Blog Forums DIY Speakers and Subwoofers First Build – Enclosure Type?

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    • #24932
      nixem
      Participant

      Hey guys,

      I am about to start my first from scratch build (non-kit). I am looking at a two-way tower, hoping to put a Peerless XT25TG30-04 in a Seos waveguide with RS225P-4A as the woofer. I am not sure if it will work, but wanted to go ahead and give it a try since I have the parts. It will be an active build using sigma studio, I may make a separate thread for that part of it.

      What enclosure type would you suggest? I am debating on ported vs a TL type enclosure. Either way would like to have the slot face the front if possible. I think a TL would be neat, but it seems like quite a learning curve. Open to suggestions!

      Thanks!

    • #24933
      tvor-ceasar
      Moderator

      Actually, transmission line mostly boils down to driver size and Fs/Fo, depending on what the manufacturer uses. The beauty of TL over vented/ported is the roll-off. TL is much, MUCH more gentle of a rolloff than ported. The drawback is that you need to incorporate the length of the tl into the overall box size vs. using a port.

      I’m not at home atm, but can give you an idea of what to expect for box sizes and port/tl cross-section size and length when I get back. (Man, I really need to get my quick evaluation software done and out to you guys n gals for just such a situation)

      If you do a search on here for Transmission Line Software, you’ll find a thread with a wayback machine link to HornResp software. This, along with WinISD can help you figure out the best way to go with that particular driver.


    • #24937
      tvor-ceasar
      Moderator

      A quick rundown of the designs:

      TL
      Main Box Vol 0.94 CuFt
      Line X-Section Area 50.27 SqIn
      Line Length 2.69′
      Weight of damping material (inside line) .47 lbs
      Tuned to 37.7 Hz with an approximate 6dB roll off

      (This is based on a constant area line X-Section. You can make it more like a horn by using the center point of the line as a pivot and squishing one end a bit while expanding the other end the same amount. I’ve seen designs where either end is the output, depending on if they want more velocity (smaller) or more acoustic coupling (larger).)

      Ported
      Box Vol 1.5 CuFt
      Box, Port and F3 37.8 Hz (unusual, but it is a function of Qts)
      3″ port 6-2/3″ long

      Like I said above, this is just a starting point to give you and idea of how you might want to proceed. The next step would be to go ahead and use WinISD and HornResp, and definitely read up on sites like https://transmissionlinespeakers.com/en/articles/ to get a better grasp on your idea.


      • #24979
        nixem
        Participant

        Would you recommend hornresp or spicyTL?

      • #25033
        Elliott
        Participant

        I use SpicyTL, biggest upside of SpicyTL over hornresp is that you can model lining the enclosure with fibre/open cell foam, and you have more control over the rate of expansion. I can help you with that if need be, tbh I need to remake/update my SpicyTL video, it wasn’t the clearest and I missed a couple of details. I love that you’re considering a transmission line, really, it’s possible to make one for any kind of driver, you just have to change how you do it, for example a driver usually more suited to a sealed enclosure can be used in a mass loaded transmission line (tapers from large to small surface area). IMO, a transmission line is a better modelled port. Typical port simulations don’t consider resonances in much detail, not the position of the driver relative to the box walls, not the port start to the centre of the driver. SpicyTL does, that’s why I like it so. Ported speakers are easier, that’s their upside, but in the case of everything else, transmission lines can be better in every way except size. In terms of everything else, the only thing with better phase properties and below tuning frequency control is sealed. If the driver is suited, MLTLs will give you tuning well below tuning frequency too which I find very neat.


        Elliott Dyson – Elliott Designs (YouTube) – 3rd year MENG Student
      • #25035
        Elliott
        Participant

        Hi Charlie, whilst these numbers are true of a generic transmission line, they are rarely built this way since it is usually more suitable to make them tapered such as in an MLTL, which also changes the properties of a TL, usually why it’s best to model, but it’s true a ported box is usually more efficient, but at the expense of mid-bass and midrange resonances, which are particularly important in a two way build like this.


        Elliott Dyson – Elliott Designs (YouTube) – 3rd year MENG Student
      • #25037
        tvor-ceasar
        Moderator

        Yes, these are generic calcs just to give you a rough idea, mostly of total enclosure size to see if they’ll fit within the aesthetic design goals. Do you want a small-ish box, or will something a bit larger be acceptable. Of course, if you had a very large driver with a very low Fo or Fs, the x-section could be massive with a very, very long length, therefore, the resultant box could be huge. Would that be acceptable or just completely out of the question? So, just an idea of what you’d be looking at.

        BTW, catch you tomorrow in the chats?


      • #25038
        Elliott
        Participant

        Hopefully, but probably not, got an early start in the morning 😕


        Elliott Dyson – Elliott Designs (YouTube) – 3rd year MENG Student
    • #24985
      tvor-ceasar
      Moderator

      I haven’t used either, but I believe someone on here has used Hornresp. SpicyTL is a new one on me. If you try one out, let us know what you think of.its ease of use, etc.


      • #25034
        Elliott
        Participant

        Hornresp is easier to install, SpicyTL is easier to visualise what’s happening once installed, but both are about as easy as each other to set up the model, just different. SpicyTL also has a couple more capabilities than hornresp.


        Elliott Dyson – Elliott Designs (YouTube) – 3rd year MENG Student
    • #25036
      Elliott
      Participant

      I’ll give it a run in the SIM this week if you’d like. I’d just need the max width, depth and height for the enclosure (including panels) thickness of panels/material. For height, disregard the portion with the tweeter so I know what I’m working with in terms of space for the woofer 😉. I’d love to make a video on it if you’re up for it, if I could get a couple of photos off you of the end result/build? Anyways, that last part is just an idea. 👍


      Elliott Dyson – Elliott Designs (YouTube) – 3rd year MENG Student

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