The ulitmate subwoofer enclosure

[4thclasspower]

Yes, As far as I understand, standing waves will cultivate mostly in sharp 90 degree corners.

[4thclasspower]

So moving forward, has anyone tried cementing a enclosure?

I've noticed that some competitors make use of plexiglass resin to further harden the walls. Out far east like those guys seem to be doing all sorts of crazy things.

yep, steel, concrete, all types of wood, plastic, fiberglass resin, granite, acrylic, and yes even tiles have been done before.

The point in any of that is for a rigid, smooth surface, but using some materials can add an unwanted resonance at certain frequencies so for SPL that can work well, but for SQ not so much.

I use the good ol fiberglass resin/sand/portland cement mixture for a solid, resonant free material.

Oh and also hexagons and octagons have also been widely used with just OK results.

Believe it or not, simple rectangles and squares have performed the best in cars, with some key angle shaping on the interior corners.

Would you be so kind as to share with us how to blend and apply this mixture?

[Goblenator]

The best box depends on the type of car you drive, your preference in sound. For me the best sounding box is a T-Line box but it requires alot of space and alot of time playing with the design. Lots of people like a regular ported box but i don't because of the limited range of frequency. It's all about what u want to get out of your sub.

[87regal]

I would like to start of with saying I have experimenting lately with speaker box designs and educating myself with acoustical engineering.

One type of enclosure that had fascinated me was the taped horn. I have completed the experiments I wanted with them, and concluded that they don't work well in the car environment.

I believe the reason you did not have any success in a vehicle may have been because your particular design was not suited to work well in a pressurized environment. Generally speaking I have noticed horns, t-lines, etc(I think these type of enclosures would be considered acoustic impedance matching transformers, rather than helmholtz resonators.) work best in open areas and cars like SUVs and Hatch backs. I have been told the cabin is like an extension of the line length.

I've noticed that a lot of people are not following some fundamental rules in acoustics, and building there enclosures in-efficiently. Example:

The worst enclosure shape to the best shape:

Square with speaker centered (maximum standing waves and speaker destruction)

Rectangle

Triangular

Egg shaped the best

Don't forget Hoffman's Iron law: Small box, low end extension, sensitivity...pick 2 Can't have your cake and eat it too lol

As far as the enclosure shapes, I wouldn't worry too much about standing waves inside enclosures. I think it was one of PWKs youtube videos that said you would need an enclosure the size of a small room before standing waves became a problem in low frequencies.

My next build will include A AQ HDC3 18

Box design: Hexagon shaped using 11 ply, .75 birch, aluminum braced, and now considering to add ceramic tiling to the interior walls.

I will be building a standard enclosure,(rectangle/square) of the same volume to test this against.

Before I finish, I would like someone(you all) to discuss, what shape, and position is best suited for a port in car audio? I've seen spl boxes with the port extending outside the enclosure, so is this the best? As far as I can remember the port should be at least half its length away from the closest wall.(don't quote me on this).

There is almost no information on the web about this stuff, and I hope this discussion can help educate me and other bass heads alike!

There is no BEST alignment. Every situation can be different. As far as the SPL boxes, that is to minimize impedance rise. Looking forward to seeing the results.