Argh..this sub is tooo sensitive!

Discussion in 'Archived Threads 2001-2004' started by tom_furman, Oct 2, 2002.

  1. tom_furman

    tom_furman Stunt Coordinator

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    Helo..me and my buddy just got done making a new Tempest sub. I already have one and he wanted one as well. We hooked it up in his room, and it seems to sensitive. If we watch a dvd, it seems like the sub is almost always rumbling a little. It booms during explosions, but is parts when you dont think the sub should be doing anything it sometimes rumbles just a bit to notice. It can be a bit ditracting. We adjusted the level on the sub amp, but to make any real difference we have to turn the level almost all the way down! what gives?
     
  2. Michael R Price

    Michael R Price Screenwriter

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    Tom, did you calibrate the sub? How is it connected and where in the room did you put it?
     
  3. tom_furman

    tom_furman Stunt Coordinator

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    Well I dont have a sound level meter...BOO to me i know [​IMG] but i do have the avia guide so I have done SOME calibration..even if it was crude. I have it in the corner of the room (only place this beast will really fit!), with a bureau on the other side. There is about 6" clearance from the wall to side of sub, and about 6" from the other side of the sub to the bureau.
    oh..and its just connected from the sub out on his receiver to the plate amp on the sub.
    we just watched the big cannon scene from gettysburg, and we both said that our ears were sore after!!??
     
  4. Greg_R

    Greg_R Screenwriter

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    You need to get a SPL meter... it sounds like your sub level is too hot (vs. proper calibration, not necessarily preference!).

    As for LFE signal, this occurs throughout most movies. My Crown amp has a LED that lights up when a signal is being amplified. Even during some silent sections the LED will glow faintly. If I crank the sub to +10 over reference I hear a constant rumble as well (large explosions can damage your sub at this level if you don't have a limiter).
     
  5. Michael R Price

    Michael R Price Screenwriter

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    I agree, without calibration it's easy to set your sub WAY too loud, especially with a low crossover frequency. The constant rumbles are a sign that you may be hearing the bass part of the movie's background noise amplified much louder than it should be. You say the sub "booms" during explosions... is it distorting at all? (I know, it's hard to distort a Tempest. But if you are, and you aren't insane, you're probably driving it too hard.)
     
  6. tom_furman

    tom_furman Stunt Coordinator

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    Well when i said booms i meant it shakes the entire room. the bass sounds as expected. so if i run out and get an spl meter and i play the test tones on my receiver (or avia). i just hold the spl meter in front of the speaker/sub and try to get them all as close as i can?
     
  7. Arron H

    Arron H Second Unit

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    You'll want to take the measurements from the primary listening position. I'm about 6'5" and so, I end up on my knees with my arm fully extended and pointed toward the center speaker. Putting the meter on a tripod at earlevel from the primary listening position and angled toward your center speaker would be ideal. Try to get all of the speakers to read 85Db if using Avia. The sub reading is about 2-3 Db hot with the RS spl meter and so, if you want the sub set at the same level as the mains, set the sub at 83Db. Use Avia rather than your receiver's tones. Most receiver tones are notoriously bad.
     
  8. tom_furman

    tom_furman Stunt Coordinator

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    is 85Db considered reference level? and thats why i should aim for that level?

    also...to get my sub up/down to that Db level, i should only play with the "level" knob on the plate amp correct? not the crossover or phase.
     
  9. Ben Jordan

    Ben Jordan Stunt Coordinator

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    Also be sure to keep that meter at a 90 degree angle from the speakers. This means it will be pointed up toward the ceiling. (According to what Avia recommends)
     
  10. jeff lam

    jeff lam Screenwriter

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    Tom,
    85dB isn't reference level, but rather a level used to set reference level(Avia uses 85dB, VE uses 75dB, but both set your reference to 105dB peeks). Dolby labs says reference level is peeks at 105dB. Avia's tones are already attenuated 20dB so you can measure the levels without blowing your ears off. So at the volume level you use to get your speakers set to 85dB with Avia. Playback a DVD at that same volume level will give you 105dB peeks. The only reason they use 85dB tones instead of 105dB tones is because 105dB tones would be unbearable to listen to.
     
  11. Dustin B

    Dustin B Producer

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    Also reference level is very loud. And most systems can't do reference level cleanly. I generally watch movies at 10dB below reference with the sub slightly hot.
     
  12. tom_furman

    tom_furman Stunt Coordinator

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    ooo..i cant wait for a spl meter. i'm dying to know what Db level i usually watch movies at! so that's the gain knob...

    i already aksed you guys about the phase knob...

    now is there a way to calibrate where the crossover should be, or is that more of a personal preference thing?
     
  13. Dustin B

    Dustin B Producer

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    Unless you are running the sub as no on your processor and are using the plate amp as the crossover (which you shouldn't be doing unless you have a plate amp like the HS series from Adire and are looping line level main connections through it and out to a seperate amp) the crossover dial should be set as high as it will go so that it won't affect what is being done by your processor.
     
  14. tom_furman

    tom_furman Stunt Coordinator

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    Ah-ha..I have the sub on YES on my receiver and am using a plain old PE 25w amp so I guess I better go turn the crossover up!
     
  15. Dustin B

    Dustin B Producer

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    Make sure all other speakers are set to small as well.
     
  16. Arron H

    Arron H Second Unit

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