Sealing a ported box...sort of.

[ez2hotwire 10+ year member]

I bought a prefab sealed box (I know, I know, disgusted with myself) but I will silicone along all the edges just in case it’s not completely airtight.
Anyway, I’m also going to put a piece of wood over the hole (on the inside of the box, I’m ok with the slight loss of volume) made for the terminal cap and use binding posts instead. My question is does the small square piece of wood used to cover up the hole have to be MDF or can it be a different type of wood? I don’t want to buy a big sheet of MDF when all I need is a 3” x 3” piece.

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[Jonnyswboy]

You can probably use any wood apart from maybe particle board. I had the same experience with a prefab and highly recommend just building a new box. Your sub will be way louder.

 

[RobGMN Premium Member]

Use a thick piece of wood, liquid nails, and some screws to lock it down.
If the prefab box is made well with decent wood, loudness is not a problem.

Windows closed and moderate volume, I have two prefabs that can be heard a block away. Spectrum analysis shows no additional noise added by the boxes.

 

[audiobaun 5,000+ posts]

You dont need to buy a full sheet of MDF.. H.Depot and Lowes also sell 1/2 sheets and even smaller for small projects, for like shelves ect.. I would use a min of 5/8". Plywood will work just fine. Make sure you seal all around it on the Inside as well as the outside so no air escapes. Should be just fine

 

[RobGMN Premium Member]

You dont need to buy a full sheet of MDF.. H.Depot and Lowes also sell 1/2 sheets and even smaller for small projects, for like shelves ect.. I would use a min of 5/8". Plywood will work just fine. Make sure you seal all around it on the Inside as well as the outside so no air escapes. Should be just fine

Good point. They may even give away a scrap from their cutting area big enough to cover a port hole.

 

[JakeW]

Beat me to saying it! I was also gonna seal my ported underseat prefab box, in anticipation of port noise. The volume it would then have been was too large sealed for the sub to perform properly, reducing its power handling. Truth to this? I left it ported, plenty loud for 5k!

Good point. They may even give away a scrap from their cutting area big enough to cover a port hole.

 

[SlugButter]

I’ve seen a few prefab ported boxes that were given to me after doing custom box builds for people, and some of them weren’t the most horrible things I’ve seen. Cheap for sure, but not totally unusable. I modified a really small 15 inch prefab ported box, added a double baffle, and turned it into a sealed box for a high school kid recently for his 15 and it sounded great. I would definitely add some bracing to the prefabs though, sealed or ported. Most of the prefabricated boxes I see come through have burst at the seams, even if the size and port tuning is decent for the sub.