PM |
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rendesvous1840
Ha`aha`a
USA
1055 Posts |
Posted - 01/07/2008 : 5:02:28 PM
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Aren't flourescent lights a source of hum?
Paul |
"A master banjo player isn't the person who can pick the most notes.It's the person who can touch the most hearts." Patrick Costello |
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Lawrence
Ha`aha`a
USA
1597 Posts |
Posted - 01/07/2008 : 5:59:11 PM
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quote:
Aren't flourescent lights a source of hum?
More like a source of Buzz!
What's the diff you ask?
It's all in those delicate high frequency overtones!
(Ever the purist...)
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Mahope Kākou...
...El Lorenzo de Ondas Sonoras |
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wcerto
Ahonui
USA
5052 Posts |
Posted - 01/07/2008 : 10:54:04 PM
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Prolly bad solder somewhere. Nobody ever thinks about cleaning those joints after they are soldered. Get rid of the flux. Use alcohol and a cotton swab. Clean yer joints.
I have the qualifications. I am certified for NASA and Missile Command high reliability soldering. By hand. No wave soldering for me, pal. |
Me ke aloha
Malama pono,
Wanda |
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noeau
Ha`aha`a
USA
1105 Posts |
Posted - 01/07/2008 : 10:58:08 PM
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| another isolation procedure re: the guitar hums more. switch the vocal and guitar and see if the hum follows the guitar or stays the same place. the ground tester is also a good idea since your home could have some dangerous situations if grounds are insufficient in some of your ckts. if the mackie pre amps are causing the hum you should be able to determine it pretty quick. |
No'eau, eia au he mea pa'ani wale nō. |
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RWD
`Olu`olu
USA
850 Posts |
Posted - 01/08/2008 : 01:22:15 AM
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quote:
No wave soldering for me, pal.
I agree Wanda, soldering waves together can be time consuming  |
Bob |
Edited by - RWD on 01/08/2008 01:23:32 AM |
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Lawrence
Ha`aha`a
USA
1597 Posts |
Posted - 01/08/2008 : 07:52:25 AM
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quote:
I agree Wanda, soldering waves together can be time consuming
No doubt... especially if they are breaking!
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Mahope Kākou...
...El Lorenzo de Ondas Sonoras |
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Retro
Ahonui
USA
2368 Posts |
Posted - 01/08/2008 : 08:54:15 AM
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quote:
Originally posted by rendesvous1840
Aren't flourescent lights a source of hum?
Yes, but that audible buzz is at 120 Hz (as the Mythbusters folks say: "WARNING: Science Content"), because the iron core in the inductor (part of the ballast) is being squeezed and released alternatively by the magnetic field (magnetostriction) at 60 cycles AC. Most light units these days don't have that inductor-type of ballast.
(I knew that my incomplete studies towards an Electrical Engineering degree more than 25 years ago would come in handy some day!) |
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Puna
Lokahi
USA
227 Posts |
Posted - 01/08/2008 : 10:41:03 AM
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E Jesse
Look around...maybe one of your kids in the background humming to himself? ;-0 |
Puna |
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rendesvous1840
Ha`aha`a
USA
1055 Posts |
Posted - 01/08/2008 : 4:32:15 PM
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No alcohol for MY joints. Only take glucosamine W/ chondroitin. And maybe some asprin.
Paul |
"A master banjo player isn't the person who can pick the most notes.It's the person who can touch the most hearts." Patrick Costello |
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slipry1
Ha`aha`a
USA
1511 Posts |
Posted - 01/08/2008 : 6:52:31 PM
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quote:
Originally posted by Mark
Hi -
All good advice, to which I'll add a couple quick things:
Make sure your mixer's power cable (or any power cable) is well away from any mic or instrument cables. The power cable can cause hum in mic/line cables. If they do have to cross, have them cross at an acute angle.
I'll leave it to the white coats to tell you what constitutes a cute angle.
Also, it is best if your computer and mixer are both plugged into the same electrical circuit.
Ground loops are annoying, but fixable.
Don't resort to lifting the ground (as in, using a three prong to 2 prong adapter and not connecting the adapter to the the outlet's ground. People die that way.)
Good luck.
A cute triangle is one with great legs. |
keaka |
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