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Help Modeling theTC Epic 12

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  • Help Modeling theTC Epic 12

    I have had this driver sitting on the shelf for a couple of years and figured it was time to put it to use. I wanted to use either and RSS315 or the SD315 passive radiators since I have them sitting around too. Could it reach in to the 20s with 2 PRs driven by a BASH300 in an enclosure around 1.5cf?

  • #2
    Close, it'll reach upper 20s in 1.75 cf using a PAIR of your RSS 12" PRs. WinISD says they need 450g added mass (that's 6 of the supplied 75g disks).
    I'm not sure if that's 450g TOTAL, or 450g added to EACH PR. Shooting for a box tuning in the mid 20s.

    Using Epic 12 parms showing a Qts of 0.39 (is that what yours is?), and a B300 boost of about +1dB @ 27Hz.
    (You'd need 4 of the DS PRs just to handle the Epic's excursion - didn't even bother modeling to see if you could tune it properly.)
    Looks like it'll reach 109dB @ 30Hz @ 300w RMS. Not bad.

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    • #3
      Originally posted by Chris Roemer View Post
      Close, it'll reach upper 20s in 1.75 cf using a PAIR of your RSS 12" PRs. WinISD says they need 450g added mass (that's 6 of the supplied 75g disks).
      I'm not sure if that's 450g TOTAL, or 450g added to EACH PR. Shooting for a box tuning in the mid 20s.

      Using Epic 12 parms showing a Qts of 0.39 (is that what yours is?), and a B300 boost of about +1dB @ 27Hz.
      (You'd need 4 of the DS PRs just to handle the Epic's excursion - didn't even bother modeling to see if you could tune it properly.)
      Looks like it'll reach 109dB @ 30Hz @ 300w RMS. Not bad.
      Thanks Chris. I have one of each of the RSS and SD315. I was hoping to be able to use the SD since it is half the cost, but I will do the RSS315. I will be using the MultEQ XT32 on my Marantz 6012 to try and dial it in. I've never used it before, but interested to see what the measurements are in with room response.

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      • #4
        One Final Question, When using PE's formula for calculating sag for the RSS315 PR :

        Percentage of Sag = 24,849 / ( Xmax * FsĀ²)

        I get 2.16%. Does that mean I can use the PRs up firing and down firing, or does that only calculate for woofers? With 2 PRs, and playing with placement, would it be better to have top and bottom PRs vs on the sides?

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        • #5
          I'm interested in this subject also, as I have a TC Sound Epic 12 sitting around that I want to build with.

          On a side note, if your plans change and you want to get rid of the Epic 12, please let me know. I wouldn't mind having a pair.

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          • #6
            I'd put it in a 2.5cf vented box, using a 4" PrecisionPort (unless you can make your own PVC port w/a generous flair) that's 20" long. Fb AND F3 in the mid 20s.
            The BASH (B300 & B500) have boosts, which you don't really want for a vented design.
            The Yung amps roll off the bottom end. If you're not interested in output below 30Hz (which you shouldn't really NEED), they'd be OK.
            I'd go with Dayton's 500w amp (or if the budget's really tight, even the 250w amp would do). You'll still break 110dB by the time the amp clips.

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            • #7
              Originally posted by Chris Roemer View Post
              The BASH (B300 & B500) have boosts, which you don't really want for a vented design.
              Did you mean I don't want a boost with a PR design? My biggest reason for using PRs, is that I already have two of them (SD315 and RSS315) and I am aiming for the smallest foot print reaching in to the 20s.

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              • #8
                My previous post was for Thucker (I'm already aware of YOUR situation).

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                • #9
                  Thanks Chris! I like that idea too. I have Dayton 500W plate amp sitting around too.

                  Comment


                  • #10
                    Originally posted by Chris Roemer View Post
                    Close, it'll reach upper 20s in 1.75 cf using a PAIR of your RSS 12" PRs. WinISD says they need 450g added mass (that's 6 of the supplied 75g disks).
                    I'm not sure if that's 450g TOTAL, or 450g added to EACH PR. Shooting for a box tuning in the mid 20s.

                    Using Epic 12 parms showing a Qts of 0.39 (is that what yours is?), and a B300 boost of about +1dB @ 27Hz.
                    (You'd need 4 of the DS PRs just to handle the Epic's excursion - didn't even bother modeling to see if you could tune it properly.)
                    Looks like it'll reach 109dB @ 30Hz @ 300w RMS. Not bad.
                    How would (1) 15" PR work instead of the two 12s? I have to order a second RSS315. Thats $90. I have to have a total order of $100 for the free shipping. The RSS390 is $120. It's sag percentage is 2.5% so I could use it in a down firing position with the sub front firing. I've already cut the box though, so could I keep the same volume?

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                    • #11
                      Good call - sorta. The 15" will give the same tuning as a pair of RS 12s if you fully load it (all 7 75g disks) w/525g of added mass.
                      Now, I THINK that's over a pound (about 18oz?) of added mass, which will definitely not help your up/down-firing idea.

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                      • #12
                        Originally posted by Chris Roemer View Post
                        Good call - sorta. The 15" will give the same tuning as a pair of RS 12s if you fully load it (all 7 75g disks) w/525g of added mass.
                        Now, I THINK that's over a pound (about 18oz?) of added mass, which will definitely not help your up/down-firing idea.
                        Scott on the PE tech support helped me with the numbers. Having all 7 discs added to the PR puts the sag % at 5.8, so not recommended in the down firing position. BUT, the TC Epic is only 2.3%, so have the powered sub downfiring, the PR front firing, and it should be all set!

                        Comment


                        • #13
                          Originally posted by Chris Roemer View Post
                          Good call - sorta. The 15" will give the same tuning as a pair of RS 12s if you fully load it (all 7 75g disks) w/525g of added mass.
                          Now, I THINK that's over a pound (about 18oz?) of added mass, which will definitely not help your up/down-firing idea.
                          RSS390 came today. All the sides are cut. Hope to assemble this weekend.

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