ATTN: ThomasW twin tower clone help

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  • JaysonY
    Junior Member
    • Dec 2000
    • 7

    ATTN: ThomasW twin tower clone help

    I've built a single tower modeled after these but am using a AVA250 for power. The only dvd handy @ hookup was Toy Story 2 and on the opening TS2 logo and Buzz fly in the tempest driver is FLAPPING badly. I,ve checked for leaks, plugged port and driver hole and filled tube w/compressed air, there are no leaks. What am I missing?
    The receiver (outlaw 1050) sub out level is set @ -10db and the volume Knob on the AVA250 is @ 50%.Please Help!!
  • ThomasW
    Moderator Emeritus
    • Aug 2000
    • 10934

    #2
    Hi

    First what do you mean flapping?. If it's pumping appropriately to the signal being sent then no problem. If the driver is "unloading" then raise the tuning, or use a subsonic filter.

    If you can hear noise being made (flapping?)that's not part of the soundtrack then there are only a few things that can cause it.

    1)EQ in the amp (if being used) is overdriving the amp even at low output settings.
    2)Port tuning isn't correct, might try raising the tuning
    3)Defective woofer
    4)Defective amp

    There is quite a bit of subsonic info in TS2

    What are the SPL levels when this is occuring?
    How big is the room?




    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

    • JaysonY
      Junior Member
      • Dec 2000
      • 7

      #3
      The flapping seems to me like the woofer is bottoming out this is not part of the soundtrack!my klipsch ksw12 has no problems with this material with all the settings set the same.

      1)EQ in the amp (if being used) is overdriving the amp even at low output settings.

      Not using any thing but stock Adire AVA250 fed from the sub out on the Outlaw.

      2)Port tuning isn't correct, might try raising the tuning

      Had thought this could be the problem, but wanted to get as much info as possible before making any changes to the port length.


      3)Defective woofer
      4)Defective amp

      There is quite a bit of subsonic info in TS2

      What are the SPL levels when this is occuring?
      How big is the room?

      This is happening @ about 90db on average during these scene's per Rat shack meter from listening position 11ft from the sub.

      The room is 23ft long 12 ft wide w/8ft ceilings and the sub is corner loaded along the front 12ft wall.

      Jayson

      Comment

      • ThomasW
        Moderator Emeritus
        • Aug 2000
        • 10934

        #4
        Please give me a better description of what you mean when you say "flapping". Is this a fluttering noise like the blades of a fan makes? Or is it a mechanical rubbing sound?

        Sub shouldn't be bottoming with 90db output levels. If a driver is bottoming there is a mechanical could like metal hitting metal scraping sound.

        I believe there is EQ built-in the Adire amp. It can beturned off or atleast turned down.

        Is it only occuring on the particular passages you mentioned? Or is it occuring at 90db with other source material? If it's only occuring with the heavy subsonics like TS2 and the like then you have 2 choices. Raise the tuning, that's why there aren't any problems with the Klipsch sub it can't even try to play that low. Or use a subsonic filter.

        Also do you have access to a higher powered amp?

        The design for the "Twin Towers" was based on using a BIG amp. And since the "twin Towers" have 2 woofers so they are automatically 3+db more efficient.

        Also please give me the actual specs for the sub. Diameter and inside height of tube, diameter and length of port. I'll compare it to the model I have for the twin towers.




        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

        • JaysonY
          Junior Member
          • Dec 2000
          • 7

          #5
          The flapping sound is like fan blades hitting air but VERY LOUD!!
          the sub specs are;
          24" dia tube
          internal height of 62"
          10" dia port 35.6" long
          tempest driver wired in parrallel
          AVA250 amp

          I've tried the sub with Super Speedway also with the same results. I'll have another amp to try this friday(QSC 1400 200watts @ 8ohm 300w@ 4ohm).

          Were working on another sub with 24" dia tube x 48" internal hieght, tempest driver, 8" dia port 35" long powered by the QSC amp. This will be for myself. Sure hope I have better luck with it!

          Comment

          • ThomasW
            Moderator Emeritus
            • Aug 2000
            • 10934

            #6
            Ok well you did copy Jeremy's design to the letter. And I'm sure as you've seen from his posts there aren't any inherent design flaws.

            But please understand that Jeremy's subs were custom designed for his room, and his amp, and his listening requirements. That's why 2 tubes and 2 drivers were used. This design wasn't meant to be a "generic" design. My "generic" designs are more conservative. This design is pushing the performance envelope of the Tempests just about as far as possible for very LFE. As a result the need was for 2 complete subs to get very high output(SPL's). So it may not be possible to get the performance you desire with this specific design.

            I assume that you double checked the voice coil wiring?

            A mechanical noise is usually bottoming, but on occasion I heard what's called "hard clipping" of the amp, and that has a very mechanical sound.

            But I seriously doubt that this is occuring at 90db. If you have access to a computer with a sound card that can be plugged into your system download the NCH tone generator. Do a sine wave sweep from 100Hz down to about 15Hz. Put the RS meter as close to the woofer dust cap as possible. Use 90db as the reference point for 100Hz then keeping the volume level the same, walk down to 12Hz and record the SPL's. (WEAR EAR PLUGS)

            You can get the tone generator program here
            sound, audio, software, download, program, programs, applications, wav, record, play, recorder, player, shareware, tone, instant replay, telephone, hold, messages, action, audio action, development, software development, programming, programmer, freeware

            Scroll down toward the botton of the page you'll see a download button in the section where there's a picture of the tone generator.

            FYI, here's a little info on sound pressure levels as they relate to distance.

            Loudness decreases by 6 dB (half as loud) every time the distance from the sound source is doubled
            If you start 3 feet from the speaker and move back to 6 feet, it will sound half as loud (-6 dB)
            If you move from 6 feet to 12 feet, it will reduce in volume by half again
            So if you were measuring 90db "average" at 11-12 ft from the woofer. The woofer was actually playing 98db or so "nearfield". That's loud (permanent ear damage if not wearing ear plugs)and very likely clipping the plate amp

            Also did you apply the "corrections" for the RS meter? If not the woofer was playing even louder than that, depending on frequency. For example if measured at 20Hz the nearfield reading would be increased to about 105.5db and at 16Hz 109.5db

            Also I saw this in your post on HTF & HTT
            my xover is set to 60hz @ the receiver(outlaw 1050)and set to 180hz on the AVA250
            You only use ONE of the crossovers, either the one in the Outlaw OR the one in the sub amp. Don't use both. So set the Outlaw sub setting to NONE, then set the plate amps XO to something like 80 or 100Hz.


            Hope this helps

            Regards
            Thomas




            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

            • JaysonY
              Junior Member
              • Dec 2000
              • 7

              #7
              I can't turn off the Outlaws xover to my knowledge with out shutting down the sub completely. I did make an adjustment to the AVA250 xover It's now set @ about 100hz and the receiver is still @ 60hz. the receiver out is still @ -10db but theAVA250 volume is now @ 1/3%.

              I did a similiar test to what was suggested, no output on sound card for direct connection to system, using Avia GTHT. Set the spl level @ 90db with 100hz signal and let disc play. The sub spl output was
              100hz-80hz 90db
              80hz-60hz 100db
              60hz-45hz 106db
              45hz-30hz 108db
              30hz-25hz 98db
              25hz-20hz 93db

              these were taken about 1-3" from the dust cap and are uncorrected #'s for the RS meter(can't find my correction value cheat sheet wife cleaned the desk!!)
              I know this is not the correct way to do a test but was the only thing I could come up with @ the moment. Will try to down load something and burn a copy later!!

              Could the plate amp be clipping with TS2? I'm home alone this morning and was able to try Gladitor,and Twister after making the adjustments to the xover and volume control no problems with them even @ very high levels, was getting 126db from the sub @ edge of tube near the floor during The Battle Of Cartage(Gladitor) and 1960 Prologue(Twister) and 110 db from setting area. TS2 still had some trouble but not nearly as bad as before.

              Maybe I'm expecting to much with TS2.

              Comment

              • ThomasW
                Moderator Emeritus
                • Aug 2000
                • 10934

                #8
                Yep I'm pretty sure you're running the amp into "hard" clipping. Also probably asking a single Tempest to do too much as well. Only testing with a more powerful amp will tell which of these problems it is, if not both.

                You're getting 110db-126db on "regular" material the amp is going to be unable to pass the subsonic transients that TS2 and other DVD's have. Only true monster subs with BIG amps can reproduce high SPL subsonics.

                Since you're posting over on HTF. Do a search for posts by Bob Sorel in the DIY-Advanced Hardware section. There's a monster thread where Bob, Greg Monfort, your's truly, and many, many others try to diagnose a virtually identical problem with Bob's Tempest sub. Turned out he was simply expecting too much from a single 15".

                If you friend wants/needs more output from this existing tube, rebuild the end caps and add a second Tempest.

                For recordings that have major subsonics; "The Haunting", "Titan AE", "TS2", etc, either turn down the sub or use a subsonic filter.




                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

                • JaysonY
                  Junior Member
                  • Dec 2000
                  • 7

                  #9
                  Thank you Thomas for all the help. Sure hope the other sub with 24" dia tube x 48" internal hieght, tempest driver, 8" dia port 35" long powered by the QSC amp @ 200watts per VC works out. Do you have any suggestions before its final assembly is completed?

                  Thanks agian,
                  Jayson

                  Comment

                  • JaysonY
                    Junior Member
                    • Dec 2000
                    • 7

                    #10
                    Do a search for posts by Bob Sorel in the DIY-Advanced Hardware section.

                    Can not find the thread under Bob Sorel

                    Comment

                    • ThomasW
                      Moderator Emeritus
                      • Aug 2000
                      • 10934

                      #11
                      Well looks like HTF wiped the files off their server. The thread was last fall. BobSorel was having problems similiar to you. Turned out he was running 110db alot of the time. Dan Wiggens said that single Tempests aren't designed for that type of "use/abuse". That thread is what led to the "deal" with HE15 and the passive radiators that Stryke offered.

                      BTW my understanding is that Stryke is going to offer the same "deal" again sometime in early summer. If you find it interesting remember that that sub will play "anything" at almost any SPL BUT it must be driven by a HUGE amp (1000 watts or so)

                      I've ordered the components to build 2 of the HE15 cubes. My drivers and PR's are supposed to be shipped by the end of next week. I'll post info about the boxes as time permits.

                      Your 48" inch design loooks fine. Be sure to line it with 2" or so of polyester batting. And remember that Adire drivers are very good but they aren't designed for 110+db as a regular diet for a single driver




                      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

                      • JaysonY
                        Junior Member
                        • Dec 2000
                        • 7

                        #12
                        Thanks Thomas, you've been a great help!!
                        The sub will likely rarely see 110db during normal listning. But every once in awhile a guy likes to show off a bit. My buddy seems pretty satisfied with the tower clone he's never had a sub in his system at all!! Should be a real eye poping experience once we get it to his apartment this friday!

                        Now how about the subsonic filter? What does it do? I'm not familiar with one. Where can they be purchased?

                        Jayson

                        Comment

                        • ThomasW
                          Moderator Emeritus
                          • Aug 2000
                          • 10934

                          #13
                          Good subsonic filters (aka high pass filters) are expensive/somewhat complicated. The easiest way to get one is find an EQ, active XO, power amp or some other device you need that has one built in.




                          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

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