12inch Passive Sub/DIY

Discussion in 'Archived Threads 2001-2004' started by Guy Usher, Nov 3, 2002.

  1. Guy Usher

    Guy Usher Supporting Actor

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    Surfing these posts I have noticed links to DIY kits for subwoofers. . .
    I have a 981 Rotel that puts out 135x2, it is bridgable to 200 or so and I want to buy a passive sub to put on it. I want a sealed box with one or two 10s or 12s in it. It must be small, about 1.5 cu ft, and most important I want accuracy, and I want it to sound good and tight. I would be happy to keep it flat to about 25.
    The box will be used for movies but I disagree with those who say one for music and one for HT. Distortion is distortion and I want good clean bass with as little distortion as possible.
    I will , for now, be using the crossover in my Pre-Amp, later I will buy a stand alone Xover.
    Any recomendations?______________Thanks_
     
  2. Chris.Brunhaver

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    Well, in that small of a sealed box, there aren't a lot of woofer that will get that low without the help of EQ. THe couple woofers that come to mind are the Lambda SB10 and the ACI SV10 (now sold by meniscus). The cost here is efficiency as both of these are in the low 80's. Lambda has changed it cost structure to where the 10" woofer cost the same as the 15" woofers ($259), so the ACI woofer at ~$120 is pretty attractive. If you are open to a passive radiator alignment instead of sealed, you may also look at the Peerless XLS subs. If you raise the size of your box requrements to ~3 cubic feet (or get a BFD or linkwitz transform), there are a lof of good high excursion 12" drivers that would work like the Stryke AV12, PE Titanic Mk II 12" and Dayton DVC, and Adire Shiva.

    -Chris
     
  3. Dustin B

    Dustin B Producer

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    If small size is really important you may also wish to consider an isobaric arrangement with the drivers Chris mentions in his last sentence. The Adire DPL12 should work really well for this as well (here's a thread where a guy did just that http://www.harmonicdiscord.com/forum...pic.php?t=8792).
     
  4. John E Janowitz

    John E Janowitz Second Unit

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    Guy,

    If you were to go with a PR alignment instead of sealed, you have more options to get the extension you want in a small enclosure. Either the SAE1204 or AV12 in a 16" cube with a pair of 12" PR's will get you down to 25Hz well.

    Sealed box options are very limited. To get the extension you want in the small enclosure, you give up a lot of efficiency. There's really no way around that.

    An isobarik alignment as suggested will get you a smaller enclosure. Also at a loss of efficiency, and you still need a woofer that can get you that kind of response to begin with. Very few sealed box woofers will get you an F3 under 30Hz.

    John
     
  5. Guy Usher

    Guy Usher Supporting Actor

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    I didn't mention this but I would prefer a "Clamshell" configuration, I have 2 boxes now with generic drivers in them, the boxes are built well, and are very attractive. I guess you could call them compound loaded, band pass alignment.?? Hence the small size requirement. These woofers sound great but 40 is it they are down about 20 db at 30. I may have to get a bigger box. was at the Madisound website saw a 12 inch NHT kit that looked promising?? Wonder if I could buy it without the amp?? Anyone familiar with this one?
    My experiance with PRs has not been to good, however I am talking about consumer grade boxes (Klipsch) ant they were load all right but lots of distortion.
    I have the ability to build a bigger box but not the place to do it, I am going to have to find a box, line it, brace it, stuff it, wrap it, spike it etc. There must be a place here in Dallas where I can find a good box, before I get a box I guess I need to pick the driver first. I think 200-300 max, still I don't want a huge box maybe 4 to 6 cu ft?? Any drivers stand out for a box that size, I still like the clamshell configuration, I understand this will reduce the box size requirement. . .
     
  6. Jack Gilvey

    Jack Gilvey Producer

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    The only advantage to the isobaric "clamshell" configuration is to save on box size. If 4-6ft^3 is ok, then I wouldn't bother.

     
  7. Guy Usher

    Guy Usher Supporting Actor

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    Thanks Guys,
    I will look at all the above. BTW I measured the 2 subs I have, I forgot what we were trying to do when we built them, they are 72 cu inches, very small, The sound is incredible, just wont go below 40 period, if I could keep the same sound only get on down to 25 to 30 I would be a happy camper.
    I have brought home at least 10 comercial boxes and they stink, some were bottom line some were middle road-up, wasn't happy with any of them. I have been using 4 12inch Danes, but they are not mine, I guess after you hear it right (IMO) you can't go back.
    The best sounding comercial sub I tryed (in my room) was NHTs (dont remember the model number) one that had 2 tens in a sealed box, but I wasn,t happy with enough to buy it.
    Cost is always a factor but not set in stone, to do what I want may cost more but I don't want to just throw money at it untill I am reasonably sure the performance is there.
     
  8. Peter Jessee

    Peter Jessee Stunt Coordinator

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  9. Guy Usher

    Guy Usher Supporting Actor

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    Peter,
    Do you think if I used a 4 ohm DVC woofer and did not bridge it, run each side with it's own channel, the limited bandwidth might help as well. I think this little Rotel has a damping factor of about 500, almost hate to run it on a sub as it is a very sweet sounding, quiet and robust for 135x2. The subs I have it on now are 4ohm, 2 in each box, they are in a "push/pull" configuration, they are about 5 years old and I don't remember how they are wired.
    I am picking up a lot of good information here, I thought I had my mind set on doing this the same as my 2 tens but I see better alternatives alreadt.
    The Passive Radiater that I thought I didnt like is becoming more appealing as well. I like the idea behind PRs but my experiance (limited) has not been good as I stated earlier but I see now that if done right could be a good alternative, I do like the sound of a sealed box speaker wether its a sub or fullrange .
    I will look at the 12inch Titanic.
    I am moving to Ohio this month so I am about 4 weeks away from starting this project, I will put this information to work after I see the new house, at this point that is the biggest unknown.
    I know this I have "Cathedral" ceilings in this house and the 2.5 years in it I have never been able to make my system sound as good as I have heard it. . .
     
  10. Peter Jessee

    Peter Jessee Stunt Coordinator

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  11. Guy Usher

    Guy Usher Supporting Actor

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    After reading the responses I got to my original post I have decided to go with a bigger boz, around 3-4 cu ft.
    Now the driver? I like the tightness of a small woofer possibly 2 tens or maybe 1 12 or 15. Whats your opinion on 2 tens vs 1 12 or 15??
    I have the amp and will be using the Xover in my pre-amp, can I get this done and stay under 5oo bucks?
    I also have to get the box built, I will brace it, line it, stuff it, spike it, cover it, etc. I have used roofing felt in the past to line the inside? ? ?
     
  12. John E Janowitz

    John E Janowitz Second Unit

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    Hi Guy,

    If you want, send me an email. We have several woofer options that would work well for you. The new AV12's, SAE1204, our PC12 woofer, etc.

    John
     

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