I currently have 2 15 fi Q's and want to put them into a fiberglass enclosure. I will frame the back, bottom, and both sides out of MDF, but i am wanting the top and front of the enclosure to be fiberglass. What is the recommended thickness or number of layers of mat or cloth that i should apply for 2 Q 15's. Amp using the AQ 2200D amp if that helps. Thanks

With the front of the enclosure, are you doing anything else in the boot to integrate the shape of the front?

Generally for a combination of the Q15s and a 2200w amp, I wouldn't recommend using fibreglass as part of the box due to the potential of flex of the front.

If you are integrating the front with the rest of the boot, I'd recommend a cover panel with the shape you want and making the front out of wood. That way you know the box is solid and you have a cover panel that is shaped and contoured the way you want.

If you were to fibreglass the front, then you'd want it to be around the same thickness as the rest of the box.

Fibreglass will flex too much if too thin, putting stress on the baskets of the subs, unless the fibreglass is the same thickness as the rest of the enclsoure as well as bracing. Because it is that thick, then the installation becomes a higher cost as well. Fibreglass also has a higher resonance than wood, espec when thin so that is also an issue.

I've chucked together a diagram to show how I would approach the situation of having an aesthetic cover panel on the front:

As you can see, the main box is constructed with a couple of mdf rings to raise the height of the subwoofers. Then a aesthetic cover panel is constructed in the contoured shape that is attached with some brackets on the sides. Its rough but its an easy concept to grasp.

Hope that helps

DC