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My First Sub Sim: Tang Band W8-740P

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  • My First Sub Sim: Tang Band W8-740P

    The amp will be the Dayton MCA2550D 2.1 plate amp that is currently on sale.

    Its a 1.0cuF box with a a 2" x 11" port (a bigger box is ok if need be). It will be paired with the original Madisound Recession Busters from awhile back for use as monitors in desktop PC system for a friend of mine, with mixture of mostly music but some, movies and PC gamming.

    So how dose it look? Anything I need to address or I should consider tweaking? Go easy on me .





  • #2
    Re: My First Sub Sim: Tang Band W8-740P

    Looks good to me, but that driver could handle quite a bit more power, you'll probably be clipping that amp quite often even at moderate listening levels. Other than that the box looks good.
    ----------------------------------
    Gear:
    Samsung PN50A650
    Yamaha RX-V2500
    Hafler DH-200
    AC130MKII/BG NEO3PDR Two-Ways
    RS390HF-4 w/ HPSA500

    Comment


    • #3
      Re: My First Sub Sim: Tang Band W8-740P

      Cool thanks.

      Yeah, its certainly capable of a lot more but I think that thats the amp he wants to go with since he's budget limited. Both the sub and the amp are currently on sale.

      Comment


      • #4
        Re: My First Sub Sim: Tang Band W8-740P

        Originally posted by Operandi View Post
        Cool thanks.

        Yeah, its certainly capable of a lot more but I think that thats the amp he wants to go with since he's budget limited. Both the sub and the amp are currently on sale.
        I need to recant my statement, the port area is a bit too small, you want to keep the air velocity below 10% the speed of sound, ~350 m/s

        Edit: a 4 inch port will make it safe to about 150 watts if you ever upgrade to a bigger amp.
        ----------------------------------
        Gear:
        Samsung PN50A650
        Yamaha RX-V2500
        Hafler DH-200
        AC130MKII/BG NEO3PDR Two-Ways
        RS390HF-4 w/ HPSA500

        Comment


        • #5
          Re: My First Sub Sim: Tang Band W8-740P

          Originally posted by JustinG View Post
          I need to recant my statement, the port area is a bit too small, you want to keep the air velocity below 10% the speed of sound, ~350 m/s

          Edit: a 4 inch port will make it safe to about 150 watts if you ever upgrade to a bigger amp.
          Ok, thats one thing I wasn't sure about which is why I included that graph.

          I'll mess around with it but the port lengths were getting pretty long with anything bigger than 2" to maintain the tunning freq. I was aiming for.

          Comment


          • #6
            Re: My First Sub Sim: Tang Band W8-740P

            In my limited experience, your curves predict a boomy sub.

            I'm also building a 2.1 systems based on this amp and RB-1s, and I looked at this woofer but discarded it as a poor fit. My Unibox sims are at home, but as I recall:
            - The Triska sub uses a Dayton SD215-88, which takes half the TB's power, but has 2.4dB greater rated sensitivity; sims show it playing 3dB louder at 50W.
            - in the wrong box, it's hard to get a smooth roll-off from the TB, ported or with PRs.
            This TB is a great match to one of the PE 240W sub amps, and begs for a larger (correction make that smaller) box.

            The second point, and my initial statement, deserve a little explanation. I find that flat low-frequency response on paper sounds boomy in room. Above a certain frequency which depends on room size, bass energy is stored in the room. Standing waves are set up and energy no longer dissipates as it does at higher frequencies. It's as if the room were amplifying the signal, thus the term "room gain."

            I find bass sounds best to me when I design to a gentle roll-off starting in the 50-80Hz range. I push box tuning below Fs to get the most extension, knowing that F10 can be half F3 and room gain will make up most of the difference. I want bass that moves me without booming.

            It leaves us both with the same question; where's the 2.1 plate amp with 50Wpc and 200W for the sub?

            Have fun,
            Frank
            Last edited by fbov; 02-16-2010, 05:13 PM. Reason: Actually did the modeling...

            Comment


            • #7
              Re: My First Sub Sim: Tang Band W8-740P

              Fbov -

              Intrigued by your statements regards a smaller box. I'm following this thread with interest as I have 4 of these drivers and trying to decide what to do with them.

              Until this thread I hadn't seen anyone using them. I read all the reviews and it's interesting to see that many claim good results with a multitude of box sizes.

              I'm considering a small horn but have no idea where to begin with that concept.
              'Soupy'

              Comment


              • #8
                Re: My First Sub Sim: Tang Band W8-740P

                Originally posted by J.Lee View Post
                Fbov -

                Intrigued by your statements regards a smaller box. I'm following this thread with interest as I have 4 of these drivers and trying to decide what to do with them.

                Until this thread I hadn't seen anyone using them. I read all the reviews and it's interesting to see that many claim good results with a multitude of box sizes.

                I'm considering a small horn but have no idea where to begin with that concept.
                Here is a very quick model of a tapped horn in hornresp, it looks like it has potential, I can play around and get a smoother response out of it most likely. Not too bad for 2.5 cubic feet.



                ----------------------------------
                Gear:
                Samsung PN50A650
                Yamaha RX-V2500
                Hafler DH-200
                AC130MKII/BG NEO3PDR Two-Ways
                RS390HF-4 w/ HPSA500

                Comment


                • #9
                  Re: My First Sub Sim: Tang Band W8-740P

                  May I suggest Unibox for low frequency response modeling of enclosures. You can't beat doing the analysis yourself. You can find it (and lots of other good stuff) here:
                  http://www.pvconsultants.com/audio/frdgroup.htm

                  One tip. You'll have to add the TB to the database. I find it easier to copy an existing record for a similar driver, because the spreadsheet doesn't like blanks and it's not clear what all the fields are (like default box size). The T/S specs that you do enter are the important ones, as are the specs for a PR if you model it.

                  What I'm finding is that this makes a nice sealed sub, but that it likes small, ported boxes with very low tune. That means long ports, 2-3x box size. It also opens the option of passive radiators. With the SD215s from the Triska, a single PR in a 1/2 cu ft box looks very nice, and even nicer with a little mass tuning. Unfortunately, this PR can't keep up with the TBs excursion....

                  Four of these as mini-subs is intriguing, or as the bottom end of a 3-way. Just for grins, how about a 4-driver series/parallel arrangement in a 1 cu ft box with a port in the 1m range? Modeling lets you look anything, however improbable.

                  Have fun,
                  Frank

                  Comment


                  • #10
                    Re: My First Sub Sim: Tang Band W8-740P

                    Alright so I played around a bit more and came up with something that is maybe a bit better, the response is similar but port velocity is under 250 ms now. Its a 0.86cuF box with a 2.5x 22" port so the port will need some elbow joints but I think it should fit. Thoughts on this one?

                    Comment


                    • #11
                      Re: My First Sub Sim: Tang Band W8-740P

                      Originally posted by Operandi View Post
                      Alright so I played around a bit more and came up with something that is maybe a bit better, the response is similar but port velocity is under 250 ms now. Its a 0.86cuF box with a 2.5x 22" port so the port will need some elbow joints but I think it should fit. Thoughts on this one?

                      The only issue I see, that has been talked about in the other thread is that the sensitivity is a bit low on that woofer, not sure how loud your buddy plans on playing his music/movies but I'd like to see a bit more headroom than that if it were mine.
                      ----------------------------------
                      Gear:
                      Samsung PN50A650
                      Yamaha RX-V2500
                      Hafler DH-200
                      AC130MKII/BG NEO3PDR Two-Ways
                      RS390HF-4 w/ HPSA500

                      Comment


                      • #12
                        Re: My First Sub Sim: Tang Band W8-740P

                        Originally posted by Operandi View Post
                        Alright so I played around a bit more and came up with something that is maybe a bit better, the response is similar but port velocity is under 250 ms now. Its a 0.86cuF box with a 2.5x 22" port so the port will need some elbow joints but I think it should fit. Thoughts on this one?

                        Take a look at putting it in 0.55 cf, with a 2.4" x 13" vent. You can get 2-1/2" PVC "electrical conduit" (they just don't make 2.5" plumbing drain pipe) at Lowe's or maybe Home Depot. Don't make the sub a cube, make it 16" on the long dim. and work the other 2 out to get .55 cf. I've built several like this.

                        Comment


                        • #13
                          Re: My First Sub Sim: Tang Band W8-740P

                          First off, my apologies Operandi for suggesting you do what you've already been doing.

                          Second, can I assume that your box simulator includes a LP filter for the sub? That would explain your lack of sensitivity as the max driver output occurs at several hundred Hertz in Unibox. I'm seeing a minima at ~55Hz with your parameters that's missing in yours.

                          Chris, when I run the numbers you suggest, I get a 45Hz tuning and a 4+dB peak at 55 Hz. I need a 20-30" port before I get a shape I like. Is it just a difference in taste, or are we modeling different things?

                          HAve fun,
                          Frank

                          Comment


                          • #14
                            Re: My First Sub Sim: Tang Band W8-740P

                            Justin - thank you for that...food for thought.
                            'Soupy'

                            Comment


                            • #15
                              Re: My First Sub Sim: Tang Band W8-740P

                              if your not set on ported you might consider this guy's suggestion. though as you might notice in that thread he does get a bit of flack for using a driver shaping circuit.

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