Questions about Sonosub

Discussion in 'Home Theater Projects' started by SteveCallas, Apr 11, 2005.

  1. SteveCallas

    SteveCallas Second Unit

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    I have a few questions regarding what could theoretically be a spectacular pair of sonosubs.

    I would plan on using 2 Dayton 15" Titanic MKIII drivers - can they be mounted facing down? (the stats on these are better than the Adire Tempests)

    I would probably go with 2 24" sonotubes, 72" high, 1 driver per tube. Unsure of how many and how large of ports to use - my guess would be 3 6" ports, each about 24" long, placed on the top end cap.

    I'm thinking 3 1" thick layers of MDF sandwiched together for each endcap, 1" overlapping the tub, 2" on the inside, with 3 threaded rods connecting the top and bottom end caps.

    I would use a Crown K2 to deliver close to 1,000 watts to each driver at 3.5 ohms.

    I am not familiar with any sub creation software. If anyone sees anything obviously wrong with this configuartion, please let me know. I plan on pursuing something of this nature within the next year. Any help would be greatly appreciated.
     
  2. Dustin B

    Dustin B Producer

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    That will tune the enlosure to roughly 22hz. It's about twice the enclosure size and porting you need (way underdamped and will result in a big peak in the response right around tuning). With an enlcosure that size 1000W is about 4x as much power as you need to reach the drivers Xmax.

    At present in this price range I'd recommend this driver (cheaper and more capable):
    http://www.ascendantaudio.com/Atlas%2015.htm

    And here are it's recommended ported enclosures:
    http://www.ascendantaudio.com/Atlas%...ndations. htm
     
  3. ThomasW

    ThomasW Cinematographer

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    Forget about using the threaded rod it's unnecessary. Use acrylic caulk to glue in the endcaps.

    You can model a tube sub just like a box. Use Unibox if you need a good freeware box modeling program.

    As Dustin mentioned consider the Avalanche 15" or 18" from www.AscendantAudio.com

    Also use a lower tuning, no higher than 18Hz or so

    HERE and HERE are a couple of fairly high output tube subs I designed and built a while back.
     
  4. Mike Keith

    Mike Keith Second Unit

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    Sounds like a little over kill on the end caps and ports. the more ports you use the longer they will need to be for a given tuning, 1 6" port should do fine. Try modeling this in WinISD and see how the port length and velocity come out. I think you'll find that you need a smaller enclosure and a single port. In addition, I wouldn’t bother with more then two 3/4 thick caps on each end. I built a pair of Sonosubs with the Maelstrom 18" drivers and went way overkill on the construction and found the double end cap to be more then enough, I also put a stiffener ring in the middle and four all-thread rods through the tubes to sandwich everything together, then a coat of tar slurry on the inside to dampen. Also I put a retractable port valve on top to close the port for music listening. First things first, download WinISD.

    WinISD
    http://www.linearteam.dk/default.asp...load=winisdpro


    My DIY Sonosubs:
    http://www.geocities.com/kingdaddyke...?1078331805978
     
  5. SteveCallas

    SteveCallas Second Unit

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    Thanks for the info - WinISD was what I was looking for. Hopefully it is user friendly. I will recalculate and post my findings. I'm looking for the ability to go down clean to about 15hz at a pretty decent spl.
     
  6. Mike Keith

    Mike Keith Second Unit

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    Not sure the Titanic will do what you want, the Maelstrom's I have will just get to 115 db at 20Hz and their the SPL king AFAIK.
     
  7. Patrick Sun

    Patrick Sun Moderator
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    Besides using caulk to keep the endcaps in place, I also tapped in thin nails through the sonotube into the endcap MDF material around the circumference of the endcap. I didn't bother with using threaded rods with my 3 sunosubs either.
     
  8. Joe L.

    Joe L. Stunt Coordinator

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    Sounds very similar to my Sonosub.

    260L tuned to just under 17Hz. 72 inches tall, end-caps made from three layers of MDF, two nest inside sonotube, one wider layer outside. One 6 inch port opposite bottom mounted driver.

    Adire Tempest Driver (somewhat similar to what you are looking at) fed with 250 watt plate amp from PartsExpress.

    Joe L.

    Finished Sub:
    [​IMG]

    Not Quite finished sub. You can see end-caps and port (and me)
    [​IMG]

    Un-equalized response curve. Pretty flat to 16Hz gains a bit of respect. (I've since used a BFD to get rid of the peak at 71 Hz, smooth the slope, and implemented a nice house curve) My crossover is set to 80Hz.
    [​IMG]
     
  9. SteveCallas

    SteveCallas Second Unit

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    That's exactly what I'm thinking of doing Joe.

    Ok I played around with WinISD and I found that if I use the Ascendant Avalanche 15" driver (the more expensive one), 24" by 72" sonotube, with 1 6" port about 9.5 inches in length, feeding it 500 watts, I can get 115db +/- 2db from 15hz on up. Does this sound about right?
     
  10. Seth_L

    Seth_L Screenwriter

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    You're going to build two 533L "boxes" (tubes) each with 1 15" driver?

    The Ascendant Audio Avalanche 15 is not the right sub for those "boxes". It wants something closer to 120L.

    The Avalanche 18 on the other hand would be a nice match in that box size tuned to somewhere between 10 and 15Hz with about 600W each.

    Here's what two of them tuned to 15Hz with 600W each will do.

    [​IMG]
     
  11. Joe L.

    Joe L. Stunt Coordinator

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    I have not done any simulations of your driver, but my gut instinct is that 500 watts is more than you will need to reach xmax at any frequency lower than your port tuning frequency in that large an enclosure. I suggest you look at excursion plots vs. power you intend to use just to make sure.

    What internal volume are you thinking of for your sub? I'm guessing somewhere near 350 liters? Compared to mine, that is big...

    You'll need a real sharp rumble filter on your sub-amplifier or you will be bottoming out your new driver if you dare to turn it up on a movie with content < 15 Hz. (many movies do, but most folks don't even know the sounds exist cause their subs don't play anywhere near that low).

    My sonotube diameter is 18 inches. Makes it look a lot like a large black cloth covered water-heater. (In fact, someone suggested I paint it gloss white and attach big yellow stickers on its sides to camouflage it as a water-heater so it would blend into the basement better)

    I used a sonosub calculator that existed at the time on the web to figure out the exact tube length needed based on the driver, port, and end-cap displacement.

    An similar, improved, sonosub calculator is here: http://www.quux.net/roo/diy/sonosub/sonocalc.html
     
  12. SteveCallas

    SteveCallas Second Unit

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    Seth, thanks for the information. Looks like its much better to go with the Avalanche 18". That much spl that low is just insane. Considering how inexpensive these are compared to brand name subs, I don't see a problem of going with 2, minus the work involved. One problem I do see though is mounting a 42lb driver in a downfiring position. I would imagine I would have to go with at least 2" of endcap inside the tube and 1" outside, especially if I won't be using threaded rods. Would this weight be supportable in that position?

    Since I am continually being told that a K2 is too much power, an XLS 602 might be more suitable - 600watts x 2 into 4ohms. It has a cutoff of 10hz and considering that I would probably never get them up to 120db, I would imagine I would be ok.

    Seth, could you tell me what the dimensions of the ports you used were.
     
  13. Mike Keith

    Mike Keith Second Unit

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    If you go with the Avalanche 18" and have some attic space, consider these drivers are perfect for an IB mounted in the attic or basement. This is not for everyone but the bass quality is far superior to any box design.
     
  14. Dustin B

    Dustin B Producer

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    This will make for one hell of a home theater sub system. I'll add to Seth's comments that with an Avalanche 18 in a massive ported enclosure, although a Crown K2 would be a little bit of overkill, it wouldn't be a bad thing. You might also want to consider a QSC PLX amp. Anywhere between 600-1000W per channel at 4ohms should work nicely.

    Also for the Avalanche 18 and an enclosure that size use 3 6" ports, not 1 (they'll each have to be about 1.3m long to tune to 15hz in that enclosure). And get in touch with Chad at Ascendant Audio and find out if he's secured a source for 6" port flares.
     
  15. SteveCallas

    SteveCallas Second Unit

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    I don't like the idea of infinite baffle too much because the rest of the house acts like the internals of a subwoofer - literally the whole house will experience the bass. This is not to say that these subs I am planning on building won't shake the house, but it will be less violent.

    Does anybody think 42lbs downward firing will be a problem?

    Also, considering I would never need to play the subs at an insane db level, and the proposed extension these subs would reach, is a 10hz cutoff sufficient?
     
  16. Dustin B

    Dustin B Producer

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    Double or triple up some 3/4" void free ply or MDF and the weight won't be a problem. I'm with the others on threaded rod, did it on my first sub, haven't done it sense and don't plan too. As long as you have 3/4" of the end cap glued to the inside of the tube it won't be a problem (although more won't hurt). Even with less than 3/4" there I'd imagine the tube would rip before the cap would come out.

    What I might be concerned about is the tubes and endcaps not weighing enough. That 18" driver could cause an enclosure that light to move around. You might want to design a weighted base for them or some means of attaching them to the floor.
     
  17. SteveCallas

    SteveCallas Second Unit

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    I was thinking about that as well. I figure that if I use two layers of MDF for the base plate, and make the base plate wider than the tube (for instance, a 30" base plate) with some small rubber pads on the bottom, it should be ok. Almost all of the sonosubs I have seen use a baseplate the same diameter as the tube - since I could care less for aesthetics, I could go wider and get more stability.
     
  18. Seth_L

    Seth_L Screenwriter

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    Wouldn't three 4" Precision Ports (very flared ports) be adequate for porting purposes (per "box")?
     
  19. SteveCallas

    SteveCallas Second Unit

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    When using WinISD, and changing around the port dimensions, do I want the Vent Match number to = 0? Basically how can I tell when I have the right settings, because making changes to the port dimensions isn't changing my graph.

    Here is a stupid question. How do I connect the wire to the part of the terminals that are inside the tube? I assume I have to use rings or spades.
     
  20. Mike Keith

    Mike Keith Second Unit

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    Make sure you put some power (about 200-500w)into the simulation under the "Signal" tab, then look at the port velosity, should be below 20 m/s. Ring terminals work fine for me.
     

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