lithium

then panels are resonating and flexing which will vibrate against other panels. which can be treated with cdl to some extent. as long as the noise is outside and not inside then who cares?

well the box design would have to account for the bracing used. im not too familiar on the best way to brace a box, but i think that would include 45's in the corner and vertical and horizontal bracing with large dowels or ripped down 2x4s. i would deff double the top layer atleast. good bracing in the box is a must. perhaps double baffle all around if you have space and no concern for weight. you would need to confirm a single 8" port is enough for the subwoofer. a single 8" port is only 50 in^2 of port. im guessing the blt has about 30mm Xmax. so 1 port is not enough. http://www.carstereo.com/help/Articles.cfm?id=31 i would just go with a slot port design to save money.

it would need to be reconed. if the price is right then perhaps consider it. if you dont want to deal with that then keep looking.

you would probably have to do some testing to figure out what frequency would work best. have your tried modeling different box's to see what frequency the box peaks at given a certain tuning? if you dont have time for testing then this would ball park it for you, i think. just throwing this out there, you could design the the box with multiple ports so you cover some up to lower the tuning (swap daily tuning and competition tuning on the fly).

LOL...The flex looks crazy. They were separate statements. 4" aero ports? i see no aero ports broham

likely nothing but worth messing with a bit. if you had strong midbass upfront then thats another story. google destructive interference

looks like regular pvc ports to me

to decrease the volume you could add 45s to the corners like Julian suggested. i think you could do this thru the sub hole. if you had spec's for the box you could calculate the effect on tuning. in other words, if i remove X amount of airspace, the tuning frequency will now be XX hertz. i would also try flipping the phase on the subwoofer. if there is no phase adjustment then just switch the + and - speaker wires at the amp.

I would suggest adding larger and larger 45's in the corners... it is a much easier way to raise tuning and is easily reversible. Simply calculate the Volume of a square and half it, you will end up with your amount of space taken away then you can calculate how much it raised your tuning. FTFY and shortening the port would raise the tuning. i like julian's idea since it is easier to add 45s then to shorten a slot port. if it was a pvc port then that would be easier.

i dont see any mention of TA either.

so your amp does not have a sub sonic filter built in? how about your headunit? if your amp or hu already has the filter then no need for and external filter. you can either shorten the length of port or decrease the volume of the box to raise tuning IIRC. you should also try moving the subwoofer enclosure around the trunk and aiming in different directions. in my car, firing into the trunklid from about 5" away resulted in the loudest/lowest response and firing forward was the worst output. this varies car to car so you may find something different that works for you. what are your other setting set at? bass boost off? any additional "loudness" setting on? what is the box specs? tuning and net volume? vehicle?

would take alot of work to get a usable subwoofer out of it. even with all the dimensions to figure out what size coil, basket, and softparts. perhaps someone out there can identify the motor and has done a build with one of them before. but this looks like a money pit to me.

lets define some terms the rest is simple math -gross volume. total volume of the box without any displacement calculated (external dimensions) -net volume. volume of the air space after subtracting port displacement, sub displacement, bracing, etc. -port displacement. volume of air occupied by the port inside the box -sub displacement. volume of air occupied by the subwoofer inside the box -port area- self explanatory -port length- hope this is too so the net volume for the sa-8 you say is .5-.75 cubes. that means that after all displacement you need .5-.75 cubes of space. i didn't go over your numbers to see where you made a mistake. google the appropriate online calculators and figure things out.

try it at 2ohm and see if that is loud enough for you. not like your going to need that much power with so much cone area.

never heard of amp being magnetized... was a subwoofer sitting on top of it?

http://en.wikipedia.org/wiki/Constructive_interference the phase dial changes the phase of the signal produced by the amplifier. so for a simple example, imagine that both your subwoofer and midrange are playing same frequency. now if the phase of the sound wave produced by the subwoofer and midrange are in phase with each other then their amplitudes add together and the result is a more output at that frequency (this is constructive interference). For the case that they phase of one speaker is out of phase with the other the result is a loss in output (destructive interference). because the subwoofer is louder then the midrange the waves do not cancel completely. your not likely to notice a difference no matter where you adjust the knob. all you can do is experiment with it.

no such thing as underpowering a subwoofer.

Anyone know a good book for learning Matlab?

1" is probably the size of the dome.. look for the cut out diameter to find the size hole you need. it should also list the other dimensions in the manual.

the 5.25s may just not play quite as low. play around with raising the sub xover up a little higher.

lets try to get a good thread going here. OP we need goals, budget, etc

The only thing is the battery is in the trunk. The hood is very confusing and I dont know exactly where my routes would go without examples/explanation. the big three in your case would be. 1 battery to chassis ground (you should see the stock battery ground, upgrade the wire) 2 alternator pos to battery pos (run from engine bay to battery in the rear, follow the stock wire) 3 chassis ground to engine block ground (this would be in the engine bay) 2 and 3 make me nervous cause I dont know exactly where and which wire it is. I might wait to see if I get any voltage drop before I do the big 3. I would need more 1/0gauge too. Only have 10 ft of it and a run from the hood to the battery would add another 10. try 1 and see how the bad the voltage drop is. depending on the type of music you listen too and the quality of stock wire, you might be fine. you dont need to replace the oem wire. just do your own run. in fact, i would recommend you leave the stock wire.

The only thing is the battery is in the trunk. The hood is very confusing and I dont know exactly where my routes would go without examples/explanation. the big three in your case would be. 1 battery to chassis ground (you should see the stock battery ground, upgrade the wire) 2 alternator pos to battery pos (run from engine bay to battery in the rear, follow the stock wire) 3 chassis ground to engine block ground (this would be in the engine bay)

are you sure they are both the same coil configuration?