Svs PB2+, DIY, Tumult based alternatives or what else?

Discussion in 'Speakers' started by Shane Martin, Jan 23, 2004.

  1. Shane Martin

    Shane Martin Producer

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    If a financial issue had worked out I'd living with a new subwoofer now but alas I am not and have to wait until I purchase new speakers in April/May ish in order to purchase a new subwoofer. The speakers I'm not sure on. Later on those..

    Anyway to the subject at hand. I have a large room. It's 20x25ish with a 9 foot ceiling and 2 openings which one can be shut off. The subwoofer will be corner loaded(front left) and I'd prefer a box subwoofer. My current one is an M&K Mx90 which for most folks is good but as I've lived with it a while now and heard a SVS CS+ setup, I'm wanting to upgrade.

    I've almost decided on a Pb2+ mainly due to my lack of woodworking skills. If I was to get some help from a friend or another local member who is better I have thought about looking at a DIY alternative. The question is.. Is this even worth the time and trouble?

    If that answer is yes and I can get some help then what would actually compete with the Pb2+ in terms of sheer output. From the looks of it, there is a Tumult based sub I could build but I'm a bit skeptical of its performance to take a shot at it. I was too until I heard an SVS but that is different is some ways. I would need an amp too included the the amount I'd like to spend and that would be around $1300 total. There is a DIYcable.com sub which uses a Tumult and looks an awful like the Acoustic Visions Killimanjaro which is a wood enclosure. I assume they are similar performers?

    For those wanting to push me towards IB, I just can't make it work in my room. I've tried to convince the SO and it aint happening so I need a conventional subwoofer.

    So what would you suggest?
     
  2. Edward J M

    Edward J M Cinematographer

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    If you want to go DIY, head over to the DIY section of HTF. Also look at some other DIY subwoofer sites. Research and planning is the key to successful DIY.

    I recommend using alignment guidelines from the driver manufacturer. Stryke and Adire (for example) have suggested alignments (for sealed, vented, PR) for their drivers posted right on the website. This takes much of the guesswork out and will provide good results. Adire even posts plans for box subs for the Tempest for example.

    I'm not advocating against DIY - it's a cool concept - but unless you have a decent set of shop tools and some wood-working and general handy-man experience under your belt, you may find DIY much harder than you might first suspect. People who are successful at DIY in retrospect often characterize their first few attempts as working prototypes at best, or even outright failures.

    If you want to go DIY and you are a rookie, I would definitely use a set of plans instead of trying to design/brace a box with no prior experience. AFAIK, there are no box plans released yet for the Tumult. There are a bunch of box plans for the Tempest, but in order to match the output and power of the SVS PB2+, you would need to be running twin Tempest subs.

    With that said, the PB2+ is a VERY cost-effective, plug-n-play bass solution for a largish room, and has no OEM peer as a performance value.

    Regards,

    Ed
     
  3. Dan Hine

    Dan Hine Screenwriter

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    Indeed it is.

    Shane,

    If all you want is a sub that works well then the SVS would be the easier route vs DIY. But there are also the options of DIYcable, Acoustic Visions and Rutledge Audio Design. If space is an issue at all, the Tumult based Kilimanjaro will definitely perform well and takes up 4.29ft^3 while the PB2+ takes up 7.29ft^3. That may be no big deal but thought I'd mention it.


    - Dan
     
  4. Shane Martin

    Shane Martin Producer

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    I can take the time that isn't the issue. It's knowing HOW to do it. Given either purchase I would have to learn either way right?
     
  5. Wayne Ernst

    Wayne Ernst Cinematographer

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    Shane,

    If you go the route of getting a Behringer Feedback Destroyer (BFD) to "adjust" some frequencies, this site should be very informative for you: BFD Setup
     
  6. Shane Martin

    Shane Martin Producer

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    Wayne,
    I assume that using the BFD to adjust some frequencies is what most Dan mentioned above in "Tweaking it out abit"?

    Would that be a correct assessment Dan?
     
  7. Lewis Besze

    Lewis Besze Producer

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    In the size of your room,it's pretty much "mandatory",but 2 would be my choice.
    I don't see how the SO don't like the idea of the IB,it's the most SO friendly,since there is no box visible.
     
  8. Wayne Ernst

    Wayne Ernst Cinematographer

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    Shane, that is exactly what Dan was talking about with the BFD reference.
     
  9. Shane Martin

    Shane Martin Producer

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    Would be mine too if cost wasn't a problem.

    I think if I go the Tumult route or the Pb2+ route I'd be happy either way but since neither have been measured and I haven't heard a Tumult yet, I'm very skeptical.
     
  10. Edward J M

    Edward J M Cinematographer

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    Shane, no one here wants to get into a protracted bench race, so let's all agree a single Tumult with two 18" PRs should/would hold its own against a PB2+. While the exact T/S parameters of the dB-12 driver are unknown, a Vd of about 2.3-2.5 liters is not an unreasonable assumption. Suffice it to say, either solution will provide copious amounts of clean, deep, powerful bass in that size room.

    Again, the only reason I cited the Tempest as a potentially better driver for a newbie to DIY is because Adire has released box plans for it on their website. If you can obtain box plans for a PR or vented Tumult that are proven to have good results (like the A-V Denali for example) then go right ahead and build one for the Tumult driver.

    And if DIY intimidates you, or if you are uncertain of your woodworking skills, or if you still need to buy a few of the more expensive tools for the job (like a table saw, router, jig saw, long clamps, hand sander, etc.) then I recommend you stay with an internet based OEM as the best alternative.

    Regards,

    Ed
     
  11. Shane Martin

    Shane Martin Producer

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    Due to cost IT looks like I may not be able to afford the 2 18 PR's thus I'm curious if a single Tumult would do the trick. I also agree that a bench test might not really solve anything but it would give me some insight on what to expect.
     
  12. Brian Bunge

    Brian Bunge Producer

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    Shane,

    I know Dan Wiggins has helped someone design a ported Tumult enclosure before so you don't absolutely need the PR's. If you wanted the PR's all you need is a 24" external cube made of double-walled 3/4" MDF.

    Also, keep in mind that any sub using the Tumult will be well over 100lbs. My Tumult sub weighs 130lbs. and is in an 18" cube with 1.5" thick walls.
     
  13. Edward J M

    Edward J M Cinematographer

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    "Bench racing" is an old hot rod term for people sitting around a shop debating on which of two cars would win a 1/4-mile drag based on their known specifications (like torque, horsepower, gearing, power/weight ratio, etc.).

    Of course we all know that results differ in the real world, and bench racing is often nothing more than an educated guess. The Tumult/SVS issue has been debated to death, and all I was saying is no one wants to go there anymore.

    A sealed Tumult in a reasonably sized enclosure might need some EQ (like a Linkwitz Transform) to extend relatively flat down into the low 20's. This will obviously take some serious excursion (as there is no resonator like a PR or a vent to take the load off the driver), but the Tumult has excursion in spades. You'll lose some output with a sealed Tumult as compared to a PR or vented design, but it will still play quite loud, I'm sure. Against a sealed Tumult (with no vents or PRs), the vented PB2+ might very well trump it in the output department.

    I'm not sure what you mean by "do the trick" though - you'll have to be more specific about how loud you want to play DVDs (in relation to Dolby Reference Level), if you want or need anymore advice.

    You've admitted a lack of wood working skills in your first post, so it looks like you'll need help from more experienced friends to build anything so I guess it boils down to that variable. If not, I'm quite sure you would be very pleased with the sound quality, output, and extension of the PB2+ in that size room. Good luck in your quest for great bass!

    Regards,

    Ed
     
  14. Shane Martin

    Shane Martin Producer

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    What kind of output would you guess I should get?

    I can't say what exactly I'm looking for but I was getting on a friends' dual 25/31 cs+ setup 115 in the mid 20's and that was very adequate. Then again I think my room is larger..
     
  15. Edward J M

    Edward J M Cinematographer

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    In a 4500 ft3 room, a corner loaded PB2+ running in the stock tune (3 ports open, tune switch to 25 Hz) should be able to cleanly hit 115 dB bass peaks in the mid 20 Hz region at the listening position (say 12-15 feet from the sub) without much problem. It's a big room, but it's not gigantic by any means. Hope that helps - double check with Tom V to be sure, though.

    Regards,

    Ed
     
  16. DanWiggins

    DanWiggins Second Unit

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    Hi all,

    A small sealed Tumult has been reviewed, the Exodus Audio WMD15. On the Tom Nousaine list, it holds the 4th place, and 0.7 dB seperates 2nd from 4th place. That was with a 1000W amp and a 17.5" external sealed box. Give it a bit bigger box, more power, or both and it would jump quite a ways up the list. Use ports or a PR or two, and I'd be VERY surprised if it wasn't at the top of the list.

    There's no replacement for clean linear displacement, and there's really not another driver used in any home audio products anywhere that I'm aware of that is the equal of the Tumult. About the only thing I can think of that would out-do this driver would be the servo system used in the Contrabass, or our Parthenon driver, but those are whole different ballgames.

    Dan Wiggins
    Adire Audio
     
  17. Dan Hine

    Dan Hine Screenwriter

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    Here is the list that Dan Wiggins mentioned. The Tumult based sub does A LOT better for a sealed sub that I would have thought. At [email protected] in TN's huge room is pretty good. Drops like a rock below that though (to be expected).

    Comparing it's performance against an older SVS CS sub I would expect the PB2+ to have an edge in output. A bass reflex Tumult sub would be a lot closer though. You won't go wrong with either, though.

    Personally, I would build a Tumult based sub. There is something to be said for being able to look at your sub and know you built it. And when others tell you how great it looks/sounds...well, it's a nice feeling. Also, using a BFD will give you a little more flexibility IMO. And finally, if 93db @ 20hz is enough for you (you'd probably get more since your room is about half the size of TN's) then you can have a MUCH more compact sub, excellent for WAF.

    And don't be afraid about being inexperienced with woodworking. Especially if you have some friends to help you out. Here is what my inexperience (with a little patience) put together:

    [​IMG]
    [​IMG]


    But again, you can't go wrong with either option. [​IMG]

    - Dan Hine
     
  18. DanWiggins

    DanWiggins Second Unit

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    The roll-off was primarily from the amp, which had a subsonic filter at 20 Hz. With a flat amp, like a QSC PLX3402, you get a 3 dB down point closer to 18 Hz, and strong output down to the 14-15 Hz range.

    Dan Wiggins
    Adire Audio
     
  19. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    >>>The roll-off was primarily from the amp, which had a subsonic filter at 20 Hz. With a flat amp, like a QSC PLX3402, you get a 3 dB down point closer to 18 Hz, and strong output down to the 14-15 Hz range.

    Dan Wiggins
    Adire Audio
     
  20. DanWiggins

    DanWiggins Second Unit

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    Info about the WMD15 was posted here: http://www.audiocircle.com/circles/v...t=5013&start=0 . Note that's it's a product offered by another company that uses the Tumult. Mr. Nousaine notes the rapid fall-off of the sub's amp as limiting it's low end capability. But the information was not covered in his review.

    FWIW, our own measurements in our 80,000 cubic foot warehouse show FR as +/- 3 dB from 25 Hz to 160 Hz (upper limit of the crossover). When the internal 1000W amp was bypassed and an external pro-sound amp was used, frequency response extended down to 18-20 Hz Hz. In a typical room, response should be flat to the mid teens.

    Dan Wiggins
    Adire Audio
     

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