Fiberglass vs. Wood

Wood (MDF) is much easier to work with. But as far as the sound goes, there is no real difference ( as long as the boxes are built correctly). Fiberglass is much harder to work with but the end result can be spectacular.

I like making glass boxes, but it does take time. So if your in a hurry forget it. Also there is a little bit of a learning curve, but again the end result is an awesome looking box

 

if all the subs are wired together to one channel then no, they dont need a splitter.

as far as needing a port..... the boxes you saw must have been sealed then.

ive seen a few sealed and ported. mdf and glass. when someone builds a glass box its for looks mostly.( in the ones ive seen) or to fit multiple subs on the face of a box.

they will and mostly do sound the same if built correctly.

 

was it wired wrong? or were the two on different amps?

im sure you may be confusing a splitter with a brace. if not, i think some people might separate the chambers if they have 2 diff amps running multiple subs.

if one were to stop working it wouldnt affect the other sub. hope that helped.

i dont think i mentioned this, but all my subs are in one large enclosure with some bracing. this keeps the box from vibrating a little.

now if i ever went to two diff amps to power 2 subs each i might think about a new box to seperate the 2 pairs.

 

They were wired incorrectly.

Two woofers in a box, with no divider, act as one. They do not work against each other.

Properties for two woofers in a single enclosure (from the Loud Speaker Design Cookbook by Vance Dickenson ISBN 0-9624191-7-6 Oct 1991)

E. Sensitivity will increase +3 dB for a parellel connection and decrease -3dB for a series connection when compared to the single woofer
F. Cone excursion will be half that of a single woofer enclosure.

I only included the last two properties listed because these apply. For the last two properties to be true the woofers have to work together. If the box is divided, there is no sensitivity increase. Also excursion would not decrease.

 

say u have 2 subs that are 4 ohm SVC, to make a 2 ohm load you wire them parallel. all the positives together. now, say u wired one sub the opposite. in this case off the positive terminal on the amp to the positive of one sub and the negative of the other then the same for the negative. this means the subs are 180 degrees out of phase. basically when one sub hits out, the other will hit in causeing cancellation.

sorry, that may be hard to follow.

 

In my opinion the divider is not needed. I have found that larger enclosures perform better. When we divide a box, what we have are two small enclosures and smaller enclosures are a little peaky and they don't get as low as a larger box. Also there is no relative gain.

When we put two or more (not more than 3 or 4) woofers in the appropriate sized single enclosure, we get relative gain (its louder), it plays across a wider frequency range (it hits lower), and its smoother.