Optimizing Bass Response with an EQ: BFD!!

Discussion in 'Archived Threads 2001-2004' started by Kevin C Brown, Nov 17, 2001.

  1. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Hee, hee. *With* a Behringer BFD...
    I'll try to figure out how to get a graph in here later.
    But, I'm only going after the peaks so far. Largest was centered at 65 Hz, +/- 5 Hz.
    "Filtered" 4 peaks so far. It's late so I decide to quit for the night and pop in a CD.
    Amazing. I can play it "louder" without tripping the SAF (spouse acceptance factor), but it sounds so much better. Less boomy. More definition in the midrange. I know, I know... The highest peak I've dropped is only at 75 Hz, but it just "opens" up the sound. (I crossover everywhere at 80 Hz.)
    This is probably the largest improvement in sound quality I've gotten so far in my system lately, rivalled by moving my speakers out from the front wall (quite a while ago).
    I have to play with it a little more, but an essential piece of gear, in my opinion...
    [​IMG]
    ------------------
     
  2. Chris PC

    Chris PC Producer

    Joined:
    May 12, 2001
    Messages:
    3,975
    Likes Received:
    1
    How much do these BFD's cost and where can they be found?
     
  3. Steve Morgan

    Steve Morgan Second Unit

    Joined:
    Nov 10, 1999
    Messages:
    327
    Likes Received:
    0
    Location:
    Farm in Kansas
    Real Name:
    Steve
    Kevin, can you give me a play by play of how you get to your frequency and cut or boost and set bandwidth. Like the buttons you push and in what order.How do you couple the channels. I could use the help. I am hooking mine up this afternoon.BTW this is Steve the guy that tipped you to where to find your BFD.I think my learning curve on the BFD is very slow.Also do you have dual or a single sub? How did you connect the BFD? Did you get the RS adapters?
    Thanks Steve
    ------------------
     
  4. Brian Bunge

    Brian Bunge Producer

    Joined:
    Sep 11, 2000
    Messages:
    3,716
    Likes Received:
    0
    Chris,
    Check out www.musiciansfriend.com. They have them on sale right now for $129 + shipping. That's a pretty good price so I ordered one myself the other day. Just do a search on "Feedback Destroyer" to find it.
    Brian
    ------------------
     
  5. jeff peterson

    jeff peterson Supporting Actor

    Joined:
    Nov 29, 1998
    Messages:
    675
    Likes Received:
    0
    Brian, that is a good price. I went to order one there myself and then noticed that it's not available until 2/1/2002 [​IMG]
    Guess it'll have to be a pre-order
     
  6. Steve Morgan

    Steve Morgan Second Unit

    Joined:
    Nov 10, 1999
    Messages:
    327
    Likes Received:
    0
    Location:
    Farm in Kansas
    Real Name:
    Steve
    Bump to the top.
    ------------------
     
  7. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Hey is something going on with the new software? I posted a reply to this this morning, big long one too, and it ain't here! [​IMG]
    Steve, let me get home, and I'll do a play by play for you there.
    More general questions though:
    1) If I equalize to a "flat" response at my sitting position, will this screw up response elsewhere in the room?
    2) Should I be optimizing for flat *sub* response, or flat "composite" (sub + mains) response? I have flattened my sub from +/- 7.25 dB to +/- 5 dB. But when I add the mains, some of the peaks "reappear". If I actually dip the sub's response (where it overlaps) I can compensate for the mains peaks to some degree, but should I be doing that?
    (Or maybe I forgot to "post" my preview? ...)
     
  8. Brian Bunge

    Brian Bunge Producer

    Joined:
    Sep 11, 2000
    Messages:
    3,716
    Likes Received:
    0
    Jeff,

    I'll have to check on that availability date. I didn't notice it until after I'd ordered mine. I hope that this will be for the new 1124p that's due out soon. If it's not, I may cancel my order as another place is offering the new one for the same price.

    Brian
     
  9. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Here is a link to a site that actually has the new 1124p. For only $129 too! Has 24 bit internal processing, unlike the 1100p, which has 20 bit processing (but 24 bit DACs and ADCs).
    http://www.lentine.com/pa/equbeh.stm
    But if I attempt to know anything about digital audio and fidelity, 20 to 24 bits for subwoofer range frequency isn't going to get you any improvement in performance.
    With that being said, I *will* probably switch to the 1124p after a few months (and any hardware/software bugs have been worked out). You know, gots to have the latest and the greatest... [​IMG]
    Plus one big downside of the 1100p, is the turn on "thump". Maybe/hopefully, the 1124p won't have it.
    Here is a very useful HTF thread. BruceK's review is very useful. He also references a hometheatertalk FAQ on the BFD, which quite frankly, isn't as useful as his review! [​IMG]
    http://www.hometheaterforum.com/htfo...ight=behringer
    Quick and dirty instructions on how to use an 1100p (and maybe even the 1124p):
    1) Turn the device on. The current program number will be in the display.
    1b) To completely reset all the settings (I did this, because I got mine used): depress Filter Select and Store at the same as turning the unit on.
    2) Choose the program you want to modify. (Spin the knob to change any number setting.) (I used 10 because that is a default "free" program for stereo equalization. Although I am using it in mono mode any way. Right channel.)
    3) 1st thing I did was delete all the filters.
    3a) You have to do this one channel (or "engine") at a time. Press the appropriate engine key.
    3b) Now hit the Filter Select key. There are 12 filters per channel. The 24 filters of both channels comprise the Program. Use the knob to dial in the filter you want to delete.
    3c) Now press filter mode. Use the knob to switch to OF. The Store light will blink. Press it once, the unit "asks" if you want to store the modified "Program" as the same number. Hit Store again if so.
    3d) Repeat 3a through 3c for all 12 filters of each L and R channel.
    4) Now comes the hard part. You have to plot your sub's output vs freq response in your room. I used the Autosounds 2000 CD with the Radio Shack SPL. This plot will tell you where the peaks and valleys are. I recommend that you do the sub 1st by itself. (I just turned off the amp powering my mains.) I have gotten a "pass" (20 to 98 Hz) down to 10 minutes.
    5) Identify where the peaks and valleys are. According to other threads, "flattening" peaks is much more effective than trying to boosts valleys.
    6) Dial in a filter for that peak. Here's and example: I have a peak centered at 65 Hz, about +/- 5 Hz wide. I want to mash it by 5 dB.
    6a) I have my sub cable through the right channel (no reason). With the knob, choose the program (10, for me).
    6b) Choose the filter by using the Filter Select key, then turning the knob to the appropriate filter. Filter 1 for me.
    6c) Now switch the filter to Parametric EQ mode. Hit Filter Mode, and use the knob to get to PA. Now, you will see the Store button light. (Here, I don't know if you have to Store after each and every change, but I did it anyway.) Same-o as before: hit store twice.
    6d) Hit Filter Select again, 1 will come up. Now hit the Frequency key, and I dial down to 63 Hz (the closest value to 65). I Store again.
    6e) Same: hit Filter Select, 1 comes up, then I hit Frequency, 63 comes up, then I hit Fine (1/60). Now, look at the table on pg 28. +2/60 gets me from 63 to 65Hz. So I dial that in and Store (twice) again.
    6f) Filter Select (1). Hit Bandwidth. For me, I want to zap from 60 to 70 Hz. So, looking at the table, from 65 to 70 Hz is +2/60 to +8/60, the delta is 6/60. The bandwidth is +/- so the total is 12/60. So I dial down to 12 (x 1/60). Store twice.
    6g) Filter Select (to 1). Hit gain. Dial in -5dB. Store twice. Bam, that filter is complete.
    6h) Repeat for any other filters. Basically, you just follow the order on pg 10.
    A lit filter means that it is set. Blinking means that it is looking for an auto lock. Unlit means that it is Off.
    The in/out button lit, means that the program is engaged (this is a typo in the manual). Unlit means that the program is bypassed.
    I think that covers most of it! One you do a filter or two, the controls actually do make a little bit more sense.
    And then, I replot to make sure I get an effect. Make sure to use the "correction" for C weighting.
    Here's a neat example for mine.
    Hz pre post dB
    21 75.0 75.0
    22 77.0 75.5
    23 76.0 75.0
    25 78.0 76.0
    26 78.7 75.7
    27 78.4 75.9
    28 77.1 75.1
    29 77.3 75.3
    One cool thing, I have appreciable output down to 21 Hz (Vandersteen V2W baby!)! Drops like a rock at 20 Hz, and I have nothing at 19 Hz.
    But see how the range improved from 3.7 to 1 dB? This is using a filter at 26 Hz, +/- 2 Hz, and -2 dB gain. Very cool. Very powerful.
    I am still playing. But see me grinning? [​IMG]
     

Share This Page