BFD setup question

Discussion in 'Archived Threads 2001-2004' started by MikeHalder, Feb 16, 2002.

  1. MikeHalder

    MikeHalder Stunt Coordinator

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    I will be receiving my BFD this week and had a question about how the setup measurements should be taken. The simplified setup information provided on the troy cable site is going to be very helpful, but I want to find out if I need to run the test tones through my STR-DA777ES with base management to properly EQ my subs. The subs crossovers are bypassed, mains/surrounds are crossed over at 50 Hz, center at 70 Hz through the receiver with the subs connected to the sub out (line level). My LFE highcut filter is set at 120 Hz. If the LFE track is providing signal up to 120 w/o passing any signal to the mains, will this not affect the room response for HT since the subs are EQ'd while crossed over with the mains at a lower frequency? Or should I set up the BFD with just the subs running trough base management w/o the mains connected? I hope this makes sense!

    Thanks,

    Mike
     
  2. Rick Radford

    Rick Radford Supporting Actor

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    >set up the BFD with just the subs running trough base management w/o the mains connected?<
    That's the way I did it, Mike. Run in stereo mode.
    You might want to check out this thread to help you set the input level to your BFD.
    Are you using the manual method of data collection?
     
  3. MikeHalder

    MikeHalder Stunt Coordinator

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    I will be using RS SPL meter and an excel worksheet/graph for gathering information.

    Mike
     
  4. brucek

    brucek Second Unit

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    Mike,

    Well ya, you've got a good point, but I agree with Rick. Do your filter setup in stereo mode with the mains turned off.

    The purpose is to equalize the sub, so only have the sub turned on while you're doing it. Yes, the mains may be crossed at 50Hz and the center at 70Hz and the surrounds at 50Hz and the LFE may go to 120Hz, but if you simply choose the mains crossed output and equalize that, you'll still find where all your peaks are anyway. Even when crossed at 50Hz, there is still substantial information being fed to the sub at least an octave higher than this. If there is a room mode at 70Hz you'll still see it and be able to compensate with a filter.

    Take a reading without any BFD filters first and look at your graph. You'll likely find most of your troubles in the < 60Hz area anyway, but if you make the entire response smooth and dropping off up to 160Hz, then you'll have accomplished all you need to do.

    I suppose if you wanted to take the time for interest sake, you could temporarily raise the mains cross to 70Hz and take a set of readings and check the effectiveness of your filters at that cross too. Might be interesting.

    brucek
     

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