PR Sub help needed

Discussion in 'Archived Threads 2001-2004' started by Chris_Brunhaver, Jan 29, 2001.

  1. Chris_Brunhaver

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    Hello everyone, I am in need of a bit of help and advice. I am looking at building a passive sub using a TC Sounds 15HE, which I am still negotiation to buy, but should have in the near future. Some details of the driver can be found here: http://www.audio-x-stream.com/subwoof5.html and a project envolving it can be found here: http://216.150.71.139/audioinnovation/tcsounds.html. I am looking to do an EBS style enclosure, and it looks like I will be using 2 passive radiators insted of vents because of a planned low tuning, and the port lengths being too long for the intended enclosure. I have never used PRs before, and WinISD doesn't seem to have the ablility to model them. The driver is nearly identical to the Stryke HE15, and I was looking at doing something similar to their Power15 kit they sell. Info on that can be found here: http://www.stryke.com/SATser.html.
    I was planning on only using 2 of the Lambda 1400 gram 15" PRs, instead of three though. Here is a link for them: http://www.stryke.com/prs.htm. I think the design will end up somewhere between between the Power15, and the slightly smaller PR enclosure modeled here towards the bottom of the page: http://www.audio-x-stream.com/tc15v1.html. I wanted to tune the enclosure somewhere between 20 and 25 hz. I had heard somewhere that you should have ~2.5 time the displacement capability in your PRs as the driver has. Is this correct? It seems like the two lambda PRs should be adequate then. Also, how much mass, if any, do I need to add to the 1400 gram PRs to tune the enclosure. I just wanted to bounce this idea around to see if it was okay. I don't really know anytjhing about PRs, but was hoping someone could point me in the right direction. Sorry for the long post with so many links, I just didn't want there to be any confusion about what I am planning.
    -Chris
     
  2. Mark Seaton

    Mark Seaton Supporting Actor

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    Mark Seaton
    Hi Chris,
    If the driver you are reffering to is truly one of those Rudi Blondia of Audio-X-Stream was selling, I know this driver and have helped a friend build a sub with it. For the record, and to help minimize the confusion, we should really call this driver a TC Sounds TC-15. It is NOT the same as the Stryke 15HE. The frames are radically different, along with the surround. The mechanically limited travel of the two are quite different, along with the T/S parameters. The TC-15 is a very nice driver, and in the same TC family(ie not exactly same) as the Aluminum series by Eclipse(car audio). The optimal box for this sub will fall between 5 and 8 cu.ft. with a tuning frequency down below 22Hz(my oppinion). You can also use the driver in a smaller box, especially with PRs. Rudi's simulations on the web site are pretty useful, and he gives an 8 cu.ft., 5 cu.ft., and 3.5 cu.ft design using PRs. Note that most or all of the designs modeled INCLUDE the effect of a highpass filter making them 6th order designs. For using a PR system, 2 of the 15" PRs from Stryke should be plenty.
    Hope this clears things up a bit.
    Mark Seaton
     
  3. John E Janowitz

    John E Janowitz Second Unit

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    Yes, Mark is correct that these are two completely different drivers. The woofer formerly sold by Rudi at Audio-X-Stream will have a 2" p-p excursion, where the HE15 has a 3.5" p-p. Rudi has also been missing in action for about the past year or so, and is no longer selling the TC drivers to the best of my knowledge.
    If you can get one of the woofers, a 5 cubic foot box with dual 15" PR's abotu 900 grams should work very well.
    John
     
  4. Chris_Brunhaver

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    Hi guys, thanks for the quick responses. Yeah, I know someone who has a couple, and I am probably going to buy one or two. I do understand that the Stryke SAT 15HE is a different driver all together, I just meant to say that I was looking to do something similar to their Power15 passive radiator sub. As far as P-P excursion goes, isn't anything beyond the rated Xmax not linear, and in essence not really a good thing? BTW, TC sounds does call the driver the 15" HE (for high excursion), and they claim a 3" P-P travel in their specs here on the far right: http://www.tcsounds.com/chart.html, so the driver looks pretty attractive, though maybe it is not quite as great in absolute performance.
    Thanks for the help,
    Chris
     

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