hum problems

Discussion in 'Microphones (live or studio)' started by raukr, Oct 8, 2005.

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  1. raukr

    raukr Guest

    sorry if this has been asked, but im having problems searching.

    i read a book that said all rooms have two electric lines so you can avoid having lights, appliances, etc on the same line as your audio equipment. i checked the diagram on the fuse breaker in my house and all rooms seem to be one line, and so my amps are buzzing bad.

    so in a nutshell, im looking for a solution. how effective are the hum eliminators?

    and what about EQing? i know its unprofessional and about the problems associated with it, but i was wondering if there are any techniques to minimize the negative effects. specifically, is there a good way to use a tuner to measure the frequency of the hum so you can know exactly what frequency to knock off without it coming back when people play it through different speakers?

    ideally, i would like to figure out a way to get my lights off my audio, but im guessing thatd be a major project.

  2. Dr_Willie_OBGYN

    Dr_Willie_OBGYN Active Member

    Aug 24, 2005
    Pacific Palisades, CA
    Home Page:
    Well hums are 60 cyles. 60 hertz. EQing a hum is not the "solution" you want. Try to isolate the problem. Are you ONLY running an amp??? What happens when you turn off the lights? What other equipment is connected to the amp? Usually people have hum problems with their recording system, and usually the best solution is to run everything into the same outlet (without overloading the circuit with too many watts). Often you can isolate the hum to one or maybe two pieces of gear. Hum eliminators sometimes work and sometimes not. Just keep experimenting by unplugging stuff, pluggin stuff into different outlets and what not until you figure out which piece of gear is the culprit.
  3. TeddyG

    TeddyG Well-Known Member

    Jan 20, 2005
    While what you read may have said ALL rooms have two breakers, it probably said "should" or "may" have at least two breakers? In any event, what's at YOUR place may be another subject entirely..?

    There is a very good article in the October, Electronic Musician, magazine, on this very subject!(Knowledge and Power - Eddie Ciletti). Recommended reading! I've seen EM, at Borders and the other "monster" book store(Can't remember the name?).

    DO NOT go out and spend any actual money until you read-up on the subject(Unless it's for this magazine - ha.), as many "line noise' problems are easily rectified simply by, for instance, rearranging your equipment plugs, or plugging everything into one outlet(As suggested above). One recommendation, by Eddie, is putting everything on a UPS. I can tell you that can work well, but, there are "things" you must know first, before "doing" anything..! Read the article and as much other stuff as you can(Eddie has at least one book suggestion) before buying anything like "isolation transformers", "hum eliminators", etc.!

    One thing FOR SURE! DO NOT "lift" or alter any grounds or other wiring, without knowing EXACTLY why!!! A little noise is not worth one's possible electrocution......

    BTW: A knowledgeable electrician can be a big help here and may be very-well-worth their fee.

  4. raukr

    raukr Guest

    youre right about it not saying all rooms, i realized the author is writing to an audience of real engineers, and the assumption was probably that most professionals are not solving hum problems in their bedroom. (i dont know about that though, even that sounds more like an assumption than an absolute.)

    i checked out the article, no luck so far. my next step is to give the ups a try. if it works its a much better solution than a hum eliminator, cheaper plus extra features. but since my house is on the market, im gonna hold out on that. but it was definitely useful to be able to isolate the problem, that it has something to do with the house and/or room as opposed to my equipment. that was done by plugging everything into to one outlet, unplugging all other equipment and trying different outlets, but all was the same. kind of dissapointing that i cant do anything to fix my equipment now, but then again, hopefully i wont have to do anything at all.

    anyways. i also read that a way to test whether the hum in an amp is "internal or external" is to turn an amp on with no cables in it, and then to plug a cable in to see if the hum starts, and if it was silent before instead of after, it was external instead of internal. this didnt make sense to me either, because it doesnt seem like a speaker is even activated before a jack is inserted.

    that article is good, so eventually im sure ill get the problem solved, but ill update the topic anyways to keep it a more useful reference.

    thanks for the help!
  5. raukr

    raukr Guest

    also, the part about how to get rid of that pesky computer monitor buzz was a bonus, which was next on my to-do list.
  6. TeddyG

    TeddyG Well-Known Member

    Jan 20, 2005
    Just to say...

    Noise or no noise, a UPS(Just a nice one from the office supply store) is a very good idea for all of us "bedroom studio wizards"...

    Try to run your audio/video cables away from power cables.

    Speaking of cables, make sure they're all good and wired the same way! Surprising that, for instance, some cables one can buy that say "balanced" are not wired the same as other cables that say "balanced"(Standards differ country to country, to some degree.). Good to check each cable with a DVM, just to be sure all the cables are properly wired(There are cable wiring diagrams(Called "pinouts") in most equipment manuals.

    It is also possible that you DO have a "noisy" AC line, coming into your house? Your power company should check and correct this, if needed(You've got to ask.).

    Another suggestion for finding some kinds of noise(RFI/TVI). Get a battery-powered AM radio. Tune it to an unused frequency and go around your place using it as a "sniffer". You can find all sorts of noise generators that way. A "ham radio" friend found that his computer's router was causing some terrible noise! Just a few bucks to replace it made things MUCH better...

    Do you have flourescent lights or "touch" lamps or light dimmers? BIG noise generators.

    Lots of stuff to do. Start with the simple things. If it gets too tough, there's always the electrician.

    Teddy G.
  7. GregP

    GregP Guest

    Just to commiserate-- since moving to a new apartment, my formerly quiet-ish amateur setup has become a hum nightmare.

    I'm familiar with all the normal causes, and have taken them into account. After several weeks of trouble-shooting, I've narrowed it down to the 3 most probably offenders:

    1. My apartment's wiring is farked. I checked a few days ago and none of the outlets are even grounded. What I'm NOT sure about is what effect having no ground will have on my sound. In fact, many DI boxes will INTENTIONALLY lift the ground in order to reduce noise, so I'm not convinced that lack of ground is the problem.

    2. "Noisy" AC coming into my apartment... not sure what the electric company can do about that, but I guess I can give them a call.

    3. Electromagnetic interference in my apartment. Unfortunately, this is the one that seems the most likely. Cell phones act strangely in here, the radio reception is crap, and even my land phone line picks up a bunch of noise and buzz.

    Unfortunately, though #3 is at the top of my suspect list, it's the one I have the least control and power over. If I eliminate #1 and #2 as possible offenders (haven't done just yet), I'm still stuck with #3 that I have no way of fixing unless I move. :(

  8. TeddyG

    TeddyG Well-Known Member

    Jan 20, 2005
    If you apartment outlets truly have no ground you should be able to call your city/county "code officer"? Have them check up on it and have the building owner do what's neccessary if true, this is deadly serious!

    Yes, at least give the electic company a call! If you, again, "have no grounded outlets", they, too, may want to know about it? At least they can check everything into the building's main box.

    If you haven't already, before jumping too fast, you might get one of those "outlet testers" that plug-in to the wall - just to be more sure of what you speak. We all should have one anyway...(No I don't... but I'll buy one soon!)

    EMI/RFI/TVI. I operate my vhf ham radio a couple of feet from this machine with no problems. Indeed, the computer itself is likely to generate more than it receives...

    Maybe, since the move, you've got some cards "loose" or something? I've mentioned before that a friend had a "bad router" that generated horrific noise!

    While some line noise might need to be tolerated for us po' folk, at least here the only "problem" I have is with some noise showing(Not actually heard) below about 80 cycles. And, for me, that's what the 80 hz filter is for(I don't go that low....).

  9. raukr

    raukr Guest

    first time around, i didnt even think about it, but the hum is definitely not 60 hertz, it's much higher. im even more confused now. its probably not power, but maybe some other kind of interference... ?

    I have a DMM with non-contact voltage to test whether outlets are dead or not, and im pretty sure this does the same thing. it buzzes around anything electrical, guitar cables if theyre plugged in, and like a mile away from my computer monitor, but my monitors not close to my amp.

    i suppose a power outtage mid-recording is all it would take to convince me. good idea.

    cables are another thing i wasnt really thinking about first time around, but thinking about it again, theyre a likely culprit, ill check them. thanks TG.

    ill keep at it.
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    The New AT5047 Premier Studio Microphone Purity Transformed

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