Sonosub suited for HIGH (100 or 120 Hz) crossover in a HUGE room?

Discussion in 'Archived Threads 2001-2004' started by Jeff Meininger, Aug 11, 2002.

  1. Jeff Meininger

    Jeff Meininger Second Unit

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    I have very small main speakers. The crossover is at 100 Hz, which is the low end of what the speakers manual recommends (100 - 120 Hz). With an unlimited budget, I'd just get larger mains, lower the crossover setting, and build a shiva or tempest sonosub for massive, quality bass. I'm quite happy with the performance of my little speakers, though, and my budget is VERY limited. All I want to upgrade right now is the sub.

    I'm considering my subwoofer-upgrade options in the $400 range. A friend (I value his advice highly) suggests I get two pinnacle AC Sub 100's. The reasoning is that the 10" driver will be fast enough for the high frequencies, and I can place the subwoofers next to the front right and front left speakers to help make the directional sound (high crossover, enormous room) less of a distraction. I currently have to put the sub front-and-center to avoid that... the real estate there is limited, though, and a larger sub in that location would have a lower WAF.

    I also want to consider a DIY sonotube sub. DIY seems to offer better bang-for-the-buck. I also like the look of the tube subs, and the fact that I can finish them to match the room. Most DIY sonosub advice I find by searching here, though, is suited for 80Hz or lower crossovers.

    I want very accurate, musical bass. CLEAN bass. I'm less concerned with LOUD and less-than-30Hz bass. They would be nice, but in my situation I can't have it all. I've read that a Shiva in a sealed enclosure is fast enough to perform admirably above 80Hz. Is a sealed shiva tube a good match for what I'm tying to do? Maybe a 10-incher would be faster? Maybe TWO 10-inchers (two in one tube or two separate tubes for the high-WAF left/right sub idea?) Maybe one large driver for the lows and one small for the highs with a crossover in the sub?

    I'm really open to suggestions. What driver/enclosure combo do you think would be ideal for my HUGE-living-room, HIGH-crossover situation?
     
  2. Jack Gilvey

    Jack Gilvey Producer

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    A Shiva is linear up to 450 Hz or so. A 10" woofer isn't "faster" than a 12".
     
  3. Jeff Meininger

    Jeff Meininger Second Unit

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    Yeah, I guess the Shiva is one hell of a performer. If I go the one-sub route, it sounds like a sealed shiva with a 250W plate amp is going to be the best bet. Or maybe the 12 DVC like your (Jack) green box for a smaller, higher WAF enclosure? In your writeup of the green box, you note that the sub puts out "two distinct pitches" rather than an undefined boom when listening to a particular song. That's just what I'm looking for... precision.

    Disregarding any arguments about smaller drivers being faster (plain old bunk I guess), there still might be some arguments for 2 subs vs 1, right? It makes sense to me that two subs will help fill my HUGE, WIDE room better than 1 sub.

    Parts Express is currently selling a 120W plate amp for $79, and Stryke has a 130W plate amp for $89. I imagine I could find a nice 10-inch driver for around $99. This would enable me to build TWO 10-inchers for ~$400.

    Would these two sealed 10-inchers offer better (cleaner) performance than the two vented pinnacles? Would one sealed shiva still outperform two ten-inch subs, even considering the massive air volume in the room (and adjacent rooms connected by huge openings)?
     
  4. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    The original 12 inch Titanic from www.partsexpress.com is very highly praised for quality of sound. Moreso than even the DVC and Shiva. Its got a little less excursion and is said to be easier to bottom. But if you use the 120W plate amp instead of the 250 watter and you go with a sealed box I think you'd be fine.
    Jack's right about the 10"/12" woofer "speed" (and a lot of other things, by the way). This misconception may come from commercial speakers that try to package a large, sometimes cheap, woofer in a too-small enclosure.
    I think the difference between 80Hz and 100Hz crossover will be more subtle than you're expecting. That's only about 1/4 octave difference. And crossovers aren't brickwalls anyway. An 80Hz crossover will still send plenty of subwoofer signal at 100Hz. If you can place the sub next to or between your front mains then I wouldn't worry at all.
     
  5. Jack Gilvey

    Jack Gilvey Producer

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  6. Jeff Meininger

    Jeff Meininger Second Unit

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    I don't necessarily want a small box. I just the best sub (or subs) I can build for $400, given that I'm looking for very good transient response, clean performance with a crossover at 100 or 120 Hz, and will be using the sub/subs in a HUGE room.
    I don't think I can fit two shiva, DVC, or titanic subs into a $400 budget, but I think I could make it happen with 10-inchers since the drivers and less powerful plate amps are less expensive. Maybe I'm wrong. I just want to build the best sub or subs for my budget and situation. I don't have the experience to know whether one killer 12-inch sub is superior to two lesser 10-inchers, or if two tens can fill the large room more efficiently.
    I'm not TELLING you what driver I want to use, I'm ASKING you what driver I should use. And how many drivers. And in what configuration. And with what amp(s). [​IMG]
    Thanks!
    My current idea is to build a sealed 66 liter sonotube shiva sub with a PE 250W bass-boost plate amp. But I will give that up in a heartbeat if someone explains why somethign else might be better suited to what I want.
     
  7. Jack Gilvey

    Jack Gilvey Producer

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    10" drivers worth using over a DVC or Shiva (like the 10" Titanic Mk.2 at PE) would be at least as expensive. Like I said, I don't bother. A HUGE room will be a tall order either way. The BEST sub for that budget and room would be a Tempest, but 120Hz might be a little high for a crossover.
     
  8. Jeff Meininger

    Jeff Meininger Second Unit

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    Ryan: what makes the original titanic a better choice than the MkII? Isn't the MkII pulp/kevlar cone even more stiff than the poly cone of the MkI? Or is the jury still out on the MkII? I like having so many choices!
     
  9. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    I don't have any first hand experience with the Titanics and I don't know all the particulars. What I do know is that the original is very highly praised for accuracy and transient response. And PE has decided that even though the original Titanic and the MK2 are similarly priced and the MK2 has 50% more excursion, they believe there's enough value in the original to continue manufacturing and selling them.

    Ask on the PE forum and you'll likely get a response from a PE representative. BTW, the original was a deal-of-the-day a week or two ago for something like $110.
     
  10. Jack Gilvey

    Jack Gilvey Producer

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    It's somewhat misleading that PE called them both "Titanic", as they're not really similar at all. This was obvious enough when they were introduced that PE decided to continue the original. The Mk1 will go very deep in a 3ft^3 sealed box, but not loud...not good for a HUGE room.
     
  11. Jeff Meininger

    Jeff Meininger Second Unit

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    Cool, thanks for all of the excellent advice!!

    Based on what I've learned, I think I'll go with a sealed shiva sonosub.

    Now 2 questions remain: what plate amp and what size enclosure?

    Plate amp: There are three 250W varieties that I've found... I'm not sure if bass boost is desirable in my application. Most threads I've found about bass boost are on the topic of REMOVING the bass boost for ported subs. Maybe the bass boost is beneficial in my case? I'm quite confused on this one. Which do you think would be best?

    Big bass boost: PE
    Subtle bass boost: AVA250
    No bass boost: PE

    Enclosure: I've messed around with some online javascript calculators, and found that for a Q of 0.68, I'd need 2.614 cubic feet (~74 liters). As I understand it, some amount of damping with fiberfill is beneficial, so I'd actually want to build it a bit smaller than 74 liters and stuff it, correct? Or is damping bad in my situation? Perhaps it depends on the dimensions of the tube I'll use (wider+shorter vs. narrower+taller)?

    I've found plenty a webpage with pretty pictures of sealed shiva sonosubs. The pages I've found with the nitty-gritty specs I'm looking for, though, tend to be for ported sonotube subs. Anyone have a link for me?
     
  12. Geoff L

    Geoff L Screenwriter

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    Jeff
    What are your mains and do you have stands for them already?
    What "height" is the stand at for the bottom of the main speaker to rest on?
    If you do have stands are they expensive or inexpensive?
    The reason I ask is the dual sub approach could be designed to be used as stands for the mains. Just an Idea... This assuming the box approach is not out of the picture and the stands are not mega dollar stuff that would be unused afterwards. (Now wasted money)..
    Being you said clearly ~{spl & sub 30hz extension}~ was not the "major concern" I would not rule out the 10's and smaller amps. They could be built narrower, as narrow as (the plate amp width min for mounting purpose on the back of the box) then taller, deeper, sealed, and side firing.
    Im not sure, but as long as your not looking for major spl I belive "Madisound" carrys some afforable 10's (one in particular that escapes me at the moment) in your price range that might work for your situation. The one Im thinking of was used allot. Someone built one around this driver and it was called the thrifty thumper if I remember right, and the driver sold or sells, (might discontiued) for around 59.00.
    Some may have specific model #s or tell me I am off my rocker! [​IMG]
    If not, then others might be kind enough to sim one out for you to see what they can come up with in meeting your criteria assuming this idea is something your intrested in. This in beliving the driver/or a different inexpensive 10" driver is still available and could be crossed high enough for your needs.
    This is just another idea and approach trying to follow one of your original goals.
    Regards
    Geoff
     
  13. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Most people removing bass boost are using vented enclosures tuned deeper than 30Hz. So they didn't really need the boost and they certainly didn't want the rolloff. With a sealed sub and F3 up around 40Hz anechoic you may find that boost at 30Hz is desirable. Be advised that the "6dB @ 30Hz" boost that PE advertises is really more like 4.5dB @ 31Hz. Otherwise their boost tables are fairly accurate. I've informed PE of this error but ... they don't seem to care.
     
  14. Jeff Meininger

    Jeff Meininger Second Unit

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    Ryan: it looks like they might have listened to you. I just downloaded their frequency response PDF file, and it says "Even though this is considered a nominal 6 dB boost, the actual SPL difference at 30 Hz is 4.65 dB." Not exactly 4.5, but closer than 6.

    Sounds like that amp might be a perfect match for a sealed shiva.

    I downloaded the Shiva Sealed Cabinet Applications PDF file, and I see that a 54 liter enclosure will result in Q of 0.707. The "designs" section (page 11) of that document says that they used 16 ounces of polyfill. Does this mean that the ACTUAL cabinet should be 54 liters BEFORE adding polyfill, or is the enclosure physically smaller than 54 liters?
     
  15. Jeff Meininger

    Jeff Meininger Second Unit

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    Geoff: the mains are HTD level ONE's, wall mounted. Probably somewhat comparable to JBL N series. I guess maybe I am looking for massive SPL from the sub after all. I'm not looking for really loud perceived volume for the listener on the couch, but I think the huge room requires massive SPL to allow the listener to perceive "just-right" volume. I didn't understand the relationship between listener volume and SPL when I first posted. Maybe I still don't understand. [​IMG]
     
  16. Geoff L

    Geoff L Screenwriter

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    Jeff,
    No problem, Just throwing it out their.
    Better to have that spl than wish you did![​IMG]
    Your on the right track now!!
     
  17. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    "Not exactly 4.5, but closer than 6"
    Thanks for bringing that to my attention. One of the PE guys said he'd measure it and post the results, but I thought he meant he'd post the results in the PE Tech Talk topic where we were discussing.

    My numbers say 4.44dB @ 31.26Hz but a measured result is always better than theoretical.
     
  18. Jack Gilvey

    Jack Gilvey Producer

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  19. Jeff Meininger

    Jeff Meininger Second Unit

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    The living room itself is 413 square feet, which isn't that bad, but it has a two story ceiling, connects to the upstairs through a large open stairway, and also connects directly to the dining room (no walls or doorways). It's not a cavern, but it's not an ideal HT room, either.

    The shape of the room also makes things difficult. Because of the high crossover setting, the sub must be placed front-and-center or I go nuts hearing localized bass. This front-and-center position is directly underneath the large opening to the upstairs, and permits sound to be wasted going straight into the two largest connecting rooms on the 1st floor as well. I've experimented with other sub placements, but the directional bass just makes anywhere else too irritating.
     
  20. Jack Gilvey

    Jack Gilvey Producer

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    Sounds like a job for a larger woofer.
     

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