BFD setup and my SPL numbers!

Discussion in 'Archived Threads 2001-2004' started by James Elvick, Jan 27, 2002.

  1. James Elvick

    James Elvick Supporting Actor

    Joined:
    Jan 12, 1999
    Messages:
    690
    Likes Received:
    0
    Trophy Points:
    0
    Hello All:

    I finally broke down and bought the Stryke CD and now have done a Radio Shack SPL reading. The sub is a SVS 20-39cs in the front right corner. Here are the RS corrected numbers without any EQ:

    HZ DB

    17.5 82.0

    20.0 84.5

    22.0 84.0

    25.0 85.0

    28.0 77.0

    32.0 84.0

    36.0 73.0

    40.0 79.5

    45.0 87.0

    50.0 94.0

    56.0 84.0

    63.0 82.0

    71.0 86.0

    80.0 75.0

    What filters (including bandwidth and fine) would you suggest as a starting point? Please be specific and I'll try to keep up! Thanks in advance for any and all help!

    James Elvick
     
  2. James Elvick

    James Elvick Supporting Actor

    Joined:
    Jan 12, 1999
    Messages:
    690
    Likes Received:
    0
    Trophy Points:
    0
    OK guys, 40 views and 0 comments?[​IMG] Surely there are some BFD experts out in HTF land that can help a greenpea:b
    Thanks
    James Elvick
    [email protected]
     
  3. Patrick Sun

    Patrick Sun Moderator
    Moderator

    Joined:
    Jun 30, 1999
    Messages:
    38,749
    Likes Received:
    480
    Trophy Points:
    9,110
    Start at taming that peak around 50Hz with a spread of 1/6 (10/60) for the Q. You may find that you have to center the 50Hz around something higher, like 54Hz (I think I had to do this to get the change I wanted). Anyhow, just play around, and make small changes and see what the response does.
     
  4. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    James,

    These are surprisingly poor readings for corner placement. If you plot this on a chart, you can see that response dramatically rips up and down.

    For instance, from the 50Hz peak, response plunges -21dB to 36Hz, soars +11dB at 32Hz, plunges -7dB at 28Hz and soars again +8dB at 25Hz. Four peaks and and three holes over 1-½ octave - way too much.

    Does this corner have openings nearby, like a hallway? If so, try to find a corner with maximum uninterrupted wall length in each direction.

    Also, do you have large main speakers set to “Large?” If so, their low frequency output will interact with the sub and cause cancellation. It would be better to set the speakers to “Small” and let the sub do the low-freq work.

    Regards,

    Wayne A. Pflughaupt
     
  5. James Elvick

    James Elvick Supporting Actor

    Joined:
    Jan 12, 1999
    Messages:
    690
    Likes Received:
    0
    Trophy Points:
    0
    Hello Again,

    I decide to check the only other available corner in my room which was the rear left(thanks Wayne for the suggestion). Speakers are all set to small and this is Sub only, no speakers during test. MUCH better uneq'd results and check these eq'd results:

    FREQ/---RAW SPL/SPL(comp)/-----BFD SPL/ BFD SPL (comp)

    16hz/---68/79.5/ ----- 66/77.5

    18hz/---72/80.0/ ----- 69/77.0

    20hz/---73/80.5/ ----- 68/75.5

    22hz/---80/86.5/ ----- 72/78.5

    25hz/---84/89.0/ ----- 71/76.0

    28hz/---87/91.0/ ----- 71/75.0

    32hz/---91/94.0/ ----- 73/76.0

    36hz/---89/91.5/ ----- 70/72.5

    40hz/---88/90.5/ ----- 71/73.5

    45hz/---93/95.0/ ----- 74/76.0

    50hz/---89/90.5/ ----- 75/76.5

    56hz/---72/73.5/ ----- 66/67.5

    63hz/---80/81.5/ ----- 74/75.5

    71hz/---83/84.5/ ----- 75/76.5

    80hz/---7677.5/ ----- 70/71.5

    Now, I have another 20-39cs coming and can't fit it in the same location. The BFD and Samson both have a extra channel and I will of course EQ seperately if I'm willing to do the work! I assume I'd EQ that additional sub and then check for cancellations and try to get them both to work together? More trouble than its worth?
     
  6. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
     
  7. James Elvick

    James Elvick Supporting Actor

    Joined:
    Jan 12, 1999
    Messages:
    690
    Likes Received:
    0
    Trophy Points:
    0
    Hi Wayne,
    The only problem with stacking is these are SVS 20-39CS and they would be a shallow 80"[​IMG] Putting them right along side of each other may be a possibility if I do some rearranging but it would be pretty tight. Are opposite corners better/worse than corners of the same wall?
    James
     
  8. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
     
  9. Harold Leroy

    Harold Leroy Stunt Coordinator

    Joined:
    Dec 29, 2001
    Messages:
    51
    Likes Received:
    0
    Trophy Points:
    0
    I have a BFD 1124 on it's way--what type cable do I need between my receiver and the BFD...a regular interconnect with RCA coonectors??
     
  10. Rick Radford

    Rick Radford Supporting Actor

    Joined:
    May 12, 2001
    Messages:
    642
    Likes Received:
    0
    Trophy Points:
    0

Share This Page