DIY subwoofer question

Discussion in 'Archived Threads 2001-2004' started by EricHaas, Jan 2, 2002.

  1. EricHaas

    EricHaas Supporting Actor

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    I want a decent sub but am seriously constrained by budget and size restrictions. I picked up the Sony SA-WM40 for $150 based on reviews. Well that thing moves an amazing amount of air for a $150 subwoofer. But it isn't particularly tight, fairly boomy in fact. What do I expect at that price, right? Well I was wondering - can I purchase a new driver like the Adire Shiva driver ($135) and pop it in for better performance? If so, what is entailed? Is it easy or involved? A website link for DIY subwoofers would be appreciated. Also, I was thinking about addressing the boominess by filling the cabinet with polyfill. Is that a good idea?

    One final question, is it OK accoustically to put a subwoofer on its side? I need it to fit under a couch end table and it barely doesn't have sufficient clearance. But it fits if I turn it on its side.
     
  2. George V

    George V Extra

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    Eric,

    that could be a possibility. You may want to also consider the 12" DVC that Parts Express (PE) sells (VERY similar to Shiva). PE has it on sale for ~$100 right now, but it is back ordered. What volume box is the Sony? This would be a major factor for ANY replacement speaker you use.

    "Generally" sealed subs sound more "tight".

    George
     
  3. EricHaas

    EricHaas Supporting Actor

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    I don't know what you mean by "volume," but I think it is 16"x14"x14". It has a 12" driver. My question is, if I get a different 12" driver, will I just pop the current driver out and put the new one in, or is it more involved?
     
  4. Dustin B

    Dustin B Producer

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    I doubt the drivers will be the exact same size and have their mounting screw holes in the same place. So provided the new 12" fits properly into the hole, you'd still have to drill new holes to screw it down.

    Next problem is drivers have Thiele and Small specs, usually shorted to TS. These specification determine how a driver will perform in a certain enclosure. Different drivers perform differently in different sized enclosures. For instance a Tempest will sound awesome in a 160L+ enclosure, but if you put it in a 60L enclosure it will sound like crap. While other drivers will sound like crap in 160L+ enclosures and great in a 60L one.

    Next is whether the enclosure is sealed, ported or uses passive radiators (ports and passive radiators do the same thing just in different ways, so I'll just forget about PR from now on). Given a particular enclosure volume, it takes a certain diameter port of a certain length to tune the enclosure to a particular frequency. The drivers specs and your performance desires will determine what that frequency and diameter should be. In the case of the Sony the port will likely be too small and tuned too high for a Shiva.

    Finally the amp on the Sony will likely have a boost in the 35hz range and it will likley have a filter that will cut out the sub 30hz info. Both of which you don't want when using a Shiva.

    If you can get access to some tools, you would be much better off selling the Sony, going to the DIY section of the forum and asking for some help designing an enclosure. Then buy a Shiva and a plate amp and build your new sub.
     

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