Tempest Design help

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  • rudee
    Member
    • Oct 2000
    • 37

    Tempest Design help

    Hey all-
    I need a little help- I've preordered my tempest driver and picked up my sonotube/mdf yesterday to start the project. I've been reading many, many post concerning the build of this beast and I only seem to get more confused on the math/dimensional end- I'm ok on the assembly end of building the perfect beast- I have the 24" tube (We had to cut it into ~ 6' sections to get it home) This will be used for HT only as I have a MKv90 to use on the music end of my setup. My room is about 25x25x8. Power will either be the 250w sub amp from Adire or I have a Yamaha M60 that can push about 400w @ 4ohms. Size is not important as the wifey doesn't care or knows that my obsession with HT cannot be cured so why fight it. :-)
    I would like to go as low as possible with what I have to work with.
    Would I would love to know is.....
    1-How tall? I have about 65-70" per section of tube.
    2-Port(s) size? Length, diameter + flares?
    3-Batting? How much? Should I line the inside?
    4-Bottom firing and bottom port(s)

    Sorry for all the questions. I hope I included enough info on my end to paint the picture of performance I'm looking to get out of the Tempest. I really like the forum here. I've been a lurker at HTT for a long time and really appreciate all the insight that comes from knowledge and experience you all have to share.
    Mucho Thanks in advance if anyone can help me get started.

    rudee
  • Andrew Pratt
    Moderator Emeritus
    • Aug 2000
    • 16507

    #2
    Welcome to the forum rudee, you'll find that there isn't really a perfect design, you can tune a little higher or a little lower depending on your tastes. Since size isn't much of a concern I'd go for something in the 8 - 10 cubic foot range and tune it to 16hz. Use either a single large port on the top endcap (8 or 10" vent) or go for several smaller ports on the bottom. I didn't want to have ports on the top of mine so I opted for three 4" ports on the bottom but its up to you. If you want to see my sub click on the link below to my HT site then goto SonoSub




    Comment

    • rudee
      Member
      • Oct 2000
      • 37

      #3
      Andrew,
      Thanks for your reply- I have "studied" your technique many times. It looks great I can only imagine the performance.
      I have done my homework on the construction- (Thanks for the pics (Patrick Sun) What I'm not sure of are dimensinal aspects of the design. So if I go the 10 cube ft . Were talking 24" x 60" tube- I'd rather do the bottom ports also- How do I calculate the port length and number of ports to get the correct tuning- I'd like to get the magic 16 as advise by Dan.
      Thanks again
      rudee

      Comment

      • rudee
        Member
        • Oct 2000
        • 37

        #4
        "ronbo" #1

        Comment

        • rudee
          Member
          • Oct 2000
          • 37

          #5
          "ronbo" #2

          Comment

          • rudee
            Member
            • Oct 2000
            • 37

            #6
            opps- wow- the submit button REALLY works.....
            rudee

            Comment

            • Patrick Sun
              Super Senior Member
              • Aug 2000
              • 1380

              #7
              Rudy, it sounds like you want to build something like Sunosub II. That's a link from the HTT (I can't find the HTG version that that thread) that I created and it should help you in building your sonosub. Once I get the driver, I'll finish up the rest of Sunosub II.




              PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs
              PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs

              Comment

              • rudee
                Member
                • Oct 2000
                • 37

                #8
                Thanks Patrick
                I didn't realize sunosub II was 24". That's the ticket- If i remember 14" hole is what the Tempest will need-correct? I'll run through your very detailed post again- appreciate the thorough documented assembly- I really need to dl the software and spec this stuff but I loath the thought of it- Hate the math- love to build.
                Any word on a shipping date?

                THANKS A BUNCH!!!!!
                rudee

                Comment

                • ThomasW
                  Moderator Emeritus
                  • Aug 2000
                  • 10934

                  #9
                  Rudee

                  Here are some plots of different tunings, I posted for Jeremy Santos and his 24" tube



                  Tempest shipping date is supposed to be 10/18/00. The MKII Shiva is already shipping. We received some yesterday.

                  Don't worry about flares for 8" or larger ports. These if needed, must be custom fabricated. Some people are using large funnels cut to fit.

                  A good material for 10" (recommmended) ports is just more sonatube. If you use this size port, in a 24" tube, the woofer will need to be at one end, and the port at the other

                  I'd suggest lining the inside walls of the tube with insulation. Start with 3-1/2" thick fiberglass without any backing if you can stand working with "glass". Otherwise go to a fabric store and get "bonded" polyester batting. Don't get "loose" fill poly, it's too hard to work with.




                  theAudioWorx
                  Klone-Audio

                  IB subwoofer FAQ page


                  "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                  Comment

                  • rudee
                    Member
                    • Oct 2000
                    • 37

                    #10
                    Thanks also Thomas
                    I'll have to go with the Single Tempest 10.29 cu ft, Fb16Hz F3 22.44Hz 3-4" ports 33.35" design- I'm limited to size due to the fact of splitting that 12' monster in half- man- my Trooper was "filled to the gills".
                    Are these calculations right? 10.29 cu ft= 24"x61.75" internal (not including endcaps)
                    Any recommmendations on a different port configs for this set-up? (2) 8" ports 25" 0R (1) 10" port 40"
                    I don't have any objections to a top port (?) Can it be cover with a metal speaker grill or something of sorts? Were talking purely asthetics now- if this interferes with funtion or causes port noise then "forget about it"

                    Oh yeah-I'll pass on a tip-
                    I purchased a great circle jig from my local Lowes (I looked EVERYWHERE)
                    It's really nice- comparable to the JasperAudio Jigs but cheaper and easily available. It's made by Vermont American and called the Lewin Circle Cutter-cuts circles 8-48" ( Patrick- for SUNOSUB IIII?)adaptable for most routers- cost here was $29.99. Perfect circles here I come

                    ThomasW thanks for the help-

                    Now- on to my black coffee and sawdust!!!!

                    rudee

                    Comment

                    • ThomasW
                      Moderator Emeritus
                      • Aug 2000
                      • 10934

                      #11
                      Hi

                      Sorry but a tube 24"X61.75" internal height is, 16.17 cu ft

                      pi times radius squared, times height, divided by # of cu inches in a cubic ft

                      3.1417 X 144 X 61.75 divided by 1728= 16.17

                      If you have this height use one of the 16 cu ft tunings on the website. Remember + or - 10% is Ok with these numbers

                      A 24" tube 39" internal height is 10.2 cu ft

                      2-8" ports will flow more air than a single 10 so use those. Also they can be shorter so port resonances aren't an issue.

                      Sure a grill to cover the port outlet is not problem.

                      Since you're probably already building it. If you check back to this thread and see the numbers, don't worry. We can tune it for max performance with whatever you ended up building. Just give me the final numbers for what you built and I'll run a new design.




                      theAudioWorx
                      Klone-Audio

                      IB subwoofer FAQ page


                      "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                      Comment

                      • rudee
                        Member
                        • Oct 2000
                        • 37

                        #12
                        aaaahhhhh haaaa- It's that pi thingy (duh) I didn't include in my initial calculations- I wasn't fibbin' about the math part! I haven't cut anything as of yet so I'm still good for using the Single Tempest, 16.6 cu ft tube Fb 16Hz, F3 19.26Hz, one 10" diameter port 36.52" design you sent earlier- Bigger is better right? hold on let me ask my wife- yep! she confirmed it go BIG! This is good- thanks again for the correction
                        I'd rather use the one big port anyway-

                        rudee

                        Comment

                        • ThomasW
                          Moderator Emeritus
                          • Aug 2000
                          • 10934

                          #13
                          Look at the last plot on the my webpage. That's probably the best one to use. It's slightly flatter in the mid-bass.

                          Either one will work




                          theAudioWorx
                          Klone-Audio

                          IB subwoofer FAQ page


                          "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                          Comment

                          • rudee
                            Member
                            • Oct 2000
                            • 37

                            #14
                            Thomas,
                            Here's what I'm going to have in the end:
                            Total internal height- 59.5"
                            Port diameter 11.25"

                            Can you run these numbers and see if I can get close to optimal tuning?

                            Thanks,
                            rudee

                            Comment

                            • rudee
                              Member
                              • Oct 2000
                              • 37

                              #15
                              ronbo #3

                              Comment

                              • rudee
                                Member
                                • Oct 2000
                                • 37

                                #16
                                ronbo #4

                                Comment

                                • ThomasW
                                  Moderator Emeritus
                                  • Aug 2000
                                  • 10934

                                  #17
                                  Rudee

                                  Just hit the "submit" key ONCE. The server almost always gets the message on the first submit. But sometimes it's slow posting the message and returning you to the thread.

                                  Tube internal height 59.5"= 15.58 cu ft gross. This can't use an 11.25" port because the port needs to be 58.03" long for a tuning of Fb 18Hz and 102" long for a tuning of Fb 16Hz

                                  For something a little more "reasonable" use Fb 18 Hz, same internal height 59.5, then use a 10" diameter port 32.55" long. Line the internal walls with damping material 1.5" thick




                                  theAudioWorx
                                  Klone-Audio

                                  IB subwoofer FAQ page


                                  "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                                  Comment

                                  • rudee
                                    Member
                                    • Oct 2000
                                    • 37

                                    #18
                                    Thomas,
                                    What if I use the other section of 24" tube I have and get an internal length of say 64.0- reason being, I've already cut my top cap port-and would like to use the cap. Lowes had 12" or 8" concrete tubes so I bought the large which turned out to be 11.25" Will the added length help? Just a thought? Ok -hit the button once- got it
                                    rudee

                                    Comment

                                    • Patrick Sun
                                      Super Senior Member
                                      • Aug 2000
                                      • 1380

                                      #19
                                      Rudee, always finalize the design before cutting anything!




                                      PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs
                                      PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs

                                      Comment

                                      • rudee
                                        Member
                                        • Oct 2000
                                        • 37

                                        #20
                                        Good advice to heed Pat!- Live to learn-Learn to live! Not too much of a biggie- I do have more MDF and can obtain a 10" tube if need be, but it would be nice to use the cap I already have- I could do a "stove pipe" type port to obtain the need length? anyone know if this changes the effect of the port? Up telescope!!!!!! har har
                                        rudee

                                        Comment

                                        • Patrick Sun
                                          Super Senior Member
                                          • Aug 2000
                                          • 1380

                                          #21
                                          Rudee, you can extend the port outside the sonotube/endcap, so periscope away!




                                          PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs
                                          PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs

                                          Comment

                                          • rudee
                                            Member
                                            • Oct 2000
                                            • 37

                                            #22
                                            periscope not telescope- what was I thinkin'? I'm figuring the total tube length including endcaps to be ~62.5". If I do the 11.25x58.03 for a 18hz tuned port with ~6" "stoved piped" out the top that leaves about a 10" clearance above the driver. Is this adequate? If this works ok I figure I can do something cool on top to conceal/accentuate the port.
                                            Hey miscalculations aren't so bad- just takes a little imagination which I have plenty to spare- Graphic design is my day job-
                                            Thomas/Pat what do you think about the clearance?

                                            rudee

                                            Comment

                                            • ThomasW
                                              Moderator Emeritus
                                              • Aug 2000
                                              • 10934

                                              #23
                                              Yes Rudee the port can stick out of the top of the sub, no problems except for looks Also sonatube tends to get banged up if not "protected"


                                              But if you want to use the port already have,(meaning 11.25" diameter), use a 40.6" long. and put all of it inside the tube. This will give you a "tuning" of Fb20Hz.

                                              I doubt that you will be able to "hear" any difference between the Fb 16Hz and Fb 20 Hz. The plots will look a little different, but the real world performance will be almost identical.




                                              theAudioWorx
                                              Klone-Audio

                                              IB subwoofer FAQ page


                                              "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                                              Comment

                                              • rudee
                                                Member
                                                • Oct 2000
                                                • 37

                                                #24
                                                Thanks Thomas & Patrick
                                                I often wondering about the differences or if it was about "splitting Hairs" I'm sure it's not but for this time 20Hz will be fine.
                                                Just when I was about to get fun & funky on the exterior port-like an elephant trunk with big Dumbo ears- oh well (sorry kids)

                                                Thanks for doing the modeling. I'll get into the innards of that next time for "ru-dee-sub II"
                                                I'm sure I'll have a question or two when I get this beast fired up and dialed in. I'm looking to complete constrution this weekend and wait on the driver.

                                                rudee

                                                Comment

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