First sub project almost done...questions

[leonard b]

I am building my first sub, a 142.5 L Shiva, with the 250 watt amp from Parts Express and the FP-4 flared port kit. I figured if I can't afford an SVS, I should build the closest thing to it that I could afford. I used the plans from the Adire website, because a lot of the formulas for calculating tuning, etc. are over my head. I just wanted a plan that I could build. My box is built and my amp has arrived today and I just need to cut out a hole for it. My questions are in regards polyfill. I have seen information on the web saying that I shouldn't add polyfill to adding 4lbs of polyfill. Does anyone have any advice?
Also, should I use ABS glue to assemble the port kit?
Finally, my calculations were just a tiny bit off and I have a little bit of the side brace occupying the space where the shiva will drop into. Any ideas for a good tool to cut out a bit of the mdf without causing damage to the brace ie. splitting? Since this is my first project I really want this to turn out well and avoid anything that will degrade how the sub turns out. Thanks

[JonMarsh]

For the case of the 142 liter EBS alignment, you will probably want to use some stuffing, at least lining the walls of the enclosure, especially if you use a high crossover point (85-100 Hz), because then there is more driver interaction with the box in frequency ranges in which standing waves can form. The other side is that depending on the system location in room, having near flat anechoic response to 18 Hz may result in in the perception of too heavy a bottm end, or more HT oriented than music oriented. Using the poly fill, at least behind the driver, may help that. Polyfill will tend to dampen upper bass/midrange, but doesn't in my experience have a lot of influence on the low bass, as long as you don't go crazy with it.

Actaully, my preference for internal cabinet damping is Owens Corning Miraflex; it's not itchy, easy to handle, and works well midrange through bass.

Miraflex

At their web site you can use their locater to find local dealers.

Best regards,

Jon

[David R.]

Using ABS glue on the port work yes. Thats what i used.. You need to be carefull or else the glue will end up getting spread/squeezed onto the inside surface.. Not the prettyest to look at.

Polyurethane glue is another one that will work well.

As for cutting out that brace.. Kind of depends on how much access you have to it.. Can you get in there with a jig saw? If not a dremel with a cut off wheel might be your only choice. You will need to buy a lot of cut off wheels though.

[leonard b]

Thanks for the reply. The part that needs to be cut is easily accessible. I think that I can get access to a dremel. I have to be careful and take off only what is necessary.