Home Forums DIY Speakers and Subwoofers I could use some advice…

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  • #25174

    Rich
    Participant

    I was watching a Toids DIY Audio YouTube video tutorial on the proper way to input the T-S parameters in winisd. After entering the required fields for my own subwoofer build I noticed that I was getting outrageously high numbers for port air velocity. And, no matter what I did, no matter what adjustments I made, the problem persisted. Thanks to Toids’ videos I learned that these high port air velocity numbers meant that I would get significant chuffing from the speaker port. After posting my question onto the YouTube comment board, Mr. Toids (no disrespect, I just don’t know his real name) suggested that I post some screenshots in the forum and get input from the community. So, here ya go. If you good folks could help me resolve this chuffing problem, I would most certainly appreciate it.

    Just so you know, the box is 4 cubic feet, tuned to 20Hz, and the HP filter is set at 20Hz. And, it’s not two different speakers. I just have the same speaker twice (superimposed) so that I can you y’all more speaker stuff.

    • This discussion was modified 1 week ago by  Rich.
    • This discussion was modified 1 week ago by  Rich.
  • I could use some advice…

    123toid updated 1 day ago 3 Members · 13 Replies
  • 123toid

    Administrator
    June 23, 2022 at 3:04 pm

    @Rich glad to have you on board. I think we can definitely help you with this. It looks like the port that you have right now is only about two and a half inches. That’s going to be too small. The typical Port size is going to be between 1/3 to one half the size of the driver. Obviously most people aren’t going to want to put a 6-in port on a 12-in driver. So I would recommend trying a slot port. Maybe something about 12″ wide x 1.5″ and see how long it is. Also pay attention to the first Port resonance. Do you have any idea of where you want to cross this over at? Typically you want your first Port resonance to be twice wherever you cross it over at. So if you’re subble for only place 80 hertz and below, you’d want a first Port resonance of 160 HZ or higher. We’ll see where we are when we get some results from that. But I think that would be closer to what you’re going to be looking for.


    I could use some advice…

  • Rich

    Member
    June 24, 2022 at 11:25 am

    Hi 123toid,

    Thank you for your reply. I went ahead and did what you suggested. I changed the port from round to slotted. Even after making the port 2″ X 12″, winisd calculated that my port would have to be 42″ long to maintain the tuning while bringing the port air velocity under 30ft/sec. Did I buy the wrong driver? Or, is there something else I’m doing wrong, or forgetting to do? Again, thank you very much for your help. I appreciate it.

    • This reply was modified 5 days, 14 hours ago by  Rich.
  • tvor-ceasar

    Moderator
    June 24, 2022 at 6:39 pm

    I think I may have found it.

    Set BL to tm instead of N/A. Always check your units.

    So, I put the driver in, gave it a 4 Ft^3 At 20 Hz box, 20 Hz highpass (2nd order Butterworth), and put in 400W:
    14″x1.5″x36.5″ long port puts you at 16 M/S and you’ll just be exceeding XMax. That’s at ~380W (full XMax).


  • 123toid

    Administrator
    June 24, 2022 at 11:19 pm

    @tvor-ceasar I completely agree. I just got back from vacation so I haven’t been able to run the numbers, but it does appear that the data in WinISD is off. When I did check this driver earlier, I was getting some similar results to yours.

    @Rich try to re input the driver data because I think you put it in incorrectly. If I get a chance to tomorrow I’ll send you over my driver data so you can load it. Maybe you can see where the differences lie within the data so that you can correct your file.


  • Rich

    Member
    June 25, 2022 at 2:54 pm

    First off, I really appreciate both of you taking the time to help me with my problem. I’m grateful.

    I cleared the fields and re-entered all of the values according to the Dayton spec sheet (not the Parts Express specs) and triple checked my units. Nothing changed. The port air velocity is still ridiculous. Plus, I watched more tutorials on winisd to make sure I wasn’t missing anything. But, I think I’m still missing something. Again, this has got to be user error. Here’s the spec sheet for the subwoofer.

    • tvor-ceasar

      Moderator
      June 25, 2022 at 8:16 pm

      I just double checked my inputs.

      Here’s my screenshot. May we see an updated screenshot of yours?


    • tvor-ceasar

      Moderator
      June 25, 2022 at 8:21 pm

      Here’s my driver file. Just change the extension to wpr


  • Rich

    Member
    June 27, 2022 at 10:37 am

    Hi Tvor-Ceasar,

    I really appreciate you being involved in my nightmare. Please be advised, I am a technology moron. So, the only thing I really noticed was that you numbers (and maybe your units?) were different than mine. Beyond that, I’m clueless. I cleared all of my entries for the driver, then entered your numbers into the appropriate fields in the proper units. All I got was error messages. So, I did the only thing I know how to do and re-entered the numbers from the Dayton spec sheet. Nothing works no matter what I do. What will it cost me to have you figure this out for me? I’m lost and crawling around in the weeds.

    Also, I cannot seem to paste any more pictures to the forum. Maybe there’s a limit? I have NO idea. Thank you for your time, Sir.

    • tvor-ceasar

      Moderator
      June 27, 2022 at 1:23 pm

      I’m not aware of any limitation. @123toid do you have any idea why?

      I believe you are only inputting the numbers in Green, all else is auto-calculated. If you are doing that and the units are correct, then it SHOULD work. If that doesn’t work, download my driver file above (the .txt file) and change its extension to .wpr and move it to where your other driver files are located. You can then go into the driver editor and check the units to make sure the units are correct. Reference my last screen cap above.

      I’ll be back later.


  • Rich

    Member
    June 27, 2022 at 10:40 am

    Hi Tvor-Ceasar,

    I really appreciate you being involved in my nightmare. Please be advised, I am a technology moron. So, the only thing I really noticed was that you numbers (and maybe your units?) were different than mine. Beyond that, I’m clueless. I cleared all of my entries for the driver, then entered your numbers into the appropriate fields in the proper units. All I got was error messages. So, I did the only thing I know how to do and re-entered the numbers from the Dayton spec sheet. Nothing works no matter what I do. What will it cost me to have you figure this out for me? I’m lost and crawling around in the weeds.

    BTW, I cannot seem to paste more pics to this thread. There’s a limit maybe? I have no idea. Thank you very much for your time, Sir.

  • Rich

    Member
    June 27, 2022 at 6:10 pm

    Remember when I said that I was a technology moron? Well, now I can prove it. I just discovered that I had my rear port air velocity set to feet/sec. So, I was seeing numbers like 60 to 70 feet/sec. I watched Toids ported speaker tutorial probably 10 times. Then, by the 10th time, I finally caught the missing piece of the puzzle. He said, “You you should try to keep your port air velocity at or below 17 METERS/SECOND. For Christ sake! See? Moron!

    I’m really sorry for dragging everyone through this. But, at least I now know that my speaker will work. I wanna thank Toids and Tvor-ceasar for being amazing moderators and awesome people.

    • tvor-ceasar

      Moderator
      June 28, 2022 at 12:13 am

      @Rich I have a confession: I saw that. I didn’t mention that because, as the son of a teacher, and having teaching going way back in my lineage, I recognized your dogged determination to master what’s in front of you. If I had told you outright, I doubt it would stick as well as it will since you’ve found it yourself. And you did find it, so a moron “you ain’t.” (Love the 3 Stooges)

      Congratulations and welcome to the next step. Onward and upward!


    • 123toid

      Administrator
      June 29, 2022 at 2:08 am

      @Rich Glad you got it figured out! We would love to see pictures of the build as you build it. Would you be willing to create a build log? P.S. in order to add more pictures, just click the button that looks like a camera underneath the text box (the box you are typing in). It should allow you to upload photos.