Do I really need a parametric EQ for my new SVS PB12-Plus/2?

Discussion in 'Speakers' started by Dan_J_H., Mar 28, 2005.

  1. Dan_J_H.

    Dan_J_H. Stunt Coordinator

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    I should be taking delivery of my sub this week. I wonder how many other owners of this sub have purchased a parametric EQ. Should I first do the Avia/SPL set-up and see how it sounds? Or is getting a parametric EQ a no-brainer? I'm a total newbie to EQ's and would have to learn how to use them. I don't want to waste my money on an EQ if I don't really have to. From what I have read here, the BFD (Dsp1124p) parametric EQ is a better (less expensive option) than the Rane PE-17 found on the SVS site.

    Dan
     
  2. AlanZ

    AlanZ Screenwriter

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    I'm in the same boat as you. I'm very familiar with SVS subs, but I've never EQ'ed any of the ones I've had. The PC Ultra has an equalizer built into it, so I'd be interested to hear what that can and can't do.

    I imagine you'd need to use the SPL meter and some test tones to determine if you actually need one, but I have no idea about the differences in equalizers.
     
  3. SethH

    SethH Cinematographer

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    I would certainly take your chances calibrating it normally before buying the BFD. But unless your room has great acoustics you're going to have some peaks and nulls. It's up to you if fixing those is worth the money or not. But certainly wait and run a frequency sweep before you drop the extra cash. Play with placement also, if possible.
     
  4. Brian L

    Brian L Cinematographer

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    Well, unless you are listening outdoors or in a huge, commercial theater sized room, you need an EQ for the sub.

    Its not usually the sub that makes this so, its the room and the way low frequencies behave in the room.

    Now, you may get lucky and find that you can place your sub and your seat in a spot where the normal peaks and valleys are either minimal (not likely) or non-offensive, but I don't think there is anyone here that bought a BFD (and took the time to learn how to use it) that regrets it.

    BTW, you will need to use something other than AVIA to get a picture of the bass in your room.

    Check out this site, where you can get some test tones that will allow for a reasonably accurate picture of your room's low end FR.

    http://www.snapbug.ws/bfd.htm

    BGL
     
  5. David_Rivshin

    David_Rivshin Second Unit

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    I would first take some measurements before deciding on whether you need an EQ. If you end up having a pretty flat frequency response curve, then you can save yourself a few bucks. Of course the problem is that almost noone has a good frequency response curve in a normal environment, unless they put alot of thought and money/effort into room treatments.
    If I had to choose between the BFD and the Rane for a sub, I'd pick the BFD, just because it's much cheaper and it gets the job done. While I'm sure the Rane is a better EQ sound quality wise (it's fully analog if I understand correctly), I don't think it a big enough jump for a subwoofer to justify paying the price. If I was looking for an EQ for my main speakers, the Rane would definately come out ahead. Two things I notice are different between the BFD and the Rane:
    1) The Rane can go to 10Hz center frequency, the BFD only goes down to 20Hz. This can be useful if you're trying to boost the low end artificially, but I don't think is a dealbreaker.
    2) The Rane only has 5 bands, while the BFD has 12 bands per channel. 5 is usually enough, but the obsessive tweaker can easily use more.

    Lots of folks around here are very familiar with the BFD, and if you search the forums you find lots of good info, and links to helpful spreadsheets. But for now just grab your basic RadioShack SPL meter and some test tones, and plot your in-room frequency response curve.

    Oh, and BTW, congrats on your sub. I'm quite jealous, and I'm sure you'll enjoy it.

    -- Dave
     
  6. Eric Ha

    Eric Ha Stunt Coordinator

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    As I just sent a PM to Alan, if you have multiple peaks and or nulls in your in-room response, a PEQ will GREATLY improve your sound quality. I have a SVS PB12/Plus2, and I had a deep drop at 40hz which meant I was hardly even hearing those sounds, and a big peak around 60hz which meant that was mostly what I WAS hearing. Now I have a flat response, with a small rise as the hz drops, and am hearing what the artist, or moviemaker, intended for me to hear. Much more refined and powerful sounding.

    Of course, take measurements before you buy a PEQ, to see where you are at for in-room response, and use the correction factors if using a Radio Shack spl meter.
     
  7. GregBe

    GregBe Second Unit

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    So what would you guys consider a small peak or dip not to worry about, or one that would warrant an equalizer for?

    Greg
     
  8. SethH

    SethH Cinematographer

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    I would say anything more than 6db in either direction will be pretty noticable. But when you do the frequency sweep you'll be looking at the SPL meter and seeing the actual numbers, but your ears will likely tell you if it's something that will cause problems or not. If you have a really bad peak (let's say 12db) that could certainly make listening uncomfortable if it occured at a certain frequency and you were listening at reference to begin with. If you stay within 6db of flat (which is probably unlikely), AND you're happy with the way it sounds, then I'd say you're fine without a PEQ.
     
  9. Bill Polley

    Bill Polley Second Unit

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    With my BFD, my sub is flat within (+-) 1 db from 20-85 hz, and is down only 3.5 db at 16 hz. To tell you the difference in sonic terms...without the BFD the SVS is loud and clear, SLIGHTLY boomy on bass plucks and kick drums. It just sounds a bit boomy and muddy, with a few bass notes unintelligable while bass notes in other areas will be loud enough to slightly overpower the rest of the music for a moment.

    When you are used to hearing the music this way (you are used to it when you don't EQ) you think it is normal and sounds great. Once you use the BFD correctly, it is a night and day difference. Everything sounds better. Every note, both bass and treble, sounds clearer. Bass plucks are solid and pronounced without overpowering the rest of the music. Bass attacks seem "faster" (not really faster, but many people describe it this way...really the lack of boominess and room resonation just make it seem quicker to attack and decay). Treble sounds are not drowned out by the one note boom of a large peak.

    I start by measuring (with a Rat Shack SPL meter) every frequency from 16 hz to 120 hz. I apply the SPL meter correction values to get actual response. Then I start at the bottom of the spectrum and correct the biggest problems. This generally takes 4 or 5 of the 12 filters. Then I re-measure and correct the biggest problem areas that are left. This may take another 3 or 4 filters. I continue this until I run out of filters. The BFD has the ability to lay one filter over another, so this works out well. When I am done, the response is exceptionally flat at the listening position.

    I hope this helps.

    Bill
     
  10. Max F

    Max F Second Unit

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    I like Bill's post above and thats the way I too feel about the improvement in music. I think for movies it's not such a big deal. Many of us deal with peaks mainly, with maybe one or two nulls. These peaks actually shake the room pretty good for movies. My sub was actually more impressive for movies before the BFD; however, music drove me nuts to the point i had to really turn the sub down. I don't like fat, slow (room resonance decay) bass for music. Something to consider.
     
  11. Jack Gilvey

    Jack Gilvey Producer

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    Getting rid of room-induced colorations is essential if you want to hear your sub and not the "boom" of the room. At least a single band of PEQ is mandatory for killing the main room mode (unless you have very fortuitous room acoustics/placement), the one that makes subs sound "slow" and "sloppy". You can use more bands, but that's mainly to have a curve worthy of showing off here. [​IMG] A few SVS subs have that single band built-in.
     
  12. PeterK

    PeterK Supporting Actor

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    pardon my ignorance, but do those BFDs only equalize the Sub or do you also use it for all your speakers throughout their entire frequency range?[​IMG]
     
  13. BrianWoerndle

    BrianWoerndle Supporting Actor

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    They have the ability to equalize the entire range, but it is highly not recommended. The extra A/D D/A conversion can greatly affect the sound quality. It is not a big issue with the deep bass.
     

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