wind interference on tie mics

Discussion in 'Professional Video Production' started by Rayne, Jun 28, 2006.

  1. Rayne

    Rayne Guest

    Hi guys,
    When recording in a high wind environment, is it possible for the wind
    to interfere with the radio signal, eg, reduce range or something that
    might cause dropouts? can wind interfere with radio transmissions?
     
    Rayne, Jun 28, 2006
    #1
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  2. Rayne

    Don Pearce Guest

    Yes, sort of. It has no effect on the signal itself, but it can have
    secondary effects. The most obvious is that it can blow the antennas
    around, and if they are particularly directional, they might lose
    contact. The other is tat the scenery tends to get mobile, and if your
    antennas are non-directional you may find that reflected signals of
    fast-varying phase start to cause problems to reception.

    If what you are talking about is a body-worn mic pack and a receiver a
    few yards away, don't worry - there will be no effect.

    d
     
    Don Pearce, Jun 28, 2006
    #2
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  3. No. It can, however, cause movement of things that will interfere with
    radio transmissions (e.g., antennas, faulty cable, connectors, etc.).
     
    St. John Smythe, Jun 28, 2006
    #3
  4. Rayne

    Scott Dorsey Guest

    No. However, you can get atmospheric interference issues. For example,
    if you're using a wireless that is on TV channel 5, since you're in a city
    without any channel 5, you may occasionally get low-level clouds that duct
    the signal from a station a considerable distance away. I've heard FM
    stations in Florida here in Virginia as a result of ducting.

    Ducting tends to be less of an issue at higher frequencies.. you won't
    see it much at all on UHF, but on VHF-LO (2-6) channels it can be pretty
    bad at times. Takes humid weather, and two layers of clouds to act as
    a waveguide.
    --scott
     
    Scott Dorsey, Jun 28, 2006
    #4
  5. Rayne

    Marc Wielage Guest

    Not in my experience, not unless the transmitting or receiving antennas are
    moving around.

    What frequencies are you using? How much power are you using in the
    transmitter? How far away is the transmitter from the receiver? And what
    kind of equipment are you using? If I knew those answers, I could give you
    some specific information.

    You'd find more answers on the Usenet group rec.arts.movies.production.sound,
    from the guys who use wireless mikes for feature films, TV shows and
    documentaries. You can also get some free information from Lectrosonics'
    website at www.lectrosonics.com. Lectro has a good (and free) 66-page
    booklet on how to set up and use wireless mikes, available here:

    http://www.lectrosonics.com/wg/wg2000.htm

    --MFW
     
    Marc Wielage, Jun 29, 2006
    #5
  6. Rayne

    Phil Allison Guest

    ** Groper alert !!


    ** Yes.

    Wind causes the tie mic capsule to produce large sub sonic signals.

    This in turn causes the limiter and / or range compressor built into the mic
    transmitter and receiver to react and drop the volume level - possibly by
    a large amount.

    Can sound like a drop out.




    ....... Phil
     
    Phil Allison, Jun 29, 2006
    #6
  7. Rayne

    Ty Ford Guest

    Wow! Phil and I agreeing on something! That doesn't happen very often. How
    nice! Can we please keep this up or is it simply a near space anomaly?

    I have had some weird effects caused by subsonic sound as Phil describes. It
    was an outdoors shoot. I could hear the REALLY LOW energy on my MDR7506
    phones as it pushed the limiter. Could have been the wind, although I don't
    recall it being windy that day and we weren't taking typical wind hits. I was
    using a Countryman B6 and a Shure FP410 automixer.

    If you have it again, engage the high pass filter and see it that stops it.
    In a few situations I have experienced a lot of low frequency energy pulling
    down the power supply on battery powered mixers to a point where they get
    wacky, especially if the headphone level is relatively high.

    I had a Sound Devices 302 begin to motorboat when using a AB to Phantom
    barrel adapter with the phone level jacked up. When I switched in the high
    pass filter, the motorboating stopped. The explanation I was given was that
    the low frequencies, barrel adapter and loud phones were pulling more current
    from the power supply than it had to offer.

    Regards,

    Ty Ford



    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at www.tyford.com
     
    Ty Ford, Jun 29, 2006
    #7
  8. Rayne

    Phil Allison Guest

    "Ty Ford"

    ** Houston - we have a problem ........



    ** Right - the issue may be down to the unnecessarily extended LF
    response of the mic capsule itself, rather than any subsequent electronics.


    ** Nobody ever said you could use a tie clip mic in a hurricane ...




    ....... Phil
     
    Phil Allison, Jun 29, 2006
    #8
  9. Rayne

    Marc Wielage Guest

    The Countryman B6's are notoriously sensitive to wind. I think you'd get
    much better performance on windy days with a Tram TR-50, particularly in one
    of their special clips. You might also look into the Rycote windjammers in
    extreme cases. I've used the Sony ECM-77's as well, and those can also sound
    very good in some cases.

    I think the Countryman B6's can be useful, when you need an ultra-tiny
    lavaliere that's impossible to hide otherwise. But it's not a mike I'd ever
    choose for a windy outdoor situation. I agree that low-end rumble can be a
    tough problem to overcome in cases like that. I'd roll everything off below
    100 Hz and see if that helps.

    --MFW
     
    Marc Wielage, Jun 30, 2006
    #9
  10. Rayne

    WillStG Guest

    I have noticed this a _lot_ mixing TV, even coming down the line
    from remotes or on tapes. If you aren't listening loud enough to hear
    the real low end stuff, you might wonder at your limiters going crazy
    for no apparent reason. Whoever is mixing the location shoot *has to*
    engage their filters or every protection device in the tramsmission
    path between them and the studio can react unpredictably, and sometimes
    the limiters will just bury the voice in noise you can't hear!

    Another good one, very similar but different, is that sometimes you
    can get a digital line coming in, that when not properly
    encoded/decoded before it gets to you, can't be recorded or decoded
    past a generation - almost like copy protection, but not. We had some
    Sattelite digital audio from the Olympics that we could hear on the
    digital mixer's 2 buss, but that _would not pass_ through the mix minus
    busses and that the digital tape decks recorded as silence! Fortuntely
    Master Control that day was an analog studio, so it did get passed to
    the net, but the show histories being recorded for updates recorded
    that section of the show as silence. Very weird, we had to convert to
    analog in master and distribute it around the plant analog to work
    around the problem.

    Will Miho
    NY TV/Audio Post/Music/Live Sound Guy
    "The large print giveth and the small print taketh away..." Tom Waits
     
    WillStG, Jun 30, 2006
    #10
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