Triticum Agricolam Posted November 28, 2015 Report Share Posted November 28, 2015 I don't know what to tell you about the error, but for the Sd of your sub you can use 500 sq cm. That's a pretty common value for 12" subs and should be within a couple percent of what it really is. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
DLHgn Posted November 28, 2015 Author Report Share Posted November 28, 2015 Ok cool. I will try to re-download the program and see if that helps. Link to comment Share on other sites More sharing options...
DLHgn Posted November 28, 2015 Author Report Share Posted November 28, 2015 I've tried reinstalling it and it didn't help :/ Link to comment Share on other sites More sharing options...
DLHgn Posted November 28, 2015 Author Report Share Posted November 28, 2015 Trying to tinker with some parameters. Maybe I made a silly mistake Link to comment Share on other sites More sharing options...
DLHgn Posted November 28, 2015 Author Report Share Posted November 28, 2015 Got it working. Really like it now that it's not giving me grey hairs. Also, would this be the "ideal" rounded corners of a port? If I could accomplish this, should I? Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted November 29, 2015 Report Share Posted November 29, 2015 Glad to hear you got WinISD figured out. From an airflow perspective, how you have the port corners in your Sketchup screenshot would be ideal. However those are going to be really tricky to make, and really aren't worth the effort. As long as you have your 45 pieces in there properly, you will be fine, anything more extravagant than those is really just going to be a lot of extra work for no measurable gain. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
DLHgn Posted November 29, 2015 Author Report Share Posted November 29, 2015 I figured as much....but it sure would look nice! And make me feel all proud of it. We'll see. If I can figure out a decent way of doing it, I probably will just so I can say I did. Also, after playing with WinISD, it keeps telling me that my port should be like 51" long Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted November 29, 2015 Report Share Posted November 29, 2015 WinISD doesn't properly calculate the length of slot ports. It only has limited options for accounting for end correction, none of which are appropriate for a 3 common wall slot port like you are going to be using. Because of this it tells you to make the port longer than it really needs to be. I use a spreadsheet with more sophisticated formulas to determine slot port length. The length I gave you should put you very close, if not right on, 26 hz. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
DLHgn Posted December 1, 2015 Author Report Share Posted December 1, 2015 Ok awesome. I didn't doubt you, I figured you knew what you were talking about I was just wondering if I had done something wrong. Where did you find these more sophisticated equations for calculating slot port length? That way, in the future, I don't have to rely on other people to calculate things for me. Not trying to sound ungrateful because I really am, I just don't like having to ask people to do things for me when I can do it myself. Don't want to seem lazy. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted December 1, 2015 Report Share Posted December 1, 2015 No prob man, I'm happy to share what I know. Its nice to have someone, like yourself, who actually wants to know the the "how" and the "why" and not just the "what". So I use two different equations for port calculations, they both give similar, but not identical results. The first is from JL audio's site: http://www.jlaudio.com/header/Support/Tutorials/Enclosure+Ports/Tutorial%3A+Enclosure+Ports/287541 The second is from DIYsubwoofers.org: http://www.diysubwoofers.org/misc/portcal.htm The thing I do differently, and why WinISD will lead you astray, is I change the end correction value. In the second formula end correction is the value "k". Its important because slot ports behave like they are longer than they actually are due to the sides of the box being in close proximity to the end of the port. The JL formula includes end correction as well, its the ".823" value, you can change it to be whatever you like. Here are what the values for "k" should be depending on the style of port: Both flanged 0.850 One flanged 0.732 Both free 0.614 One common wall slot 1.230 Two common wall slot 1.728 Three common wall slot 2.227 I have all the formulas put into a spreadsheet so they are quick and easy to use. It has worked well for me. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
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