Material for speaker building

Gary Steele · Post by **Gary Steele** » 10 Oct 2000 11:00 pm

Has anyone ever built speakers out of MDF which is called (Medium Density Fiberboard) These places that sell all kinds of lumber say lots of folks use this. It is dense and has no voids. How do you tune a speaker box with a port in bottom all the way across? I want as small as box for a 15INch speaker as i can get but want it to sound good. But i want a closed back. Any Ideas? Thanks Gary!

Gary Steele · Post by **Gary Steele** » 11 Oct 2000 6:43 pm

Delete this no one knows any more than i do!!!

Al Marcus · Post by **Al Marcus** » 11 Oct 2000 9:06 pm

Gi Gary, I have tried all those routes and just decided to go buy a good professionally made speaker in a proper cabinet. Then you know it is right....al

Terry Downs · Post by **Terry Downs** » 11 Oct 2000 9:15 pm

MDF is an excellent material to use for speaker cabinets. Plywood has resonances associated with the glued layers. If you have the Thiele-Small parameters of the speaker, you can calculate the box size and vent dimensions. I have a spreadsheet that does this. See

http://nightshift.net/tech.htm

Select the Musician's Workbook. If you have any questions let me know.

------------------
Terry Downs
http://nightshift.net
terry@nightshift.net

<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Terry Downs on 11 October 2000 at 10:16 PM.]</p></FONT>

Bill Rowlett · Post by **Bill Rowlett** » 12 Oct 2000 10:37 am

Gary,

I've built several cabinets, both open and closed out of MDF. The only drawback is that it's heavy. The lightweight many ply spruce that most speaker companies use appears to be fine if you can find it at a lumberyard.

To use the port cut across the bottom, you have to consider it just like any other port. Use the wood thickness as the port depth and the surface area as, well, the surface area. If you want the port all the way across the box, then the port size may well dictate the box size and it is two equations and two varibles to solve for. Otherwise, just cut the port what ever size it needs to be for a larger box.

Hope this helps,

Bill

Rich Paton · Post by **Rich Paton** » 20 Oct 2000 3:46 am

Gary, what model 15" speaker will you use, and what dimensions for the box?
There's detailed & basic data for JBL musical instrument soeakers at this link, but a lot of the info would basically pertain to other models as well. http://www.jblpro.com/pub/manuals/enclgde.pdf