a few questions by a DIY newb

[mexicanzero]

i recently got a 3-way 12 inch speaker and crossover designed for me by a small but reliable store in my area and i got to a few roadblocks so i thot i'd ask around... first of all should i put teh crossover in the speaker cabinet or is it better to leave it out? i;ve seen many pics of higher end audio having it out and i just think it looks cool and on the plus side if my dads soldering ends up being not so good its an easy fix... then thers the wood i was told to use 1 inch thick mdf... but thers no such thing in my city so i opted for 3/4 of an inch... is that not enough? i was also wondering bout the insulation... on the design he put 1 inch thick fiberglass insulation but the thinnest i can get is 2.5 inches thick... is ther a better substitute or should i just use that? and last but not least... should i use silicone to seal the edges of the box? or is glue and screws enough? and what bout between the drivers and the cabinet?
any other random tips would be great too...
thanx a looad
-Alex

 

[stevdart]

1. The crossover can go inside the cabinet but you should design it so that it is easily removable. Look at commercial offerings and you will see that the crossover can usually be taken out of the box by removing a few screws.

2. Do your own soldering.

3. 3/4" is fine.

4. Use polyfill stuffing instead of fiberglass. You can buy it at any crafts shop as it is commonly used to stuff Teddy Bears and such. If your design is vented, glue it onto the insides of the baffles...or if it's sealed just stuff it. From 1/2 to 1 lb per cubic foot.

5. Glue and caulk. The caulk can be either silicone or acrylic, your choice on which to use. I recommend Gorilla glue as it is actually more like epoxy than wood glue. It works with water...spread the glue on one side and spritz water on the other. Keeps you from having to fill screw indents.

6. Use speaker sealing foam tape to seal the driver to the cabinet.

 

[Ryan_Lilly]

I you have not used MDF before, you should know that you must use a countersink before you screw your peices together, otherwise the screw heads will not be flush and when you try to screw them in further the threads will strip your hole.

Test your crossover before yo seal it up in the box.

If you are willing to spend a few more bucks, I would also install your speakers using tee-nuts and machine screws, that way if you ever need to replace the driver or get to the crossover you dont have to worry about The MDF falling apart from putting screws in and out to many times.

 

[majorloser]

Somebody beat me to this, use T-nut for the 12 inch drivers. They're cheap. Also, you might want to consider thicker MDF for the front face where the 12" woofer will be mounted. You can glue two sheets of the 3/4" together. The bigger the hole, the weaker the edges.

 

[sploo]

If you are cutting MDF with powertools I'd strongly recommend at least a reasonable dust mask - preferably one that's rated for MDF.

Even better, cut it outside - as unless you've got some really good dust extraction, you'll just be blowing fine dust through the filters of your vac (and back into the room). But still wear a dust mask!

Believe me, MDF dust is nasty stuff.

 

[mexicanzero]

hah ya i learnt the hard way bout the dust mask... thanks for all the tips guys the speakers are comin along!! both crossovers done and one cabinet almost done... sadly i'm gona have to wait a few weeks to finish them since im leaving!!! arg i'm so impatient... but once theyre done i'l post pics to see wut u guys think...
thanks again
-Alex

 

[sploo]

Alex,

Look forward to seeing the pics; hope they go together OK.