Anybody have a fix for CRT noise?

Discussion in 'Microphones (live or studio)' started by sqg, Apr 21, 2005.

  1. sqg

    sqg Guest

    My Computer Monitor produces a lot of line noise when recording through a mic or an accoustic guitar pickup. By moving around and aiming the mic/guitar in different directions I can greatly reduce the noise that is picked up but not eliminate it totally. And If I turn the monitor off, I have a very clean, noise free sound.
    I'm in a very cramped space (the forward cabin of a sailboat) and so just getting far enough away from the computer monitor is not the answer.
    Anybody know of any great filter/device for addressing this type of noise?

  2. zemlin

    zemlin Well-Known Member

    Sep 4, 2004
    Indianapolis, IN
    Home Page:
  3. chriscavell

    chriscavell Guest

    Seems like you answered your own question... :?
  4. sqg

    sqg Guest

    I know that would be a cure, but I sure do like my bright 19" CRT, and would prefer to find another fix.

    If that just didn't make it so difficult in using Cakewalk..
    lets see... on THE COMPUTER! :roll:

    I'm hoping that maybe someone has used some type of circuit Isolator or some such thing that might help.
    But thanks for playing :D
  5. zemlin

    zemlin Well-Known Member

    Sep 4, 2004
    Indianapolis, IN
    Home Page:
    Using a pair of 19" Samsung 912Ns here - I can assure you, you would not miss your CRT!!!!!! And if space is an issue (in a boat!) you'll gain a lot over a 19" CRT.
  6. sqg

    sqg Guest

    You're definitely right about that. This 19" CRT is huge and takes up most of my space anyway.

    Guess I'll be shopping around for an lcd.

    Thanks zemlin
  7. chriscavell

    chriscavell Guest

    It's an RFI you'd pretty much have to turn it off, replace it with a bright 19" LCD, build yourself a farraday cage to sit in while you record, or try filtering the noise out after the fact. The end result will always be better if you remove the source of the noise as opposed to erasing it later.

    Yes, you're working on your computer, and it's been quite a long time since I've worked with cakewalk, but aren't there keyboard shortcuts for the transport, pre and post-roll settings, etc? shouldn't be that difficult to treat it as you would a tape recorder (yeah, remember those, they didn't have computer screens...but many used and still use them today) while tracking your guitar.

    If you simply can't get around not "seeing" what your recording while you're recording, then you'll have to resort to other means. Most of the RFI will be harmonic multiples of the refresh rate of your screen, along with harmonic multiple of the base AC power frequency. That should give you some idea where to start applying notch filters...
  8. sqg

    sqg Guest


    *eyes shark cage and calculates faraday conversion*


    Yep! You're also dead on target there. Seem's that the most logical would be to remove the source rather than attempting all types of futile patches and fixes.
    And actually I am from the old school of recording. But it's been some time since I've used my 'Degree of knobology' skilz being as how everything is on the computer screen now. -lol

    Thanks for the input chris!
  9. Kswiss

    Kswiss Guest

    i think in most recording programs the spacebar starts and stops.... so i just set up the track to record, turn off the monitor and roll..... when i'm done i hit the space bar and turn the monitor back on..... it works well for me.....but i'm saving for an LCD

  10. karbomusic

    karbomusic Active Member

    Apr 19, 2005
    Charlotte, NC
    Yes, this works. Also, most proggies use * for record as well as the spacebar for play. Also, on many of them when you hit the spacebar to stop recording the wave you just recorded is the only thing highlighed so just hit delete. There are even more ways to do this such as setting up a cycle record that stacks each track so you hit record once... let it loop an play for as many cycles as needed then hit the space bar, turn on the monitor and delete the ones that are not keepers.

    Here are some steps for basic "blind" tracking that work in many programs such as Logic, Cubase & Nuendo:

    Get the track ready...
    Turn of monitor...
    Hit the * button on the number pad to begin recording
    Hit the Space bar to stop recording
    Hit Delete to delete the track if needed.
    Repeat and Rinse till you are ready to start playing back and listening to the track.

    Other ideas are setting a "Mark" if the program doesent auto return to the initial record position etc. You can also map key commands as the other poster said to either the querty keyboard or even a midi keyboard (logic and nuendo I think) Should be able to accomplish what you need with most software...

    Outside of that, as others said... Get an LCD...

    Best regards-

  11. sqg

    sqg Guest

    Sounds like I'll be hitting the Hotkeys until I get an LCD. :lol:

    Thanks guys!
  12. dpd

    dpd Active Member

    Sep 29, 2004
    Actually, it's probably NOT RFI, it's the low-frequency magnetic field produced by the electronics in the CRT.

    If you can't replace the CRT with LCD then the next idea is to orient the mic so that it's null is pointing at the CRT, which will reduce the interference.

    Change the mic! Some mics are less susceptible to this type of pickup than others. I faced this same problem in the studios at the radio station where I work. I ended up replacing the mics (17" LCDs were HUGELY expensive at the time) and, since nobody liked the sound of the mics in the production rooms, I killed two birds with one stone.

    After that, try this: record silence for a minute. Look at the signal's frequency spectrum on a plug-in. My bet is that it will have discrete frequencies. Null them with an EQ (some do harmonic nulling, like power line noise). That should help clean up the mess.

    good luck
  13. Big_D

    Big_D Well-Known Member

    Aug 21, 2004
    Quakertown PA
    Actually it's an EMI issue, electro-mechanical interference. It comes from the interaction of the magnets in the guitar pickup with the magnets that steer the electron beam in the CRT.
  14. imagineaudio

    imagineaudio Active Member

    Nov 24, 2004
    get a mackie control......I hardly ever have my monitors during tracking once a new project is set of the best investments I've made
  15. cajunboy2k71

    cajunboy2k71 Guest

    Check for lcd monitors. They sell them pretty cheap. Sometimes with free shipping.

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