Please help me with my BFD to EQ my SVS 20-39PC+ sub

Discussion in 'Speakers & Subwoofers' started by Jeffrey_B, Dec 8, 2003.

  1. Jeffrey_B

    Jeffrey_B Agent

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    I recently purchased a Behringer Feedback Destroyer (BFD) to EQ my SVS 20-39 PC+ sub (which I have had for over a year now). I thoroughly enjoy the SVS but would like to get the most performance from it that I can. Using my Radio Shack meter and Stryke Bass Zone audio CD, I have found that I have some rough spots in my 20 – 200 Hz low end that needs smoothing out (HOW DO I ATTACH A FILE TO A POST?) . I was considering a graphic EQ such as the ART or Rane that SVS has on their web site, but after some research, I’ve found that the BFD provides a lot of flexibility, and at a great price. I plan on adding a second SVS 20-39 PC+ and it will likely not be co-located with the first one and so the 2 channels that the BFD has an added benefit.

    I want to thank Sonnie Parker for his DUMMIES GUIDE, which helped me get over the BFD intimidation factor (this guide was a key decision maker in deciding to go with the BFD rather than a graphic EQ). Also the info notes from Ken Bruce, and all the useful posts from Wayne Pflughaupt. Finally, the Excel Spreadsheet from Chris Tsutsui makes reviewing my frequency response a snap, and is extremely helpful in targeting the problem areas, and seeing what affect the BFD has when making adjustments.

    The family room, where our home theater is located, is on the first floor of our 2-story house (concrete slab foundation). The family room is about 24 feet wide by 13 feet deep by 8 feet high (about 2500 cubic feet) with wood paneling. The right wall (13 feet) is a brick wall with a fireplace in the middle; all along the wall is a concrete slate ledge extending out about 20 inches and about the same height off the floor. It is in the right FRONT corner that my SVS sub is located (just to the right of my AV rack upon which the right speaker (Polk Lsi9) sits. I may have room to add the second sub here, or at the right REAR corner. I have no other corners to locate these subs. The left wall has doors, at each corner, leading to other rooms. The only opening in the family room is a 3 foot wide stair case leading to the upper floor (its near the left, along the front 22 foot wide wall). So, my sub is NOT on the floor, but rather, about one and a half feet off the floor and sitting on a concrete/slate ledge. I hope this helps with how my set up is oriented.

    I’ve had previously calibrated my sub about 3 db hot relative to my mains (I use AVIA for all my HT calibrations). Using the Stryke BassZone audio CD, I took measurements from 20 Hz to 200 Hz (I would like to attach my results, which has raw and adjusted values). My Sony ES 30 receiver is about 4 years old now (bought it when I first got into HT) and it has a fixed crossover – which is high (about 100 or 120 Hz as far as I can tell). I’ve never found any documentation indicating what the exact x-over is for this receiver (anybody know)? I run my speakers set to SMALL and let the sub handle the low end. This is how my system was set up when I took these measurements.

    So, I hope you can help me out. I’m looking forward to taking advantage of all the expertise here on this forum and to improving my sub’s performance. Thanks to all. The BFD is an inexpensive, versatile, and worthy investment. JEFF
     
  2. Deane Johnson

    Deane Johnson Supporting Actor

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    You're right, the BFD is a great equalizer for the money. I've had mine for several years now and couldn't operate without it. I had a 16 db room spike at 42hz which it tamed nicely.

    Your post above is thorough, but I didn't figure out what your question was as to what you wish help with. Could you be more direct?
     
  3. Paul_Ptaaty

    Paul_Ptaaty Stunt Coordinator

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    So what exactly is your question?

    do you need to know how to use the parametic eq filters on the BFD or are you stuck on the setup?

    Once you know what you want to do (ie remove 6 dB from 45-40 Hz, etc)

    you:

    1. pick a program (1-10 are choices)
    2. pick a filter (1-12 are choices)
    3. choose PA for filter type (parametric)
    4. pick a freq area, (in steps)
    5. use the 1/60 fine to pick the exact freq of the center of the band you want to adjust (see the chart in the manual to help with this and step 4)
    6. pick a "bandwidth" or how much of the freq spectrum you want to affect. This is given by 1/60 steps of an octave (see the same chart you used to pick the freq in the manual to get an idea)
    7. adjust the gain (+/- dB) for that area
    8. now the light on the button on the left should be flashing, double click it to save.
    9. repeat for any remaining areas.

    General setup ideas:
    1. move sub to get one or two bad peaks, trying to minimize valleys, which can't be affected by eq much.
    2. if you want a house curve or other sort of slope, use a large filter outside of the affected range, like 400 Hz, put in a huge cut (30 dB+) and a fairly wide bandwidth. Param eqs make a tapering curve sort of like a distribution curve and will affect areas outside of where you specifically tried to adjust, use it to your advantage.
    3. Use multiple programs, if you copy your flat curve, you can add an extra really broad filter to just change the overall bass level. I use this with DVD-A and SACD since the bass level is low (-10 dB cut) because of how the material is recorded. Now I have an easy fix with no menus, simply change the BFD program and perfect bass.
    4. When you add a filter, the added processing adds a slight delay to the sub channel. Using my Pioneer Elite, it adds about 1.5-2 ft (2 milliseconds) so you will have to adjust for that *edit* the delay seems to be independant of the # of filters, just that if you use any type of eq it goes through an extra processing step which is what adds the delay. If you don't have a time delay setting for your sub channel, and have a variable phase adjustment on your sub, you can try to adjust that as well, I don't know how much it will help however.

    I hope this aids those setting up their BFDs!!
     
  4. Jeffrey_B

    Jeffrey_B Agent

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    Thank you... I'm sorry I wasn't clear (all the excitement). I understand how to use the BFD and have started playing with the filters and seeing what effect they have. However, I'm just poking inthe dark and could use some evaluation of my un-EQ'd freq response curve. I have an Excel spreadsheet that I'd liketo post so I can get some suggestions on BFD settings.

    But I don't know how to attach an file (ie, a GIF) or, embed it in my posts.

    Any help would be appreciated. Then, you'll see my starting point and can help me with where to direct my filters (fre, bandwidth, and gain). JEFF
     
  5. PaulT

    PaulT Supporting Actor

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    Jeffrey
    You can't attach a file to your post. You need to place the file (better is a jpg or gif image of the file) on a web server somewhere (do you have a home page from your ISP?) and post the link to it. It will show up that way.

    For example, in a similar BFD post in DIY section:
    http://www.hometheaterforum.com/htfo...55#post1860855
    the files he posted are on another server here:
    http://www.meettheferrells.com/ron-and/"before_BFD.jpg"

    I have put the actual file name in quotes for the link, otherwise you would see the jpg image just like the original post by Ronnie Ferrell.
     
  6. Wayne A. Pflughaupt

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  7. Jeffrey_B

    Jeffrey_B Agent

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    Thanks Wayne [​IMG]

    Just wanted to give credit where credit is due. This EQ'ing seems more complex that it appears - at least onthe surface.

    I'll restart this post on another forum I participate in as threads there support attachments.

    Thanks again (you wouldn't remember, but over 4 years ago when I first got into HT, you were kind enough to help me with some speaker set up issues-your advice was very helpful). JEFF
     
  8. Wayne A. Pflughaupt

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    Jeffrey,

     
  9. Jeffrey_B

    Jeffrey_B Agent

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    Wayne

    I sent you a PM

    ...and I'll fix my signature.

    Jeff
     

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