Do I need a BFD based on this graph?

Discussion in 'Archived Threads 2001-2004' started by Jeffrey_S, May 7, 2002.

  1. Jeffrey_S

    Jeffrey_S Stunt Coordinator

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    Hi,
    I finished my DIY Adire Alignment vented Tempest sub a couple of weeks ago and thought I'd plot out my room response to it using a Radio Shack meter (with adjusted values) and some sine wave frequencies. What do you all think? I know I have some minor peaks and a general downward trend to the graph, but isn't this in line with a "house curve"? Would I benefit from a BFD?
    [​IMG]
    Any input would be appreciated.
    Thanks,
    Jeff
     
  2. Michael R Price

    Michael R Price Screenwriter

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    Wow that's an amazing room response, +/-3dB 16-70Hz...you don't need a BFD but there's never anything wrong with adding another toy to your rack. Where did you put the sub and how big is your room?

    BTW, how do you like the Tempest? A friend of mine just built the same alignment. The general conclusion is that it "kicks ass."
     
  3. Jeffrey_S

    Jeffrey_S Stunt Coordinator

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    Michael,
    My basic layout is shown below:
    [​IMG]
    I've had the sub up and running for about 2 weeks and I'm really impressed. Here is a thread I started showing the sub:
    http://www.hometheaterforum.com/htfo...threadid=68136
    I agree about the toy thing. But I was really suprised that my graph looked so good (at least to my inexperienced eyes).
    Jeff
     
  4. brucek

    brucek Second Unit

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  5. Chris PC

    Chris PC Producer

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    I'd have to say NO also. After seeing a really good graph in terms of flatness, I have to ask; How does it sound to you for music and movies?
     
  6. Jeffrey_S

    Jeffrey_S Stunt Coordinator

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    Chris,

    Actually, it sounds pretty good! The dip at 45Hz is where my recessed light fixtures vibrate and this is probably my biggest complaint about the sound of my hometheater. Other than that I'm pretty satisfied and only did this graphing as an exercise.

    Thanks to all who responded.

    Jeff
     
  7. Scott Simonian

    Scott Simonian Screenwriter

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    [​IMG]
    OMG! That is a wonderful room response. Mine looks like the Rocky Mountains in comparison.
     
  8. Wayne A. Pflughaupt

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    That is indeed amazing equalized response. The BFD could help you with a house curve, if you think you need one.

    Regards,

    Wayne A. Pflughaupt
     
  9. Chris PC

    Chris PC Producer

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    How many frequencies did you measure and how did you measure them anyways? What did you use to make that graph?
     
  10. Michael R Price

    Michael R Price Screenwriter

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    Can you take some of my room variations away from me? I'm +10/-15 dB...

    Wait, isn't that an UNequalized response there?
     
  11. Jeffrey_S

    Jeffrey_S Stunt Coordinator

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    Chris,

    I used Sonnie Parker's mp3 files and the spreadsheet linked to his excellent BFD site. Using my laptop computer, I outputted the mp3 sine wave files directly to my sub. There were 21 frequencies in all: 16Hz, 18Hz, 20Hz, 22Hz, 25Hz, 28Hz, 31.5Hz, 36Hz, 40Hz, 45Hz, 50Hz, 56Hz, 63Hz, 71Hz, 80Hz, 89Hz, 100Hz, 111Hz, 125Hz, 142.5Hz, and 160Hz.

    Jeff
     
  12. Chris PC

    Chris PC Producer

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    Fair enough. If I were you I would put further tweaking and EQ'ing on the backburner. I wouldn't buy an EQ until I did more testing. Since your response is fairly flat testing with the frequencies you used, it couldn't hurt to increase the resolution just to fill in the unknown gaps. Get a program like Sonic Foundry - Sound Force 5 and make test tones from 16 hz to 110 hz at 1 hz intervals and put those on a CD. Take your time and then plot a graph using those 1hz intervals. Maybe you'll find a few peaks and dips not evident with your other testing, or maybe you'll simply re-assure yourself how flat your response already is. Either way, it wouldn't hurt. Not really necessary, but since you are already ahead of the game, it can only improve your picture of room response.
     

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