Haha, look at my bass DBs

Discussion in 'Speakers' started by Jonny K, May 27, 2003.

  1. Jonny K

    Jonny K Second Unit

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    Today I collected some data. I've got an Adire Tempest driver built into an "Adire Alignment" box. It's an awesome sub. To collect some data about it I used a CD I had created with sin waves at HZ levels from 20 up to 160 in 5 HZ increments. I set the amp gain all the way up (AVA250 rated at 270W), the crossover to the middle (maybe 100 HZ?), and the volume at about "26" on my Kenwood 1080VR receiver (0 being the loudest, 99 quietest). I then collected DB readings with my radio shack meter from my standard sitting position. (I mounted the meter on a chair so it wouldn't move).

    Well my results were interesting. [​IMG]

    http://www.telusplanet.net/public/kord/tempest

    Hah. Pretty crappy eh? My guess is that all the junk in this room is absorbing sounds and messing with reflections. For some frequencies, simply moving my head up/down/left/right would make the bass dissapear, or become incredibly strong. It's particularily annoying.

    Unfortunatly, I can't do anything about this. I'm but one of several people living in this home, and my dad is mad enough about the sub as it is - no way I'll be able to renovate the basement to get a better home theater.

    Hah.

    Oh, and by the way. Did I collect data properly? Is there a different method I should use?


    Jonny K. [​IMG]
     
  2. Keith Mickunas

    Keith Mickunas Cinematographer

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    Did you account for the error in the RS meter? Its pretty significant at some of the lower frequencies. I think you'll find some of this is even worse than you think. Do some searching and you should be able to come up with the error values, the spread sheet I've used has them built in, so I don't remember them.
     
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  4. Jonny K

    Jonny K Second Unit

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    Cool, I'll look into it. Problem is, this is one HUGE sub, and very heavy. I can't really put it in many places because the room is very cramped. Hah.


    Jonny K.
     
  5. BrianJ>Y

    BrianJ>Y Stunt Coordinator

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    Try using the phase control. Play around with various levels such as 1/4,1/2,3/4, and 180. I get different frequency responses with each of the above settings and have smoothed out many, but not all of my peaks and nulls.
     
  6. Jonny K

    Jonny K Second Unit

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    Yeah, phase is a tough one to play with though, since it's just me. I'll go up to the sub, turn the knob, go back to where I was sitting, and by that time my ears have adjusted to the bass right next to the sub, so suddenly the bass sounds weak from my sitting position. Either that, or I keep stopping the sound from playing, running back and forth, etc. Not too effective (and I doubt I'll be able to tell the difference in the sound that way).

    I suppose I could run a gamut of tests for multiple phase positions and record my results in DB, but that would certainly take a little while and I'm short on time at the moment.

    Is it "DB" or "dB" or "db" or what?

    Thanks.


    Jonny K.
     
  7. Pedro Diaz

    Pedro Diaz Agent

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    It is "dB".

    "d" comes from "deci". Mmhh, I dont know how to write/say it in english but in spanish it is the tenth part of a whole.

    "B" comes from Bell. Its a family name and it comes from Graham Bell.
     
  8. Jonny K

    Jonny K Second Unit

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    Excellent. dB.

    Thanks.


    Jonny K. [​IMG]
     
  9. Lew Crippen

    Lew Crippen Executive Producer

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