Room Equalization - Final Results ????

Discussion in 'Archived Threads 2001-2004' started by Kirk Mango, Mar 4, 2003.

  1. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Not to long ago I posted what my room response was at the lower frequencies due to a peak I was having in the 40hz - 50hz range. Wayne helped tremendously as well did others. I have still been playing with it a little and would like to post my original numbers along with the raw data after equalization and with the Rat SChack SPL adjustments and see what everyone thinks?

    I used a the lowest test tone from my B&K Pre amp of 42dB and tested from 20hz - 94hz. The first row of numbers is the HZ, the second is the Db with no adjustments / original system set up, the 3rd set is with adjustments listed at the bottom of the post, and the 4th set is with the spl correction factors added in. Here are the numbers:

    Hz Db Dbw/adj Dbw/corr.
    20626371
    22656976
    24707075
    26707176
    28727276
    30717175
    32707073
    34707073
    36717073
    38727173
    40767375
    42797476
    44797476
    46807476
    48797476
    50767375
    52747273
    54757273
    56747274
    58757274
    60767577
    62767476
    64787677
    66787778
    68767678
    70757677
    72757678
    74757879
    76757879
    78737678
    80707577
    82687476
    84667374
    86647071
    88656769
    90656466
    92636264
    94626162

    The adjustments I made included:
    - setting a -6.5db filter at 46hz with a width of 38hz- 53hz. This I did with my preamp. However, there is only one filter available.

    -setting my center speaker to small (along w/all surrounds)since its rated down to 38hz, used to be set to large. First set of data is with the center set to large)

    - adjustment of my Rel Storm III crossover from 23hz to 25 hz (my mains are set to large in order to take advantage of the high level connection to them from the sub. This allows the sub to support my mains after they roll off. My mains are rated down to 22hz, however, I am sure they start their roll off somwhere in the low 30's)

    My questions are how good is this response? Would this be considered a pretty flat response? How much better can it get? Lastly, if I set the Center speaker to large I will diminish the peak in the 66hz - 82hz range. However, I will then lose the abliity to effectively reporduce hz ranges below 40 which are sent to my center during movies. I can change my crossover, currently at 80hz, however it is global not individual per speaker. Any comments appreciated.

    KM
     
  2. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Wayne? Anybody? How come no responses?

    KM
     
  3. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Just keeping this current for response

    KM
     
  4. Wayne A. Pflughaupt

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    Wayne
    This is only the second time I’ve seen B&K’s built-in filters in action, and I was as impressed with the first as I am with this one. Their accuracy and precision is impressive.

    Your response is amazingly good, Kirk, considering it’s achieved with only one filter, and considering all the low frequency sources you have operating.

    The main problem I see is an inverse house curve. If you can find a way to reduce the 63-80Hz area between 4-6dB, I think you will find things sound much more natural and not as “thick.”

    Regards,
    Wayne A. Pflughaupt
     
  5. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Wayne,

    Thanks for trhe response. If i set my center speaker to large, then the sub will not pick up the extra bass below the crossover of 80hz that my processor is sending it now because the Center is set to small at present. My center is pretty capable, rated down to 38hz. I am sure it rolls -off in the 40's somewhere. However, this would mean I would lose information that is sent to the center and is below say 40hz. Now this may not be a big deal, depends on if the directors automatically send anything below 80 to the sub anywhay. I guess it depends on the director. Here are the spl numbers from 62 - 80hz with the center set to large. This is raw data

    Hz Db
    62 75
    64 76
    66 77
    68 75
    70 75
    72 74
    74 75
    76 74
    78 72
    80 70

    As you can see it isn't a huge difference, but it does decrease the peak a lttle and it does cause a faster taper off from the peak. Must be because of the efficiency of the sub as well as its corner loading. My center is on the TV. Is this the best solution or is their something else I could try witout getting into more expence.

    KM
     
  6. Wayne A. Pflughaupt

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    Kirk,

    Don’t know what else you can try in your situation. Having the sub crossover set so low somewhat limits flexibility (like being able to lower or raise low frequency response at a single source).

    For instance, if your crossover was set around 80-100Hz I'd suggest turning up the bass knob several dB. This would "ramp up" the lowest frequencies beyond the 63-80Hz area. Then the sub's level could be lowered to bring it all back into balance. But this is not an option the way you have things set up.

    If your mains have powered woofers, you might try lowering their level.

     
  7. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Wayne thanks for all your responses. I only use my center for movies, I listen to music only in stereo. My mains have been tuned down already. They have special hz and db knobs on them and they are set to =3db in the 68hz range. This seemed to sound the best. In a movie like matrix with the center set to small, I can hear some lower hz special effects sounds that I do not distiquish when the center is set to large. They are difficult to make out but are present if you listen closely. I think I will leave things as is. If my response is conseidered very good at present then I have achieved my original goal. That was to purchase equipment that would reproduce music and movies as the director intended them to be heard. I do not believe in adding or subtracting any extra information. Thanks for all your responses.

    KM
     

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