TV flickers when bass hits...

Discussion in 'Archived Threads 2001-2004' started by Pat K, Mar 19, 2002.

  1. Pat K

    Pat K Stunt Coordinator

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    Whenever the bass hits hard on my system, the tv flickers, from darker to lighter. Whats up??
     
  2. Wayne A. Pflughaupt

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    Sounds like the circuit is overloaded, Pat – operating at near maximum and causing voltage sags. Try plugging the sub into a different circuit, or have a dedicated circuit or two installed for your system.

    Regards,

    Wayne A. Pflughaupt
     
  3. Chris Rein

    Chris Rein Stunt Coordinator

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    Ah the hell with the technical answers.....
    What sub are you using that's making your TV freak out?
    [​IMG]
    That's what we all REALLY want to know!
     
  4. Pat K

    Pat K Stunt Coordinator

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    Its an MTX Sub1. 100w, 10", nothing big, sounds pretty good though, especially considering MTX isn't a big name in home theater. Makes my rear walls rattle alot, hopefully when I get my rear surrounds, the sound will cover up the rattle. Im thinking it might be the circuit breaker, cuz my clothes dryer is on there too, and that may have been running when it was flickering, and dryers probably pull alot of power.
     
  5. ColinM

    ColinM Cinematographer

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    Electric dryers are 220v, right? Can that be on the same circuit?

    I am NOT an electrician.....

    But the title of this thread caught my attention, because I've been noticing that I get a horizontal wave-like shimmer on screen whenever I listen at ref (sub +2db).

    Like in TPM, chapter 20, when they are warming up the pods right before the race...there's some good bass there and every time someone gooses the gas pedal on those damm pods, the screen shimmers. It's as if the TV is sitting in a peak area for bass, and the sound waves at low frequencies are causing the wave-like shimmer. Like an oscilloscope or something...It doesn't look like a voltage drop, and there are no signs of power drain when looking at anything else in the room on that circuit (1 lamp, 60w bulb).

    Perhaps I should get a line voltage meter, like that groovy Furman job with the pull-out lights and LED's or somethng...

    - C
     
  6. SanfordL

    SanfordL Stunt Coordinator

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    Hey, a quick way to check if it's the circuit overloaded is one of the following 2:

    1. Turn your system on at the level where you notice TV issues. Wait about 5 minutes, and go to your circuit box. If the circuit is close to the overload, the circuit should be warm. If that's the case, you need to upgrade. Also, if your conduit is such that you can get to it, feel if it is warm.

    2. Ditto for #1 except plug in a hair dryer into the circuit with your system turned up. If you turn it on, and your breaker breaks, you are too close for comfort.

    Next, there is no way in this world that an electric or gas dryer is on a 15 amp circuit unless your electrician should be hung up by his thumbs to rot in the sun. I doubt you can run a 240 off 15 amps, but then again, I'm not an electrician either. Code is 30 amps dedicated solely for the dryer.

    One thing to note, I had to eat buying a new TV about 2 months ago because of the same issue so be warned. Our house had my sons room, our Living Room, the hall, our office, the outside outlets, and our 3/4 HP sump pump on the same 15 amp circuit. So yes, there are scary things to be found in most houses if you look, and some of them can get EXPENSIVE.
     
  7. ColinM

    ColinM Cinematographer

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    I just wonder if bass can distort a picture purely by SPL.

    I would say yes...

    That is my observation, not scientific.

    I am thinking of a dedicated circuit just for the hell of it, electrician in the family and all...
     
  8. ThomasL

    ThomasL Supporting Actor

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    Pat, assuming it's not a power spike, you could also try moving the tv if its not too much trouble. Keep it on the same circuit but move it to see if it is somehow related to SPL levels. You could also try moving the sub to change a possible bass hotspot near your tv. One thing that could be causing it is a vibration issue from the sound waves. Perhaps something is resonating inside the tv causing the image to be affected.

    The dryer should be on a dedicated circuit. If your circuit is spiking oh so briefly, you should see the lights flicker as well if there are any on the same circuit.

    good luck,

    --tom
     
  9. John Garcia

    John Garcia Executive Producer

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    Does it do it with all sources, including music with the TV on?
     
  10. ColinM

    ColinM Cinematographer

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    Who, Me?

    No, only with deep loud effect-type bass, subsonic and +90db.

    Direct view Sony.

    No biggie since I don't see it with normal levels, but for the extreme bass scenes at ref it wiggles the middle third of the image pretty good.

    - C
     
  11. jeff lam

    jeff lam Screenwriter

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    Your vision can get blurry with high enough SPL's. I used to see things shake in my car when the bass hit loud and hard. I thought everything outside was shaking till I realized it was really me and my eyes that were shaking.

    Were talking about 130dB though, so that's LOUD!
     
  12. Pat K

    Pat K Stunt Coordinator

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    130db in car audio isnt really that much. I think the record, for an on the dash mic is around 174 decibels. I know a guy that has two Atomic Thunder 15", and hit a 172. You can't be in the car while this is going on, or you would not only go deaf, but youd probably die. They sometimes have little pods outside the car that the faceplate, or sometimes the entire receiver, is connected to..
     
  13. jeff lam

    jeff lam Screenwriter

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    Pat,

    I know 130dB in car isn't a lot for the competition guys. I'm talking single 12" under 300W. I can probably hit 140-150dB with some distortion in a sealed enclosure at the proper frequency(never tried it and don't have the measuring equipment). I just mean't that vision gets blurry around 120-130dB, that's all. I can't even imagine 170+ dB. Yah, you better not be in the car or you probably will jump start your heart and go into cardiac arrest(Seriously, NO-JOKE!!!).
     
  14. Adam Krogul

    Adam Krogul Stunt Coordinator

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    hey jeff have you ever gone to those new wendy's drive up windows where they have your order on an red lcd screen? Thats when you really notice that your eyes are shaking. but anyway i went to this car show last year and this caviler had 16 10's (i think). he was opening his door for more bass intead of windows. i stood about 10 feet in front of the car and my shirt was moving to the music. needless to say he walked home with the trophy.
     
  15. Heath_R

    Heath_R Stunt Coordinator

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    I guess we have gone off topic here, but I have noticed vision problems with loud car audio. My 2 Kicker SoloBaric 12's hit 148.9DB in USAC Outlaw 0-100.
     

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