Interested in house curve? Read this.

Discussion in 'Archived Threads 2001-2004' started by Troy_K, Mar 14, 2002.

  1. Troy_K

    Troy_K Stunt Coordinator

    Joined:
    Jan 20, 2002
    Messages:
    87
    Likes Received:
    0
    Trophy Points:
    0
    I've been following the house curve discussions, and sort of thought of an easy way to incorporate one. Now, this question requires a "general" answer, and is in no way thought to be looking for scientific fact.

    It seems intuitive that two facts are present:

    1. House curve seems to me to be defined as a gradual 10 db or so decrease in volume fro 20hz to 80ish.

    2. The Rat Shak meter has a built in reading error of approximately this same thing.

    Here's the question: To get a "general" house curve, wouldn't it be easiest to calibrate your sub with an eq/BFD so that it is flattest as possible WITHOUT applying SPL meter correction values?

    Sure this may result in 1-2 db difference at a given frequency from doing it the "pain in the ass" way, but wouldn't one get generally the same result? Just think how much faster the process would be via this method.

    Troy
     
  2. John H

    John H Second Unit

    Joined:
    Nov 27, 1998
    Messages:
    472
    Likes Received:
    0
    Trophy Points:
    0
    Quote taken from this thread on the subject.
     
  3. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Trophy Points:
    0
    Bull's eye!

    Just what I've done!
     
  4. Mark Guidry

    Mark Guidry Stunt Coordinator

    Joined:
    Dec 28, 2001
    Messages:
    222
    Likes Received:
    0
    Trophy Points:
    0
    So do you not apply the correctin values when you use the SPL meter set on C weighting??
     
  5. Rick Radford

    Rick Radford Supporting Actor

    Joined:
    May 12, 2001
    Messages:
    642
    Likes Received:
    0
    Trophy Points:
    0
    >So do you not apply the correctin values when you use the SPL meter set on C weighting??<

    No need to for the initial measurement, Mark (if you want a "house curve"). Use the uncorrected measurement to tweak each filter starting with the lowest freq first.

    When you're done with all filters, take a final reading and then apply the correction. If you sucessfully obtained a flat, uncorrected response curve, you should see a built in 6-8 dB rise as the freqs go lower with the RS corrections applied.

    If you want the response curve flat, then apply the RS corrections to the initial measurement and tweak your filters from that perspective. Then, your final measurement after all filters are set and the RS correction applied should show a flat response curve.

    If you have the BFD1124p (and have the time), you may want to set up one channel with uncorrected filters (ie, built in house curve) and a different channel with corrected filters. Then you can easily switch channels to listen to the difference.
     
  6. Mark Guidry

    Mark Guidry Stunt Coordinator

    Joined:
    Dec 28, 2001
    Messages:
    222
    Likes Received:
    0
    Trophy Points:
    0
    I do not have a EQ or a BFD but I do have some more questions that maybe you can answer HERE
    Thanks
    Mark
     
  7. Wayne A. Pflughaupt

    Moderator

    Joined:
    Aug 5, 1999
    Messages:
    6,207
    Likes Received:
    56
    Trophy Points:
    9,110
    Location:
    Katy, TX
    Real Name:
    Wayne
    Troy,
    I don’t think this is the best way to do a house curve because:
    • It locks you into a pre-determined curve and slope. The amount of actual house curve needed is determined by the size of your room. A large room will need less slope than a small room. There is no adjustment for this by simply going with the built-in slope from the uncorrected RS readings.
    • It locks you into a pre-determined starting point for the slope. The RS meter doesn’t begin to register increased response deviations until 40Hz. Above that deviations are fairly consistent at 1.5-2dB. In my room the curve needed to start much higher, at about 100Hz - although others I have talked to said theirs starts at 50Hz.
    • It continues the slope further than you probably want. I found that the curve needed to level off at about 32Hz or I got a lot of extraneous and unnatural-sounding low freq energy. For instance, when a car door slams you shouldn’t be hearing and feeling it down to 20Hz.
    The best thing I have come up with in determining a house curve is to ditch the meter after setting up fairly flat equalized response, and listen. Play a few random test tones between 100Hz and 32Hz (being careful to avoid known nulls). They should all sound like they are at the same level. If not, you could dial in a narrow filter on a parametric EQ centered at 32Hz and increase gain until 32Hz sounds as loud as 100Hz. Then taking SPL readings at 32Hz and 100Hz can tell how many decibels of slope your room needs.
    At that point you could reintroduce the meter and adjust the equalizer so that the frequencies between those points show a smooth and gradual rise. It is also advisable to use the meter to make sure response is flat below 32Hz, or does not rise as much.
    I expect the best way to determine at what point your rise should begin is once again to listen after you have set up what measures as a smooth curve between 100Hz and 80Hz. You may find that you need to start your slope higher or lower than 100Hz.
    Regards,
    Wayne A. Pflughaupt
     

Share This Page