View Full Version : Intricate Plan? Will it work?

01-18-2007, 01:47 PM
I am planning to do a box that I have never seen before.

This is still being planned, but my physics proffesor came up with the idea.
Initially, I came up with the idea to put regular egg cartons inside of the box, but she said that has been done already, so she suggested to put half circle soft rubber balls (about 28) to absorb and deflect sound everywhere in Chamber 1. In Chamber 2, the plan is to put a row of "reflectors" to push the sound back and forth, thus filtering the sound equally into four "deflectors" that are to push the sound back into the reflectors until it reaches Chamber 3, in which there in no interference.. It might seem crazy, but coming from a woman majoring in physics, I think she has the right idea. Even more importantly, this will count on my finals for the class. It will not be so much scientific, but my class will listen to one enclosure using the approximate measurements with no modifications and the enclosure I am making (also with the same dimensions, minus modifications), all with the same subwoofer.

Here's the very very rough draft

If you think it will work or has any ideas on how to make it better, reply to this post.

01-18-2007, 01:50 PM
that is done alot with pro- recording speakers it basicly eliminates the resonance that occurs inside the box and makes it have a very flat response curve

The fin looking things in the port will greatly affect how the air travels out and I believe it will greatly affect how smoothly the air will flow out of the box

01-18-2007, 02:13 PM
You're doing a lot of things that will possibly affect the tuning frequency of the enclosure. The rubber balls will probably help with rear wave upper order harmonics and possibly make the sound a little smoother. The fins will probably lower the tuning frequency and add turbulence and possibly noticeable port noise. Also, if chamber 2 is not the same width as chamber 3, you will have a very restricted port and chamber 2 will act mostly as the port length and I'm not sure what affects you will see from chamber 3.

This is all speculation though. Build it and find the actual tuning frequency and then see how far off the enclosure would theoretically be.

01-18-2007, 08:33 PM
I talked to her again, and she said to make the reflectors .25 inches apart and every eight or so, add another .5 inches. Again, theoretically, by spacing them out, the sound waves will hit resistance, and it ought to create more bass throughout the enclosure. Also, I will be using 3/4 red oak and coat the interior with either a few layers of foil or try and mold a thin plate of tin. God, I am in way
over my head, but it will be a great achievement if succesfully completed.
I have been getting alot of help for this project, and when I start it next week, I will post a ton of photos for it. Again, if anyone has any ideas, help me out. Though I am required to post any names in my report who helps out, I don't need to nescassarily if you do not want to.

Thank You

01-18-2007, 09:59 PM
Here are my two suggestions:

1) Make sure that the maximum width of chamber 2 is equal to the maximum width of chamber 3.
2) Make two controlled enclosures. Have one built with the same interior dimensions and port dimensions. Have the other built to specs with the actual tuning you get from your enclosure. Make sure to have the same port area and net enclosure volume though.

That way, if the tuning is pretty far off from the similar enclosure, you can know if you're hearing a difference in tuning or your obstructions.

01-19-2007, 11:11 AM
Can't wait for some pics.

01-19-2007, 11:26 AM
For this to be usefull you really need to make 2 versions, one with all the mods and the other with identical dimentions sans mods (your control), then measure frequency and amplitude response of both.

01-19-2007, 01:37 PM
For this to be usefull you really need to make 2 versions, one with all the mods and the other with identical dimentions sans mods (your control), then measure frequency and amplitude response of both.

3 versions and that was already mentioned by me and the original poster. ;)