port size/length?

mhmacw

i built a box for a 15 inch dvc ma151xq. its 3/4 mdf 30 x18x18. i want 3 ports on the bottom. how long and how big around should they be? also how high off the ground? i have 6 inches of verticl to work with though i know it wont need all of it. also what amp is recommended? i want a plate either the bash or dayton unless there are better options. 2 or 3 hun for the amp is all i want to spend. thanks,dan

john E

it looks like you will have around 4.5cu.ft,I you use a single 4 inch port it would need to be around 9.12 inches long tuned at 25htz.,if you have braces built into your box and takeing in the volume of the woofer and bass plate ,you may not have but around 3.9cu.ft.then the one 4 inch port would need to be around 11 inches,but if you are wanting to go with three 3 inch ports then it would need to be 21.25 inches each,plus wil the smaller ports you will more then likely get port noise. .you would be better off going with one big 4 " port.IMO Bash makes some good plates ,but the daytons are not bad and they are cheaper.

mhmacw

ok... ive had some discrepencies with the port lenght and size between informants if you will haha. i have the box volume at 4.49 without reduction for speaker and stiffeners. with r3duction i went with 4 ft/3. the nomenclature for the speaker says "vented to (hz)" so im figuring thats the freq to calc to at 42 with -3db gain so 39 hz right!? i plugged that into mine and got... 1 port 4 inch i.d. 2.64 inches long. at 25 hz i got 10.64 inches or 10 5/8 i guess right. it all sound pretty close to me. my hang up is the book says 3.25 ft/3, 42 hz, (3) 4 inch ports, 12.5 long. i get 7.13 long and i know thats a big difference. any ideas?

rallyshark

You got threads going all over the place, lol! I posted a response in you "custom enclosure thread".

mhmacw

just trying to cover the bases brother!