How to design a subwoofer with winISD and fusion 360

[@naehh73]

Sincerely, thank you Sir. Awesome stuff, keep it up!

[@MethodicalMaker]

Thanks! i appreciate the words of encouragement!

[@michaelrobinson9643]

Remember to add extra to panels with an external exposed edge so you can trim them back perfectly once glued together. This is a common technique that is used to achieve perfect interface for butt joints. Don't do it for mitre joints though :P.

[@droper683]

Great vid I understand the info. Why use SPL instead of Transfer function Magnitude? Is Fusion free?

[@MethodicalMaker]

SPL gives you the estimated real world output, where transfer function magnitude shows you the effect the box has compared to an infinite baffle setup (basically having an infinitely large wall the sub is mounted to). fusion is free for personal use with some restrictions. if they get in the way, you can apply for a startup license. they seem more on the lax side of granting licenses, though there is an approval process so its not instant.

[@droper683]

@@MethodicalMaker Thanks really appreciate the answers

[@audfrknaveen2256]

Is it really 30m/sec or 17m/sec ??? For a rectangular slot port with very little rounding of edges (5 mm radius edges)

[@MethodicalMaker]

Are you talking about the examples in this video? Port velocity was ~30m/sec for those... the next graph (where it said cone excursion at the top) was for the travel distance of the speaker cone its self.

[@audfrknaveen2256]

@@MethodicalMaker well... I always kept port air velocity under 17m/sec. I never went upto 30m/sec. So I am not sure if we get port noise with 30m/sec. Did you build subs with 30m/sec?? did you notice port noise ?? (With very little rounding of edges)

[@MethodicalMaker]

@@audfrknaveen2256 Yeah, I built the box shown by the green line. I could not hear any port noise. the edges were rounded with a 1/2" round over on the outside of the port, and internally i believe it was rounded on both edges with 1/4" round overs, and then smoothed with some light sanding.

[@RobHTech]

--IDK that it is worth my time to use Fusion 360 to design a "Box" because I don't plan on making enclosures all the time. Besides, I can draw up the box with pencil and paper; otherwise, I just design in my head and build off that. I used to build houses, and reading blue prints so much that I can picture them in my head, but also can modify them in my head to the new concept. --But it is pretty cool to see your design in a CAD program. --The winISD part of the vid was good. --Plus, I'm not building a square/rectangle box, anyway. The left side will be concave, 8" tall, 14" long, then 5.5" long at different angle, etc. Does that program, Fusion 360, work for something like that? --Or does anyone know of a program that can use the iPhone, etc. to measure the volume by taking a picture?

[@MethodicalMaker]

The most useful part for fusion 360 is calculating volume. Sure, you can design on paper or in your head, but the volume calculation becomes complex when thinking about bracing, internal subwoofer displacement, and subtracting port volume. Fusion 360 can do very complex shapes, and theres tons of videos out there for learning how to do this. the iphone can build 3d models, if you have one with the depth sensor(don't use the apple ecosystem, so could be wrong... but i think the 12 max has this, as well as one of the ipads) then you can build models with that, and they should be very high quality. If you don't have one that supports that, then you can use a technique called photogametry to generate 3d objects with a bunch of photos. You get the best results if you keep your phone steady and rotate the object on a lazy susan. There are apps to do this as well as cloud solutions. Once you have the object, you just scale it off of a reference value then calculate the volume in a cad program.