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  • Cabinet lining

    I am considering types of lining for a vented cabinet. I came across F-26 and F-26N felt, is there a difference between the two in performance?

  • #2
    I've seen acoustic fibre tiles, fiberglass, rockwool, yarn, denim, carpet padding, and most commonly that cheap waffle foam mattress topper. Tell me more about this felt you speak of.
    http://techtalk.parts-express.com/fo...khanspires-but
    http://techtalk.parts-express.com/fo...pico-neo-build
    http://techtalk.parts-express.com/fo...ensation-build

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    • #3
      The Felt Store has F-26 felt discounted right now. F-26N felt is what other audio sites sell. The N stands for needled and I don't understand the differences. I asked the felt sites but they refer to felt they sell. So I am wondering if anyone has experience which the differences and performance.

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      • #4
        I can't find anything definitive that says what the difference is between F26 and F26N. I use 1/2" carpet underlay felt in applications where inch to inch and a half thick polyester batten or open cell foam is too thick to easily fit it place. One advantage to it is that you can usually get all you want for free by dumpster diving at carpet stores.
        www.billfitzmaurice.com
        www.billfitzmaurice.info/forum

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        • #5
          Somewhere along the way, I've come across some experimenting done in regards to using damping/absorption materials where a certain type of felt was deemed best, but this was in regards to 'tuning' the diffraction/absorption of a tweeter, not the longer wavelengths of a woofer.

          I'd be curious to know what you find out.
          http://techtalk.parts-express.com/fo...khanspires-but
          http://techtalk.parts-express.com/fo...pico-neo-build
          http://techtalk.parts-express.com/fo...ensation-build

          Comment


          • #6
            Thanks Bill. Do you have to wear a helmet to dumper dive? That's a good idea about the felt underlay for carpet.

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            • #7
              https://www.monarchtextiles.com/prod...lepunched-felt

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              • #8
                Wow, thanks, that site discusses both felts types. Now which works better for lining cabinets. Last 25 years I built several sets of speakers and subs. I stayed sealed and recently TL designs, with the sealed having amps with a boost around 35 to achieve the low range. This time I felt I needed to learn about vented subwoofers and thus linings. I used Bass Box Pro and saw that my velocity was a little high so I selected to line all walls which got the velocity down.

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                • djg
                  djg commented
                  Editing a comment
                  No help with that. I use the gray foam marketed as "acoustic" or stuff with pillow fill.

              • #9
                Originally posted by alexb View Post
                Thanks Bill. Do you have to wear a helmet to dumper dive?
                The only thing you'll find in a carpet store dumpster is carpet, underlay, cardboard tubes and so forth. Where the needs of ported cabs are concerned don't lose sleep or waste money, they don't require anything special. With larger boxes I use open cell foam mattress topper from Walmart.

                I used Bass Box Pro and saw that my velocity was a little high so I selected to line all walls which got the velocity down.
                You lost me completely there. What velocity? Port? Lining the box won't affect that.
                www.billfitzmaurice.com
                www.billfitzmaurice.info/forum

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                • #10
                  Bass Box Pro indicated a port velocity of 39ms, which was undesirable. I am designing around a psp flared port. When I went into the program and chose line all walls, the result was a velocity of 33ms or 34ms which is desirable. Apparently enough back waves are absorb by the box the reduce the port velocity. Of course I am using addition padding directly behind the driver.

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                  • #11
                    I don't have Bass Box Pro, so I can't say what it's showing. I use WinISD, which has the option for changing the Qa value, which reflects absorption losses. The default value of 100 is a bare box. 50 is a fully lined box. The port velocity difference between 50 and 100 is so slight that it's barely discernible, if at all. With a value of 10, a lightly stuffed box, there's noticeable reduction in port velocity. With a value of 5, a heavily stuffed box, there's a significant reduction. But unlike sealed cabs one would seldom use enough stuffing to get a Qa of 10, let alone 5, because in so doing you also have a sensitivity loss, as the reduction in port velocity is accompanied by a reduction in port gain. As for acceptable velocity, I design to a maximum of 25m/s at the power level that reaches xmax.
                    www.billfitzmaurice.com
                    www.billfitzmaurice.info/forum

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                    • #12
                      Got me to thinking. Bass Box Pro assumes maximum power for the driver chosen, thus maximum velocity. I seldom power my system above 40%, so my resultant velocity should be significantly below my design velocity. I will have to go into program and see what differences that makes.

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                      • #13
                        Maximum thermal power is irrelevant. Maximum displacement limited power is what matters. As often as not that can be half the maximum thermal power, if not less.
                        www.billfitzmaurice.com
                        www.billfitzmaurice.info/forum

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