Achieving Flat Bass Response

Discussion in 'Speakers' started by Chris Huber, Aug 19, 2005.

  1. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
    Hey guys, I want to start tackling this issue with my HT. Basically I have a crazy basement room (7k cu ft) with cement floors/walls and lots of corners/angles of walls.

    I also just picked up a SVS 20-39 PC+. Sub sounds really good, but there are some crazy peaks at times.

    Would something like this help me out?
    http://www.snapbug.ws/bfd

    I really didn't want to get into building bass traps and such. They are to much $$$...

    How can I get started?

    I've also got a laptop with MIC in capabilities if that helps...

    I can get you some room pics if that would help out, let me know...
     
  2. Brian L

    Brian L Cinematographer

    Joined:
    Jul 8, 1998
    Messages:
    2,891
    Likes Received:
    4
    Snapbug is a great place to go for help with setting up a Behringer Feedback Destroyer, and it is designed around the Radio Shack SPL meter. If you search the HTF for "BFD", there are lots of threads where it is discussed.

    Another option I can recommend is here:

    http://homepage.ntlworld.com/john.mulcahy/roomeq/

    This program also uses the RS SPL meter, but it actually will compute the settings for the BFD. It requires a bit more effort to set-up, but once its running, it automates the process of setting the BFD.

    Brian
     
  3. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
    How does the BFD hook up to your HT? Is it through the LFE line out->BFD->sub?

    Also, do I need a good quality MIC for my laptop for RoomEQ to work correctly?
     
  4. John Garcia

    John Garcia Executive Producer

    Joined:
    Jun 24, 1999
    Messages:
    11,571
    Likes Received:
    24
    Location:
    NorCal
    Real Name:
    John
    From the link you provided:

     
  5. Wayne Ernst

    Wayne Ernst Cinematographer

    Joined:
    Feb 24, 2002
    Messages:
    2,588
    Likes Received:
    0

    Yes, that is correct.

    I thought the current model of BFD from Behringer was going to become extinct about 6 months back? Surprisingly, I picked one up yesterday at my local Guitar Center for $99 + tax. The salesperson said the BFDs were still in their system and have shown no sign of disappearing anytime soon.
     
  6. Brian L

    Brian L Cinematographer

    Joined:
    Jul 8, 1998
    Messages:
    2,891
    Likes Received:
    4
    RoomEQ was designed to work with the RS SPL Meter. It has built in corrections to offset the "C" Weighting of the meter. It can also work with a higher quality mic, but the author has said that good results can be had with the venerable RS meter.

    I use my BFD only on the sub, so the Sub/LFE output of my AVR goes first to the BFD, then to the sub itself.

    Brian

    PS: OT note to John. Still Karting? I recently got to do some Karting in Brazil. What a blast. Took pole in my session, then fell asleep at the starting line; ended up 4th! Great fun...if only we had a track in my city.
     
  7. John Garcia

    John Garcia Executive Producer

    Joined:
    Jun 24, 1999
    Messages:
    11,571
    Likes Received:
    24
    Location:
    NorCal
    Real Name:
    John
    OT: Brian - Not lately, Speedring lost their lease and went out of business just a few moths ago. There were two others started up in our area though, one by some of the Speedring people, but I haven't had a chance to get over there yet.
     
  8. Kevin_Wadsworth

    Joined:
    May 1, 2003
    Messages:
    39
    Likes Received:
    0
    The av123 R-DES system found here (http://www.av123.com/products_produc...s&product=31.1) would also help you out. Compared to the BFD, it only has 4-bands for equalization, compared to 12. But it does have a much nicer interface and allows you to store up to 5 curves if you like to use different bass response curves for different situations (movies vs. music). Like the BFD, it is designed to work with the Rat Shack SPL meter.

    I have a BFD and it does the job for me. Personally, the nicer interface and stored curves on the BFD wouldn’t be worth the extra money to me, but YMMV.
     
  9. John S

    John S Producer

    Joined:
    Nov 4, 2003
    Messages:
    5,460
    Likes Received:
    0
    Ouch on the price of these things....

    I am glad Velodyne has seen fit to offer EQ in the DLS line, really makes that 15" even more of a bargain.
     
  10. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
    Where can I get the correction/conversion chart in 1hz increments?

    Also, I do have a laptop, but it has no MIDI input (RoomEQ says)... It does have a MIC input though... What can I accomplish with this? Nothing?

    Man, I am just not understanding this stuff yet...

    1. I have the RS meter with the test cd burned from basstraps.com
    2. I need to play the tone cd and record what I get, convert the measurements to real readings.
    3. write each 1hz measurement onto a TXT file.
    4. Import the TXT file into RoomEQ

    Then what? Is this right so far?

    ALso, when playing tones, I get a little pop from the center or front speakers at all vol levels. Whats up withy that? Isn't the sub the only thing that should be audible?
     
  11. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    What's a DLS 15 costs?
     
  12. Wayne Ernst

    Wayne Ernst Cinematographer

    Joined:
    Feb 24, 2002
    Messages:
    2,588
    Likes Received:
    0

    If you're referring to the DD-15 with the digital EQ, the
    MSRP is $4,000.

    [Edit]: I'm quite sure John was being sarchastic regarding the fact that Velodyne was able to throw in the EQ with these subs - and for their price. [​IMG]
     
  13. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Yep that's what I thought.
     
  14. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
    Here is my freq response measurements that I've taken. I used the ACS spreadsheet to complete it. Before I started, I played White Noise on all front channels so that it said 75 on the RS meter. Then, went through and plays the right freq and marked it down.

    Was this the correct way to accomplish this?

    Also, here is the graph.(blue line is 20-39PC+) Let me know what you think or suggest.

    [​IMG]
     
  15. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Did you use the RS meter correction table to compensate?
    If yes other then the slight hump at 16hz, looks pretty amazingly flat to me.
     
  16. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
  17. John S

    John S Producer

    Joined:
    Nov 4, 2003
    Messages:
    5,460
    Likes Received:
    0
    No, I am talking about the DLS5000R for around $600. You don't get room eq, but it has eq that helps the extension quite a bit.

    I am attempting to figure out right now, if a custom eq could be burned into the instruction chip though, it seems a possibility.
     
  18. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,043
    Likes Received:
    17
    Location:
    Katy, TX
    Real Name:
    Wayne
    Then the BFD is what you want. [​IMG]

    Regards,
    Wayne A. Pflughaupt
     
  19. Chris Huber

    Chris Huber Second Unit

    Joined:
    Jan 2, 2003
    Messages:
    416
    Likes Received:
    0
    Yes, my current measurements are the blue line. Thats what I said before. The excel had to graphs, so I just made the red line 75 all accross the board.

    So, I do have peaks, correct? If so, the BFD can tame them pretty well?
     
  20. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Yes, for both. I did get confused with the magenta line like Wayne said it.
     

Share This Page