My latest subwoofer adventures...

Discussion in 'Archived Threads 2001-2004' started by Bob U, Jun 24, 2002.

  1. Bob U

    Bob U Stunt Coordinator

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    Been quite a while since I posted about subs and thought I would bring things up to date.
    Some of you might recall, I had a pair of Sunfire Mk II's and was less than thrilled. I learned about the Behringer Feedback Destroyer here and improved things a bit. But it never sounded like anything folks here were describing for their bottom ends. Especially SVS owners.
    Posting here got someone about a half hour away to invite me over to auditon his SVS 25-31. Amazing. So I immediately sold the Sunfires and bought a pair of SVS 25-31's tuned to 22Hz.
    Unfortunately, it was just a minor improvement *in my room* and I spent weeks tweaking, emailing SVS back and forth, trying lots of things. Getting frustrated, I hauled one over to my new friends and matched levels and phases, checked curves and swapped them out in HIS room and mine sounded even better than his. Even without any BFD EQ. So, I learned that I have a problem room. And believe me, I tried corners, away from corners, walls, one sub, two subs, two side by side, two in opposite corners...you name it. What I am hearing is that a concrete slab detracts from sub response and a wood floor enhances it - which is just the opposite of what my sense of logic says, but it seems to be true. I never got "pressure" or that "tactile sense"...or maybe just a touch of it.
    I have to say it is rare if not impossible to find the kind of customer service that one receives as an SVS customer, but, alas, we ran out of ideas and decided to return the subs under the 45 day guarantee. There was no way of knowing if a 20-39 or 16-46 might have been an improvment and we had all become a bit frustrated after 80 some odd emails and even a call or two.
    So, I bought a HSU VTF-3. It was due to arrive Friday, but got into Sacramento and was promptly lost by UPS. How do you lose a 93 lb subwoofer?? Be that as it may, it arrived today.
    It goes lower than the SVS (and the Sunfires). I don't know how that would compare to the 20-39 or 16 46, but definitely lower than the 25-31 tuned to 22 Hz. And one thing I had learned from all my prior tests is that I got better results with one sub than with two. No matter how they were placed. And one SVS or one Hsu seems to be more than enough for me. Even at reference level. I never bottomed either one.
    The Hsu sounds very good. Better than anything else I have tried. I get a little more tactile and pressure, though not what I know is possible in other rooms. But more than I have had in my room before. It sounds very good on music, though I am getting just a touch of bloom on kick drum, And I have one suckout that is new to this sub / position for me that I can't seem to cure. But all in all, its not a bad curve for the first day tweaking. And I will go back and touch up once the sub has broken in.
    And just as an added perk, it matches my Westlake mains fairly well in finish so it looks a little better in my room. I'l lhave to take a new pic and post in the next few days.
    But, for now, here's my first day's curve. Happy to answer any questions.
    -=Bob=-
    [​IMG]
     
  2. Bob U

    Bob U Stunt Coordinator

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    Ok, here's a bad flash panorama. I'll do a better one in daylight [​IMG]
    [​IMG]
    -=Bob=-
     
  3. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    Hi Bob,
    Glad you got something working out in your room a little better. It doesn't surprise me the 3 is going lower than the 25-31s..I think the 3 in max extension mode is tuned around 18hz(not sure though---just what I read somewhere). When Bob sez he and I spent a few emails trying to optimize the PCi subs...he isn't kidding [​IMG] Hopefully someone will pick up one of the new PC+ units near you Bob and you guys can A/B it against the 3....that should be interesting.
    TV
     
  4. David Ison

    David Ison Stunt Coordinator

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    BOB
    just curious, how did you go about placing and setting up your sub?
     
  5. Bob U

    Bob U Stunt Coordinator

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    Well, I knew from experience that the left corner has a smoother response than the right corner. And I have floor to ceiling bass traps and this sub has rear ports. So I wanted it away from the corner / walls some. I figured 1-3feet min and max.

    I placed it under my left main, as in the picture, then moved it forward and back measuring primarily phase response looking for the best curve pre EQ. Also watched out for refraction from the mains off the baffle of the sub.

    Where it is now is not yet chisled in stone, but works ok. And with the BFD, you can see just how I was able to smooth the room curve.

    I may try moving it some to see what I can do about the dip at 90Hz that just won't EQ out.

    -=Bob=-
     
  6. ling_w

    ling_w Second Unit

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    Bob,

    So the graph is before and after BFD?

    Do you have a graph that goes lower than 16hz, so we could see how low they really go?
     
  7. Bob U

    Bob U Stunt Coordinator

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    Yes, that is before and after. I still want to tweak a bit more, probably after break-in. But I'd like to see the dip at 18 (which can't be affected by the BFD) and the dip at 90 flattened out a bit.

    I can't see any reason to measure below 16Hz, actually. And not sure if the RS meter has a correction value for under 16Hz. And then realize, this is VERY room dependent and what I measure may not be what anyone else will get at frequencies that low.

    -=Bob=-
     
  8. Mike Kao

    Mike Kao Second Unit

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    Wow that things looks surprising tiny and discrete! May I ask where you purchased it?
     
  9. Bob U

    Bob U Stunt Coordinator

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    I assume you mean the sub?? If so, its not that small...about 16 x 20 x 23".

    I bought it from AV123.com. Good service.

    If you meant something else, just let me know.

    -=Bob=-
     
  10. KevinHunt

    KevinHunt Stunt Coordinator

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    It looks tiny because Bob has big a** main speakers [​IMG]
     
  11. Wes

    Wes Screenwriter

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    Just an observation, but your mains look as if they are pointed to a sweet spot around 4' in front of your tv. Is this just an optical illusion with the photo? If not perhaps a laser pointer pen would help to aim them!

    Wes
     
  12. Bob U

    Bob U Stunt Coordinator

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    Actually, that's an illusion. They are **meticulously** aimed 2' in front of my listening position and image incredibly. I took hours to place them and in this manner, the sweet spot is about 3-4 times wider than it would be normally.

    -=Bob=-

    PS. They actually converge about 8' in front of the TV and I sit about 10' from it.
     
  13. Bob U

    Bob U Stunt Coordinator

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    Ok, spent a few more hours today and got a new curve. With the exception of 89Hz, this is the flattest I've ever been able to achieve in my room.
    Now the question is: Is flat better sounding than my usual "house curve"?? Hopefully I'll answer that tonight.I'm running the sub about 4 dB hot, btw, and will play with that as well tonight.
    -=Bob=-
    Disregard (SLAM) on the chart label. This is still MAX Extension. Shows before and after.
    [​IMG]
     
  14. Lewis Besze

    Lewis Besze Producer

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    Bob,
    why do you want to "cure" the 89hz dip?
    Is you sub has reproduce "bass" that high up?
    Is your speakers[which looks capable,but don't know about the surrounds]high passed, higher then 80hz?
    Nice flat response there though![​IMG]
     
  15. Bob U

    Bob U Stunt Coordinator

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    Thanks! About 4 or 5 hours tinkering to get that.

    Well, I hate to have a 10 dB dip in the curve. I am crossed over at 80, and both the subs and mains are responding at 90 Hz so it has to be a room phase problem. I doubt I'll ever get that out.Mains are good down to 50Hz, btw.(-3 dB)

    Just listened and the sub sounds fabulous now. Better flat than ever before with a house curve. More pressure and tactile. I'm tempted to goose it just a dB or two more.

    But kick drum on music is not "tight". A little ringy and I'm not sure where that is coming from. Anyone have an idea what frequencies would cause a kick to bloom and ring just enough to make it annoying?

    -=Bob=-
     
  16. Bob U

    Bob U Stunt Coordinator

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    Just a little update:
    I am liking this a lot for DVD's. Seems that I prefer flat rather than a house curve OR that the low end extension of this sub is making the difference for me. Not sure which, but DVD's sound fabulous.
    BUT, I can't nail that little problem with music. Best I can describe is that a nice, tight kick drum with a damped "thudding" attack (as heard in headphones or without the sub) has a little "tympani" effect to it and it rings and sounds like the head is too tight and undamped. I have a tough time telling whether this is an upper harmonic or lower fundamental that isn't heard without the sub online.
    Now I know that when you want to tighten up a kick in the recording process you do a little boost at 80 and 120Hz, but where is the bloom that needs to be reduced? Anyone have an idea how to isolate this?
    And one last note: I actually can hear this sub breaking in. Never noticed that with my other subs, but after 10 or 15 hours, it is already mellowing and feeling quicker, more balanced. AV123 tells me that it takes 150 hours for break-in, so I'm looking forward to it getting even better. And I'd love to hear this sub in a "good room" [​IMG]
    -=Bob=-
     
  17. Lewis Besze

    Lewis Besze Producer

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    Bob,
    In my experience the critical fr range is the 40-50hz for kickdrum[fundamental],however it's not just the fr response alone that can make it "work".
    I have a custom sub built originally with a Tempest,and 2 15" pr's,I really liked that sub as is but the kick drum just didn't "kick",so I tried a different driver [Blueprint 1503],and voila it worked great.
    I know that my anecdote not exactly much of a help but what I'm trying to say is that there isn't an easy answer to that not to mention we're talking a very subjective part of this hobby here.Good luck though and keep us updated on you venture.
     
  18. Bob U

    Bob U Stunt Coordinator

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    Ok, spent about another two hours today just to do a final filter tweak and unless the FR changes as the sub breaks in, I think this is as good as I can do. I also included the filter settings this time in case anyone is interested.
    Still have the kick drum bloom. I emailed both TV from SVS (who says he has setup VTF-3's I understand) and Dr Hsu (who is on vacation until Friday or Monday) for any advice.
    -=Bob=-
    [​IMG]
     
  19. Richard_M

    Richard_M Second Unit

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    Bob,

    Are you happy with the output of one VTF-3, and do you think 2X would be an overkill. The reason for asking is that it appears alot of SVS users tend to go with 2X subs.
    Obviously I realise that room size and personal preference has alot to do with the choice.

    The other question I have is the sub quiet, when no signal is present. i.e. is there any noticeable hum or hiss from the speaker. I have noticed in photos of the unit, that it has a mains earth. I use RG6 quad shield coax for my interconnects from my BFD, but my current M&K's don't have a Mains earth.

    The VTF-3 is not due to be released in OZ until Mid July, and I'm just trying to get as much info before buying one (or two).

    Regards,

    Richard
     
  20. Bob U

    Bob U Stunt Coordinator

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    Yes and yes.

    What I found with 2 SVS's is that it was more difficult ***in MY room** to get a decent response. One always sounded better. So I only bought one VTF-3 and it seems to be plenty. At least for me.

    I needed a cheater on the VTF. Did not on either the Sunfires or the SVS. Both Sunfires and SVS were DEAD quiet. VTF has the tiniest bit of hum, even with the cheater. Next to not noticeable

    -=Bob=-
     

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