What to do with old ISD drivers

Discussion in 'Home Theater Projects' started by Jason ) H, Jun 19, 2006.

  1. Jason ) H

    Jason ) H Auditioning

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    Hi all,

    I am new to the forum.

    I will be upgrading my pb2-isd to the nsd drivers[​IMG] , and was wanting some suggestions on what could be done with the isd's. I was thinking perhaps another subwoofer, but what dimensions and type of box, amp etc... Perhaps a car application would be feasible. I like to go to the drive-in from time to time, and It might be cool to have some good bass there.

    I also have an old set of cerwin vega speakers that have 12" drivers which I use for stereo listening. Would it sound good if I took those out and replaced with the isd subs?

    Any thoughts...
     
  2. Brent_S

    Brent_S Second Unit

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    The dimensions needed to build a box for your ISD are sitting right there in the form of your PB12 cabinet. Pick up a suitable 300ish watt amp somewhere and you're in business.
     
  3. Jason ) H

    Jason ) H Auditioning

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    Thanks Brent.
    I Would probably also need to put 3 3" ports in the box. Not sure how thick it would need to be, the SVS box seems to be really thick (heavy duty). Anyway, if anyone has any suggestions on what to build the box out of for best sound quality, please let me know.


    Also, Would I need to line the inside of the box with any type of sound dampening material?

    Thanks
     
  4. Brent_S

    Brent_S Second Unit

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    When you take the old driver out to do the upgrade, all should be revealed. Have a notebook, tape measure and camera handy.

    The box is MDF, I believe. The thickness should be measurable with the driver out, although the baffle could be thicker than the remaining cabinet walls. If you're really curious, pull the amp out for a second data point.

    In the various photos of SVS internals I've seen, they appear to use plain fiberglass insulation batting. Again, you can measure the thickness while you have the driver removed.

    What's really most important is to determine the net internal volume of the cabinet. You don't really need to duplicate the SVS cabinet, just build something that yields the same net internal volume with equivalent or improved structural integrity. You could even use a Sonotube type product to duplicate the cylinder subs if you want.

    The box tuning is based on the cabinet volume, so yes, you could use 3" Precision-Ports to copy the variable tuning option. Parts Express, among others, carry them. You can use something like WinISD to calculate the length, or again, just measure them while you have the box open. Once you have the internal volume, you could also look at even better breathing with two 4" ports or even a single 6" port...if you don't use the variable tuning option.

    As shown by the cylinder series, the driver works well in multiple alignments, but if you're happy with your PB12 and want to use your DIY design with it, the simplest plan is to clone its cabinet volume and tuning. For more adventure, if you can find volunteers to measure a 25-31 and 16-46 for you, you would then know the lower and upper volume limit that TomV considers suitable. Pick a volume within the range and tune accordingly, recognizing that the larger cabinet gets you a little more low frequency extension at the expense of maximum SPL output.

    Oh, yeah...when you find those measurements...share them with me. I'm buying a friend's 12.1 when he upgrades. :)


    wbs
     
  5. Jason ) H

    Jason ) H Auditioning

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    Thank you so much Brent, you have been most helpful. I'm getting just as exited about trying my hand at a DIY project as I am about getting the upgraded NSD drivers. I think I will opt to go with one large port and not mess with trying to build a variable tuning sub. I'll keep at simple as possible for a newby like me.

    I'll definately share those dimensions with you when I get them. The 12.1 driver(s) your getting is along the same lines as the NSD drivers from what I understand, so you will have an outstanding driver(s) to build with.

    Thanks again for your knowledgeable insight.
     

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