I need someone to test out a theory for me
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Gold Member Username: InsearchofbassPost Number: 2669 Registered: Jun-04 | i was wondering if it was possible to use some type of resistive material in a port to achieve a lower tuning than would normally be seen for a said length of port tubing. I think I saw this somewhere but im not positive if im remembering right |
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Gold Member Username: InsearchofbassPost Number: 2670 Registered: Jun-04 | i no this will create more resistance in a port which would make port volocity higher but i have ideas to counter that effect |
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Gold Member Username: InsearchofbassPost Number: 2671 Registered: Jun-04 | the first reason i wanted to use this approach for was so that box volumes could be smaller and port lengths could be shorter and yet achieve low port tunes |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 665 Registered: Nov-04 | Exactly how do you mean? would you cover the inside surface of the port with something. |
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Gold Member Username: InsearchofbassPost Number: 2674 Registered: Jun-04 | along the lines of the aperiodic design with a thin layer of fiberfill or something inside the port |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 666 Registered: Nov-04 | you lost me... |
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Gold Member Username: InsearchofbassPost Number: 2675 Registered: Jun-04 | what i mean is you would put a thin layer of insulation inside the port and run test tones assuming you know where the port was tuned to before the experiment and see if the port tune would lower as i expect it would |
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Gold Member Username: InsearchofbassPost Number: 2676 Registered: Jun-04 | i theorize this because the airflow would change fooling the port just like it fools a enclosure |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 668 Registered: Nov-04 | What would it be like it you used like sandpaper? |
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Gold Member Username: InsearchofbassPost Number: 2677 Registered: Jun-04 | no you want airflow just restricted amounts of it |
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Gold Member Username: InsearchofbassPost Number: 2678 Registered: Jun-04 | you dont want to make the port opening smaller you just want to slow the air down traveling through it |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 669 Registered: Nov-04 | Are talking just about the inside wall of the port so just the inside surface of the port is covered or generally the whole port so you cant see inside the box? |
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Gold Member Username: InsearchofbassPost Number: 2679 Registered: Jun-04 | the inside walls maybe right at the edge of the exit of the port but as i sit here i expect how far forward or backward you go in the port with this idea would give some intresting changes id bet |
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Gold Member Username: InsearchofbassPost Number: 2680 Registered: Jun-04 | because the timing of the reactions would change (intresting thought) |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 670 Registered: Nov-04 | Have you ever thought of a port with a slightly smaller port inside of it that can be adjusted in and out to be able to quickly change the tunging of the port and then when you have it tuned the way you want it you can lock it in position. |
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Gold Member Username: InsearchofbassPost Number: 2681 Registered: Jun-04 | yes i had that idea too a while back and ive actually seen those for sale at my local car stereo shop a few years ago |
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Gold Member Username: InsearchofbassPost Number: 2682 Registered: Jun-04 | im looking at my idea from another angle tho (the one im sharing) |
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Gold Member Username: InsearchofbassPost Number: 2683 Registered: Jun-04 | i had this idea like 20 mins before i saw jons reply about port tunes to trevor lol....but because of his explanation to trevor now i have a better understanding of application of my idea here |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 671 Registered: Nov-04 | Wouldnt that be somewhat the same thing? Your not exactly fooling the port this way but it is varibly-tunable. |
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Gold Member Username: InsearchofbassPost Number: 2684 Registered: Jun-04 | my goal is to do away with long port lengths and i think i also stumbled on a way to taylor sq in a different way as well |
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Gold Member Username: InsearchofbassPost Number: 2685 Registered: Jun-04 | imagine this a resistive type vent persay with no port length but its ported ...this is one idea besides the varied depths inside and actual port tube playing with timing issues |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 672 Registered: Nov-04 | How would this be done? How is this possible, every one has different opinions on what they like and what they don't. |
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Gold Member Username: InsearchofbassPost Number: 2686 Registered: Jun-04 | "and actual port tube" should read "an actual port tube" |
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Gold Member Username: InsearchofbassPost Number: 2687 Registered: Jun-04 | it would be based on various things but i wont go into that but i believe it can be done as i suspect it could both ways |
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Gold Member Username: InsearchofbassPost Number: 2688 Registered: Jun-04 | i dont think your really catching my concept |
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Gold Member Username: InsearchofbassPost Number: 2689 Registered: Jun-04 | it s just like any box you port it to what you think will sound best for you and your music tastes...this idea would be no different |
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Gold Member Username: InsearchofbassPost Number: 2690 Registered: Jun-04 | try it out on a simple ported box that you know where its tuned before hand and youll see the posibilities and application for these ideas |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 673 Registered: Nov-04 | Ok I got ya on that but on the whole ported with no port lenth im lost. Is it like having the air move slow in a smaller port as opposed to have the air move faster in a larger port. Since the air would be slowed down in the smaller port it would sound be tuned the same as the faster air in a larger port. |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 674 Registered: Nov-04 | disregard the word sound. |
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Gold Member Username: InsearchofbassPost Number: 2691 Registered: Jun-04 | yes thats my theory but you could slow the air down with the no port length idea by adding more resistive material ....the same could be done with the ported idea with it placed in various depths of the tubing |
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Gold Member Username: InsearchofbassPost Number: 2692 Registered: Jun-04 | various single depths resulting in different outcomes esp where timing aspects are concerned |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 675 Registered: Nov-04 | Lol what about like a powerful little fan that can be mounted to blow inside of the port? That would creat some resistence but I dont think its enough. |
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Gold Member Username: InsearchofbassPost Number: 2693 Registered: Jun-04 | i got another idea lol how bout a vent routed to the voice coil of the subwoofer from the outside of the box....higher power handling anyone? |
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Gold Member Username: InsearchofbassPost Number: 2694 Registered: Jun-04 | nahh dont think the fan idea is a good one |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 676 Registered: Nov-04 | What If you can keep like a sealed box pressurised Wit a cold gas like co2. |
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Gold Member Username: InsearchofbassPost Number: 2695 Registered: Jun-04 | not sure if that would work i do know it would have to 100% air tight tho |
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Silver Member Username: AraknidBOCA , FL U.S. Post Number: 677 Registered: Nov-04 | Well im all out of ideas, Im gonna go but maybe later someone else might have some suggestions. |
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Gold Member Username: InsearchofbassPost Number: 2696 Registered: Jun-04 | yeah same here later man |
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Gold Member Username: Jonathan_fGA USA Post Number: 4086 Registered: May-04 | Look into transmission line enclosure design, they use some form of wool to slow the air velocity down so that they don't have to use as much port length. Most sites listing also have equations that help you choose how much the density will affect the tuning. I'm not an expert on T-lines, so I can't really offer a lot of input on that one  |
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Gold Member Username: InsearchofbassPost Number: 2700 Registered: Jun-04 | yeah Jon I saw that when i ran across t-lines in my search for different box designs but i believe their focus is on using it inside the enclosure itself not the port. I think this way may have a different outcome. Im theorizing along the lines of the ap design but from a different angle. |
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Silver Member Username: AlpineuserWinchester, TN Post Number: 470 Registered: Mar-05 | sean u need to take a break before u give yourself an anurism |
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Silver Member Username: Kd7nfrMontpelier, ID United States Post Number: 108 Registered: Apr-05 | Yea bro. Just get/build a box that's tuned to a good frequency. (Hey, gotta give him credit for trying, people like him make the world a better place :P) |
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Gold Member Username: InsearchofbassPost Number: 2741 Registered: Jun-04 | lol guys ive been into this stuff on and off for like 16 years but havent gotten curious with the technical side until the last two years...Why not try ideas like these they are pretty much free to try...I like a challenge its fun to me |
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Silver Member Username: GeekbikePost Number: 156 Registered: Dec-04 | A transmission line is basically just a port without the enclosure. Read this: http://www.t-linespeakers.org/design/classic.html |
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Gold Member Username: InsearchofbassPost Number: 2756 Registered: Jun-04 | thanks knacko im still digesting that info though |
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