Home Forums DIY Speakers and Subwoofers Budget GRS 12SW-4 Build

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    elliottdesigns
    Participant

    Hey everyone, I think I may have struck something pretty cool if these simulations come out to be correct. Using the GRS 12SW-4 and a mass-loaded transmission line I’m getting insane numbers. We are talking about 2.3M/S peak port velocity and under Xmax with no subsonic filter for a peak power of 175W (1st image), and just 1.9M/S when at RMS power of 120W (lower section of 2nd image). Also, because it is a mass-loaded transmission line there is little to no port resonances (top section of 2nd image). If this simulation is right, it should be a breakthrough for budget subwoofers (for those with 3D printers). Anyways, just wanted to mention it to all of you. If it works out like the simulation suggests I’ll be making a video or few on it, that might be for a while yet though, need to save up some more first. 😅

  • Budget GRS 12SW-4 Build

  • elliottdesigns

    Member
    April 13, 2022 at 10:06 am

    Of course, to make use of the lower frequencies DSP would be needed to shelve those higher frequencies, but if SPL isn’t a problem then this should be a budget killer for low frequencies if the modeling is accurate. Not to mention you’ll still have room gain left to play with, particularly if corner loaded.

  • elliottdesigns

    Member
    April 13, 2022 at 10:09 am

    BTW, for those of you interested. This is what a typical undamped ported speaker (may) look like. (SPL end is what is coming from the port, SPL sys is the combination of driver and port output)

  • joesap

    Member
    April 13, 2022 at 12:28 pm

    Very cool project. Just watched your videos, looking forward to see where you go with this.

    • elliottdesigns

      Member
      April 13, 2022 at 12:33 pm

      Thank you. I really want to make more (and probably remake that original as it was a bit long and should be in parts really). Unfortunately, as per usual university work is getting in the way. Hopefully I’ll get some time at some point though.

  • 123toid

    Administrator
    April 15, 2022 at 12:41 pm

    This is intriguing me. Curious about what you think the size of something like this would be when finished?


    • elliottdesigns

      Member
      April 15, 2022 at 3:13 pm

      If you were to use a fully straight transmission line, the whole thing would fit in 72cm(wide)*21cm(deep)*169cm(tall) assuming 3/4″ mdf. True it’s pretty massive, but mostly in height which is good for taking up a small footprint. The MDF box portion is only 72*72*21. The box could probably be shrunk quite a bit in depth and height (72cm parts), but I’d have to see how that affects absorption. Good thing about transmission lines is you get the benefits of ported and sealed. Downside is size.

  • elliottdesigns

    Member
    April 15, 2022 at 3:17 pm

    The external port structure looks pretty ugly on my current 8″ GRS 30hz design, so eventually I want to make it into an internal structure, probably through some kind of molding, I’d like to do it out of concrete due to inertness, downside is massive amount of weight which makes it wholly impractical for me, so I’m hoping aircrete which can be quite low density works out acoustically. I’m thinking it’d need a lacquer to stop it from being leaky though since it probably acts somewhat like open cell foam, but that needs testing.