Closed Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 17

Reload Thread: 1/4 Wave TL Advantages/Disadvantages

  1. #1
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.



    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    1/4 Wave TL Advantages/Disadvantages

    I'm doing some research and wanted to know what the advantages and disadvantages of a 1/4 wave TL box are... and what they have over a ported box.

    Lets use an example of 2 15" MAW-15 subwoofers on 600 watts in a 6 cube net TL or a 6 cube net ported box for this...



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com




  2. #2
    Join Date
    Mar 2007
    Location
    Bakersfield, CA
    Age
    24
    Posts
    3,353
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    disadvantage : space



    2x SAZ-1500 for SALE 310+ship ea
    RE MT 18" w/ juggaurnaut recone For Sale 320+ shipping


    Dakota Work Log


    References
    Bought From: IonSQL, PhatTonyDeMarco, nikosbuddy, spudracer326, RoLLaxPhile, hessdawg, JonMR2turbo, GohillaAudio, BushJ311
    Sold To: saturnspl1991, gbz007, SVT RELAMPAGO(3x Box Build),alex5897, David187, bland

  3. #3
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.

    Threadstarter


    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Quote Originally Posted by twisztdauthorit View Post
    disadvantage : space
    True enough, but lets leave space out of this

    I am contemplating building a 1/4 wave and I have 52" depth x 37" width x 40" height to work with.



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com

  4. #4
    Join Date
    Mar 2007
    Location
    Bakersfield, CA
    Age
    24
    Posts
    3,353
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    efficiency



    2x SAZ-1500 for SALE 310+ship ea
    RE MT 18" w/ juggaurnaut recone For Sale 320+ shipping


    Dakota Work Log


    References
    Bought From: IonSQL, PhatTonyDeMarco, nikosbuddy, spudracer326, RoLLaxPhile, hessdawg, JonMR2turbo, GohillaAudio, BushJ311
    Sold To: saturnspl1991, gbz007, SVT RELAMPAGO(3x Box Build),alex5897, David187, bland

  5. #5
    xtremebassjunky's Avatar
    xtremebassjunky is offline Is it ever loud enough?



    Join Date
    Apr 2006
    Location
    Charleston, SC, (Oklahoma)
    Posts
    3,858
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    hmmm....



    -Head Unit: Alpine-9886
    -Front Stage: 1 set of: DDA-W6.5's, DDA-W5.2's, and 3 sets of DD-T28's
    -Amps: 2x DDc4a's and 1x DD-C2b
    -Subs: 4x DD-3515E powered by 2x DD M4 -- giving me over 10kwrms... 154+ @ 24 Hz
    -Alternator: Stock 130a + 2 x 260a @ 15v Ohio Gen
    -Batteries: Batcap 3000 in front & 8400 + 4000 in back
    Refs: Alan Dante, Thilo Stompler, Nomad40, 2000LaDe, xplicitACTS, sundownz, djman37, Hoss, SPL140.2, bmxbikes, casper97ta, SkatinBassPLaya, Bibby, SeanDub, hazardous0388, Trunk_Monsta
    Team Outcast

  6. #6
    hempy's Avatar
    hempy is offline bass wiener



    Join Date
    Nov 2006
    Location
    nola
    Age
    28
    Posts
    700
    Post Thanks / Like
    Images
    1
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    I know very little about the design, but I am pretty sure you're not going to fit a TL (even 1/4 wave) for 2 15" woofers in 6 cubes.




  7. #7
    dragnix's Avatar
    dragnix is offline LXIX



    Join Date
    Dec 2006
    Location
    Socal cuz i'm So cool
    Posts
    19,628
    Post Thanks / Like
    Mentioned
    21 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    they're not designed to get loud




  8. #8
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.

    Threadstarter


    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Quote Originally Posted by hempy View Post
    I know very little about the design, but I am pretty sure you're not going to fit a TL (even 1/4 wave) for 2 15" woofers in 6 cubes.
    Net doesn't account for port area or subwoofer displacement.



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com

  9. #9
    BrianChia's Avatar
    BrianChia is offline CarAudio.com Elite



    Join Date
    May 2007
    Location
    Knoxville/Nashville TN
    Posts
    1,292
    Post Thanks / Like
    Images
    1
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Quote Originally Posted by iDesignBoxes View Post
    Net doesn't account for port area or subwoofer displacement.
    Port area and subwoofer displacement are irrelevant here. There is no "box volume" and there is no "port". Two 15's just aren't going to work in the space given.




  10. #10
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.

    Threadstarter


    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Given that I have 52" depth x 37" width x 40" height to work with, what are the advantages of a properly built 1/4 wave TL opposed to a ported box of 6 cubes with the same drivers and same power?



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com

  11. #11
    BrianChia's Avatar
    BrianChia is offline CarAudio.com Elite



    Join Date
    May 2007
    Location
    Knoxville/Nashville TN
    Posts
    1,292
    Post Thanks / Like
    Images
    1
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    The driver will behave similarly to a free air or IB setup, but the rear wave of the driver is reversed in order to bring it back in phase and help extend the low end. Because there is no actual "enclosure," instead just a wave/phase guide, it will sound "clean" like a good IB or free air setup because you don't have the complex system of enclosure reflections or port resonances conflicting with the driver output. The sound is characteristic of a true IB setup, but rolloff behaves closer to a 2nd order system whereas a free driver or IB is a 1st order system. The rolloff is thus similar to that of a sealed box but typically with much lower extension.

    Given your dimensions, you might get away with using 1 15", but I still doubt it. You'd have to calculate a correctly designed line length/taper/folding pattern to know for sure.




  12. #12
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.

    Threadstarter


    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages



    Bingo.

    I think it's right... It's my first attempt.

    I needed 10.8654 feet of port length... which is 130.3848 inches. I was able to come up with 130.4375 inches.

    I needed 234.453469 square inches of port area. 11 7/16 x 20 1/2 = 234.46875.
    Last edited by iDesignBoxes; 03-25-2008 at 06:24 AM.



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com

  13. #13
    Immacomputer's Avatar
    Immacomputer is offline Cloud disappear



    Join Date
    Sep 2006
    Location
    Ocala/Oviedo, FL
    Age
    30
    Posts
    4,670
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Transmission line enclosures are not correctly designed by taking the Sd and Fs of the driver and making them your line length and cross sectional area. It will work but it won't really be optimal.

    T-lines are not always more efficient than ported or bandpass systems and many times they transfer gain for bandwidth.

    The sound is just like Brian described as the driver can sound very natural and the roll off is much more shallow than compared to ported enclosures. The electrical impedance also should stay pretty flat and the natural peak around resonance should either be lowered or about the same as the nominal frequency. The extra air mass in the line will act like a mass on the drivers and it will substantially lower the resonance point of the system.

    For instance, my AV12 has an Fs of 24hz and 76in^2 of cone area. I designed a line with only a 35hz line length and only 42in^2 of port. The sound is phenomenal but efficiency is much worse than the ported enclosure I had that was 2.2 cubes tuned to 32hz. I had to greatly increase the gain to get respectable output but when I did, I got a very smooth response that got very low and blended with my front speakers effortlessly. It sounded much better than the sealed enclosure I had it in and could get much lower.

    This is the measured response I got in car at low volumes (high volumes not possible due to using only a 100wrms amp):



    Above 60hz, I'm out of the main boost from the transfer function. With the mids playing, the response is boosted and is pretty **** flat. I don't have those measurements on my PC though.



    Video 1
    I may make you feel but I can't make you think.
    Your sperm's in the gutter -- your love's in the sink.
    Video 2

  14. #14
    iDesignBoxes's Avatar
    iDesignBoxes is offline This many.

    Threadstarter


    Join Date
    Mar 2008
    Location
    USA
    Posts
    453
    Post Thanks / Like
    Mentioned
    0 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Quote Originally Posted by Immacomputer View Post
    Transmission line enclosures are not correctly designed by taking the Sd and Fs of the driver and making them your line length and cross sectional area. It will work but it won't really be optimal.

    T-lines are not always more efficient than ported or bandpass systems and many times they transfer gain for bandwidth.

    The sound is just like Brian described as the driver can sound very natural and the roll off is much more shallow than compared to ported enclosures. The electrical impedance also should stay pretty flat and the natural peak around resonance should either be lowered or about the same as the nominal frequency. The extra air mass in the line will act like a mass on the drivers and it will substantially lower the resonance point of the system.

    For instance, my AV12 has an Fs of 24hz and 76in^2 of cone area. I designed a line with only a 35hz line length and only 42in^2 of port. The sound is phenomenal but efficiency is much worse than the ported enclosure I had that was 2.2 cubes tuned to 32hz. I had to greatly increase the gain to get respectable output but when I did, I got a very smooth response that got very low and blended with my front speakers effortlessly. It sounded much better than the sealed enclosure I had it in and could get much lower.

    This is the measured response I got in car at low volumes (high volumes not possible due to using only a 100wrms amp):

    Above 60hz, I'm out of the main boost from the transfer function. With the mids playing, the response is boosted and is pretty **** flat. I don't have those measurements on my PC though.
    Now, after reading this, I am a bit skeptical about going with the TL.

    This guy makes them seem like the perfect box and this was one of the reasons I had originally decided on going with a TL.

    http://www.stevemeadedesigns.com/boa...showtopic=1828

    Decisions, decisions...



    Shelby... I love you...!




    880PRS Seas Neo Alums Dayton RS-180 2x MAW-15 (SOON) eD Nine.5

    AIM: iDesignBoxes
    E-Mail: iDesignBoxes@gmail.com

  15. #15
    dragnix's Avatar
    dragnix is offline LXIX



    Join Date
    Dec 2006
    Location
    Socal cuz i'm So cool
    Posts
    19,628
    Post Thanks / Like
    Mentioned
    21 Post(s)

    Re: 1/4 Wave TL Advantages/Disadvantages

    Quote Originally Posted by iDesignBoxes View Post
    Now, after reading this, I am a bit skeptical about going with the TL.

    This guy makes them seem like the perfect box and this was one of the reasons I had originally decided on going with a TL.

    http://www.stevemeadedesigns.com/boa...showtopic=1828

    Decisions, decisions...
    I believe it has been proven that what that guy says holds little validity and in fact his design of his TL box is flawed.

    What i heard




Closed Thread
Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may post attachments
  • You may edit your posts

1e2 Forum