Bought my BFD and I Have Questions

Discussion in 'Archived Threads 2001-2004' started by Bob U, Mar 3, 2002.

  1. Bob U

    Bob U Stunt Coordinator

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    Hi there,
    Finally bought my BFD and have not yet set it in the rack. Seems it was demo'd, so first thing I did was a factory reset. I read in Sonnie's setup guide that in bypass, the two green dashes "flash". Mine do not. The In/Out button does flash.Is this correct? If not, I will exchange it before I rack it, so this is question one.
    Two, I am scanning the docs I have read online and I tend to remember that someone said to first set all 10 programs to either OF for off or PA for Parametric. Can't remember which and can't find it at the moment.
    Then I am going to test the turn on transient with my subs to see how bad it is. I measured about a volt DC on turn on with a cheap meter. I'll see if its a problem and post here.
    Next, here is an updated curve of my subs with no EQ. I learned that my DVD player with a Stryke CD has a very different bottom end than my CD player. So this curve is from the DVD and Stryke.
    I am going to try to get as close to flat as I can at about 80dB. I have included 400Hz and 1KHz for refernce to see where the mains levels are and to match the end result sub response level with the mains. Thought this would be helpful information.
    On the bottom, between 20 and 36 Hz, I was thinking using 3 filters: 1 at 21Hz to drop that little bump around 3 dB, then one at 31Hz to drop that bump 3 or 4 dB, then one broad filter at 27 to drop the resulting 20-36 "shelf" down to 80 dB. Does this sound like a good approach? Would you suggest something different before I try this?
    Appreciate your comments.
    -=Bob=-
    [​IMG]
     
  2. Matt Barrett

    Matt Barrett Extra

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    Bob,

    The LED on the in/out button will flash when you press and hold it momentarily, this indicates full bypass mode. The two dashes in the digits display will not flash.

    As far as setting all filters in all programs to OFF, I think it is unnecessary but you can do it if you wish. Program 4 is already set to all PA (parametric) filters, so most people just use program 4 to start. It is a good idea to shut off any unused filters in that particular bank though.

    Your idea of using 3 filters to take out the large bump from 20 to 36Hz is exactly what I did to take out a large bump in my system and it worked out well, the best thing to do is try it and see, you can’t beat experimentation!

    Good luck!
     
  3. Bob U

    Bob U Stunt Coordinator

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    Thanks, Matt. Appreciate your reply.

    Do you have your graphs and settings online? I'd be interested in seeing what you did and your results.

    -=Bob=-
     
  4. Bob U

    Bob U Stunt Coordinator

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    Ooops. Disregard. Just found your topic 8^)

    -=Bob=-
     
  5. Bob U

    Bob U Stunt Coordinator

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    Ok, tried the turn on whump.

    When the Sunfire subs are in "standby" mode, there is very little problem,. But if they are on, the whump is a full excursion of the woofers. Unacceptable. Consequently, if I turn my system off, then on again before they have 5 minutes to go into standby again, I have a problem.

    QUESTION:

    Does anyone know what the problems might be if I hooked the subs onto the delayed turn-ons section of my Monster Power strips? Sunfire seems to have designed the subs for always on. Must be a decent reason NOt to have them turned on and off via a power strip, no?

    -=Bob=-
     
  6. Bob U

    Bob U Stunt Coordinator

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    Ok. BFD is in the rack. I decided to hook it up to an always on socket on the power strip though I would have much preferred a way to block the DC should there be a power outage. Didn't need a cheater, btw.

    Bought a little bit of static cling window tint and cut a piece 1.5" x 7" to cover the display. Works just fine.

    I set the input level by using my proc subwoofer test tone. I figured that was -20dB and I wanted an extra 10dB headroom for the LFE, so I set it for a SOLID on at -30 on the BFD. Make sense? I'm assuming the LFE test tone is -20dB as the other channels are.

    I'm off to go set filters and post a graph. Back in a little while.

    -=Bob=-
     
  7. Wayne A. Pflughaupt

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    Bob,
    Post the following information and I’ll make some recommendations for EQing your sub:
    • What is the total cubic ft. of your listening area? Include all space and/or rooms that open to the HT area (i.e., cannot be sealed off via closed doors).
    • What is the crossover frequency of your sub/receiver/pre-pro, etc.
    • What are the specifics of your sub(s) – driver size, amplifier power, etc.
    For the delay situation: If the Monster strip has at least a 15A rating, you can probably safely use it for the sub – unless you have it plugged into your receiver. If that is the case, you need a strip that plugs directly into the wall and is triggered by the receiver. If the Monster doesn’t do this, the Adcom ACE-515 does. I believe some Panamax products do, too. You can get the ACE-515 used on e-bay for $75-125.
    Regards,
    Wayne A. Pflughaupt
     
  8. Bob U

    Bob U Stunt Coordinator

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    HI Wayne,

    Thanks for that offer.

    In terms of volume, its impossible to calculate. Great room, connected to dining room, open door to kitchen, wide open to hallway and stairs going upstairs, etc. There is no way to tell and no way to find a spot to stop measuring.

    Crossed over at 80Hz on the pre/proc. Subs are 2 Sunfire True Subs MKII's. 2700 inflated watts, 8 inch drivers, etc. I'm sure you know them.

    Just tried my first settings and the results are NOTHING like I would have expected. I'll post the graph here in just a moment and definitely will apreciate advice. I'm just going to go downstairs to be sure the filters are indeed set as I think they are. I di raise the sub levels after adjusting the input to the BFD, hence the general level change on the graph.

    And I called Sunfire. They definitely recommend always on for the subs and not connecting them to a timed power conditioner.

    -=Bob=-
     
  9. brucek

    brucek Second Unit

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    Wayne,

    I don't want to hijack Bob's post, but perhaps he could benefit from the answer, because I think he has the same question.

    1. What benefit is gained and what different recommendations would you make once you know the total cubic ft. of the listening area?

    2. Does the connecting space through a door have an equal impact on the sound as does the primary room? If it does, I would almost have to include the total floor space of my three bedroom house, because from my living room (a.k.a. HT room), the connection is open to the dining room, kitchen, hall, bathroom and three bedrooms. Where does the influence of each room end?

    Bob, check that everything is working by adjusting one filter way off (-24db) and make sure it does indeed lower that frequency... Then you know your good to go..

    brucek
     
  10. Bob U

    Bob U Stunt Coordinator

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    Ok, I'll assume for a minute that the filters are set as I say below. I need to go out so can't check just yet.

    Large jpg below. Sorry, but I am in a hurry to leave and anxious to hear what I did wrong when I get back 8^)

    Image deleted - see below

    -=Bob=-

    Ps. I'll delete this graph when I get home and post the next one.
     
  11. Matt Barrett

    Matt Barrett Extra

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    Bob,

    Since you have two subwoofers, how are they positioned in the room? Are they both in the same place?

    Perhaps you should try testing the response of each sub independently, and then use both channels of the BFD to equalize each sub independently.
     
  12. Bob U

    Bob U Stunt Coordinator

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    They're in the front corners, Matt.

    I may try that as a tweak when I get a little closer. Right now, I am doing something fundamentally wrong to get the EQ curve I just got.

    -=Bob=-
     
  13. Bob U

    Bob U Stunt Coordinator

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    Ok, just found my math errors and killed the large charts above. These are my new settings and readings. I lost more at the extreme bottom than I would have expected, and I am not yet anywhere near as smooth as I would like, but there is definite improvement.
    .Images deleted. See new curves below.
    Appreciate advice as to what settings to change to tweak this out a little more. For example, some of the postings I have read here have selected center frequencies that didn;t seem to me to be the obvious choices. I'm curious why they were not at the center of a bump, how they got selected and how that would apply to my situation.
    -=Bob=-
    PS. Bruce - you are exactly right. We seem to have the same situation with the layout of our houses.
     
  14. Wayne A. Pflughaupt

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    Bob,
    I’m familiar with parametric EQs, I since don’t have a BFD I’m not familiar with its peculiar nomenclature and designations. For instance, I have no idea what the information in the “SETTINGS +FINE” column mean. Also, I speak “octaves” for bandwidth, not “Q-factor.” Please keep this in mind, so I can better help you.
    Brucek,
    I ask for a number of reasons.
    Living room, dining room, game room, kitchen, etc. – if it’s open to the theater area, it’s acoustic space the sub has to fill. Logically, it takes significantly more power and “woofage” to fill a large open, area than it does say, a 10’x12’ bedroom – especially at the lowest frequencies since there is less “help” from the effects of cabin-gain. It’s the same reason that they need thousands of watts in concert hall PA systems, and seldom attempt to get response below 40Hz.
    In addition, knowing the totally room volume helps me determine a house curve. As you probably know, larger rooms need less than smaller rooms.
    This is of course very unscientific. The only thing I have as a reference point is my own curve/room data. It would be nice if some other people dropped me their own curve info, but no ever seems to get back to their “Please help” thread with that info.
    Thus knowing about the room and the sub/amp combo helps me determine how realistic it is to achieve response down to 20Hz at reference levels, and how much EQ the system can handle. Remember, anytime you equalize you place greater demands on the amplifier.
    As to how much of impact an open space has on the primary room, that’s a little tougher to determine, but I expect it depends on the size primary space as well as the size of the openings.
    In my situation, the kitchen and dining room are behind the living room, and they open with no walls to the living room (a wall between the kitchen and dining room ends where the living room begins), so it is essentially one huge room. There’s no escaping the reality that the subs (as well as the mains) must be capable of filling the entire area.
    I had an opportunity to visit a local Forum member this weekend with an very different situation. His theater is in a smallish room off the entryway, only a few feet wider than the viewing sofa. Sitting facing the equipment, there was an opening (to the entryway) perhaps 8’x9’ at the front right and a regular-sized doorway at the rear of the room (about 6-8’ behind the sofa) going to the kitchen.
    Thus, most of the room had actual boundaries (walls). In addition, his sub was in the front left corner, so the seating area benefited from some near field and boundary reinforcement. I expect this situation would be more like “leaking sound” and would “contain” the lows significantly better than my room, benefiting from a certain amount of cabin gain. The effect of cabin gain could certainly be less than if the room was sealed, but at the same time would certainly be more than there no walls at all between the open areas.
    Is that clear as mud? [​IMG]
    Gee, this gets me wondering, given that I can’t tell an EQ candidate’s actual situation (unless he posts a room diagram), if I should even bother guessing at house curve...
    Regards,
    Wayne A. Pflughaupt
     
  15. Bob U

    Bob U Stunt Coordinator

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    Wayne,
    You can see a diagram of my room here:
    Room Diagram
    No problem speaking octaves. I can convert. And the setting plus fine is just Behringer's way of setting the center frequency for the filter. For example, 20+4 becomes 21Hz.
    I have tried several settings since my last post and getting closer, but still nowhere close enough. Will post another chart a little later tonight. Off to make a few more changes.
    -=Bob=-
     
  16. Bob U

    Bob U Stunt Coordinator

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    Ok, getting tired now, but best curve yet below. I have some changes planned to try in the morning now that I am learning just how my changes effect the curve.
    Images deleted. See new curves below.
    -=Bob=-
     
  17. Wayne A. Pflughaupt

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    Bob,
    Wow, this is really a severe room – possibly the toughest oneI've ever dealt with. It took me at least three hours to come up with these filters!
    However, according to my calculations this will significantly smooth response and give you a 9dB house curve from 100 to 32Hz. In addition, the 15dB hole at 40Hz will (hopefully) be reduced to only 6dB. Only the BFD could have tamed this room, and as you can see there are numerous layered filters – eight in all.
    A few guidelines: For each filter I will let you know what the technical outer parameters (o.p.) are, that is, the furthest point from the center frequency that should be affected by boosting or cutting the filter. For instance, with a 1/3-octave filter centered at 63Hz the outer parameters would be at 1/3-octave in each direction from center – 50Hz and 80Hz. You can expect some “over spill” – it is typical for a filter to cause an affect a little wider than its technical “boundaries.” However, it is very important to keep an eye on the readings of the outer parameter frequencies. The “over spill” effect will vary with the amount of boost or cut, but there should never be a change there more than 2dB for the filters we’re using here. You could expect to see about a 2dB effect at the parameters with gain changes (i.e., filter boost or cut) of 8-9dB. For filter gain changes of 5-6dB expect about a 1dB change at the o.p., and less than 1dB for gain changes of less than 4dB. If for some reason you get more than the expected changes at the o.p. frequencies, tighten up the filter a little.
    If you see a tremendous gain change at the o.p., that means I made a clerical goof while experimenting with different filters on paper. Probably the goof will be a filter twice as wide as it should be, so reducing the bandwidth by 1/2 should put you back on track.
    Okay here we go:
    • 1/6-octave, 22Hz, -5dB. The o.p. frequencies are 20Hz and 25Hz.
    • 1/3-octave, 32Hz, -9dB. The o.p. frequencies are 25Hz and 40Hz.
    • 1/3-octave, 50Hz, +8dB. The o.p. frequencies are 40Hz and 63Hz.
    • 1/4 octave, 94.5hz, +8dB. The o.p. frequencies are 80Hz and 111Hz.
    • 1/6-octave, 71Hz, +2dB. The o.p. frequencies are 63Hz and 80Hz.
    • 1/3 octave, 111Hz, -4dB. The o.p. frequencies are 89Hz and off-scale.
    • 1/6 octave, 40Hz, +8dB. The o.p. frequencies are 36Hz and 45Hz. NOTE: If this results in a gain change of only 2-3dB at 40Hz, then you have a room null, in which case you should skip this filter.
    • 1/6-octave, 56Hz, +3dB. The o.p. frequencies are 50hz and 63Hz.
    These changes will bring the overall level of the sub significantly lower than the readings you have given for the mains - so you will have to turn the sub up. Your reading at 32Hz should be 10dB higher than 400Hz, or 8dB if you think a slightly reduced house curve sounds better.
    Regards,
    Wayne A. Pflughaupt
    P.S. if this works and you’re feeling generous, I like Luby’s. [​IMG]
     
  18. Bob U

    Bob U Stunt Coordinator

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    Hi Wayne,

    Wow. Thanks so much for the time and thought you put into this.

    The first part of your post was cut off. Anything significant that is missing?

    Second, most folks here advise against boosting any frequencies to avoid losing headroom. Do you not subscribe to that theory? I'll wait for a little comment here before trying any boosts. I have avoided that in my tests so far.

    Third, I have a read a bit about a "house curve", but since my system is both (and equally) a HT and Music system, I *think* I would much prefer a flat response rather than low end boost. I'm open to other thoughts if you think this is equally valid for high quality music as well as HT.

    Also, the Behringer has the ability to select almost any Q, so I am not limited to 1, 1/2, 1/3, 1/4 octave, etc. if there is anything hone a bit finer.

    And last, what is "Luby's"??????

    -=Bob=-
     
  19. Wayne A. Pflughaupt

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    Bob,

    I fixed the post. My psycho computer needed a re-boot.

    In your situation, it will be impossible to achieve smooth response without applying some EQ boost.

    Here’s some thoughts on headroom that I posted a week or so ago in another thread:
     
  20. Bob U

    Bob U Stunt Coordinator

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    Wayne,

    That third filter at 50Hz should be MINUS 8dB, not PLUS, correct? And if so, shouldn;t it be tighter?

    -=Bob=-
     

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