Instructables

Step 3: Designing the Box: Part 2: Dimentions

Picture of Designing the Box: Part 2: Dimentions
side view final.jpg
top view final.jpg
Speaker Enclosure Diagram final.jpg
After approximating the box volume, we can then figure out its dimensions. Carefully considering the sizes of my woofer and tweeter, i came up with the following dimensions for the box:

10.0" across X 10.0" deep X 16.0" high = 1600 cubic in or 0.926 cubic ft

This is an over estimation because the walls of the box have thickness. Ideally the box should be slightly larger, but for my situation, i am not trying to make the most perfect sounding speakers, but the most convenient. Its close enough to 1 cubic feet for me.

I have drawn up some diagrams that show dimensions of the boxes that will be constructed. They are a bit small when viewing them in instructable's photo viewer so here are links directly to the jpg images.

Front View ............................... Side View ............................... Top View ............................... Complete View

Either click to zoom or Press ctrl and scroll up or down with the mouse to zoom in or out (this shortcut is very useful in many other apps too) It may be a good idea to open them up in a new tab/window for easier viewing (right click -> open in new tab)

My diagrams were made using adobe illustrator which worked like a charm. I recommend drawing diagrams like these for your speakers because it helps to clarify exactly what pieces (sides) you need and how big each needs to be.

In my case there will be 4 different sizes:
1) The front piece: .......................... 10.0" X 16.0"
2) The back piece: ......................... 8.50" X 14.5"
3) The top and bottom pieces: .... 10.0" X 9.25"
4) The two side pieces: ................ 9.25" X 14.5"

0.75" thick particle board will be used for all pieces. We are now ready to go out and buy some particle board. (Make sure to get a piece big enough to be cut up into all the smaller pieces)

In the next step we will cut each side to its corresponding dimensions and route the holes.
 
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lutkeveld7 months ago
Correct size would be 4766 cubic inch for indoor tuning. It also should be crossed way lower, around 500hz concering the woofer. The tweeter wouldn't handle that so you had no other choice. Poor driver choice, but a very nice first attempt anyhow! I wouldn't have done better when I started out. Keep up the good work :)
billbob (author)  lutkeveld7 months ago
Hi There, thanks for the comment. Seems like you have somewhat of a background in speaker building. If I may ask a few questions: How did you come up with a precise 4766in^3? Will adding more dampening material will allow you to have a smaller enclosure? Also wondering if you could explain why would it be better to crossover at 500hz. From the datasheet it looks as if the frequency response is decent up to 2-2.5khz.
lutkeveld billbob7 months ago
I calculated the values with WinISD. If you want to learn more about speakerbuilding that program is a must. On paper it performs up to 2khz, but there is a big difference between theory and practice. The calculated response based on the Thiele/Small parameters drops after 500hz. The tweeter won't take over however, so there will be a gap in the response. The woofer you linked goes much deeper, but is a bit less efficient.
billbob (author)  lutkeveld7 months ago
Also, I recently built another pair of speakers using:
http://www.parts-express.com/dayton-audio-rs180-4-7-reference-woofer-4-ohm--295-374
and
http://www.parts-express.com/vifa-bc25tg15-04-1-silk-dome-tweeter--264-1040.
and built a second order Linkwitz–Riley crossover at 1600hz. Can I ask your opinion on these? Thanks
Mr. walrus2 years ago
i would imagine using mdf for speakers, and not particle board
http://www.diyaudioandvideo.com/FAQ/Build/