cobra93

The inside of the enclosure is 11 3/4" wide. The outside dimensions of the enclosure are 48" x 17" x 14".

First off, to those who have helped me with my mid bass thread. I'm still planning/ listening as time allows. Thank you, to those that have offered help , you know who you are, it's greatly appreciated and I should have some updates soon. O.K., I figured I'd better get off my ass now that i have some time and get the subwoofer box on its way. This is an enclosure for 4 sa-8's, 3.6 c.f. (net) tuned to 33 hertz with 52.875" of port. It will be driven by a sundown saz-2000d @ 1 ohm. This is going in my 2000 ranger extended cab pickup. Everybody has seen enclosures with kerfed ports, but not like this one I'd bet. I was originally going to do a double kerfed port, but in the end it wasn't worth it from a stability standpoint. I found a good price on some 11 ply Baltic Birch so I picked up 2 sheets. After working with this I'll never go back to MDF again. It's not void free, but it should be fine. This was my helper, until the saw fired up. (neighborhood buddy, My brother has 5) I tried to kerf some mdf, but didn't have much luck with a 2" inside radius., so I went with what I know. Steel, (11ga.) which I "nipped" into these radii ( 2" i.d., 2 3/4" o.d. and 7 1/4" i.d.) I don't have a router, only a circular saw, jigsaw and a drill. I need to route out some material so the steel kerfs would be flush with the surface of the wood. I then got out my "circu-router" and proceeded to do just that. I cut the first hole and thought,"I'd better check the fit (woofer porn to follow). I forgot how big the motor on the sa-8 was until these pics. it fit quite well. It looks like it's time to mow the driveway again. Let's start getting this together. I don't have the patients to wait for glue to dry, so we glue and screw. I figured I'd paint the port while I had a good angle at it. I may go with a charcoal instead. It depends on the fabric i choose to cover it in, black or gray, like trunk carpeting. I haven't decided yet. A few more panels glued and screwed. It was getting late, so I stopped taking pics til I was almost finished. I will paint the area around the woofers to match the port, gray or black. I can't wait to hear this. I've got the last of the electrical coming on tues.. I still need to do that, 4 runs off 1/0 kolossus flex and some 4 awg. runs as well as a new alternator, big 3 and weld up an amprack/enclosure frame. I hope you enjoyed the pics.

im using WinISD but i was wanting a slot port not a tube one. and it has the gas tank behind the seat so when i get my box build im getting some kind of auxiliary tank for the bed. when its out i got about 70"x25"x10" to use. I haven't used winisd much. I bought bbp6 a long time ago, so I use that a pencil and paper or both. Good luck, post pics when you get started.

Do you have the mid's? If you do give it a try and see what it sounds like to you, after all it's your money and your opinion that matters.

I don't know what amp you were going to use? What about two mono amps , one for each side. You might be able to get away with a class D.

I assume you are asking if driving the left and right mid bass speakers off the same mono amp would sound o.k. in the 250-90 hertz region. If you are, are you looking for sound quality or just some punch to help blend the wall in with the front stage?

No, that's not correct. What program are you using? A 2" dia. port in that box (10" x 15" x 9"outside dim, @ .428 C.F.) would be almost 16" long. I've got an extended cab ranger (2000) and I've got 4 sa-8's for it. How are you going to fit them in a standard cab? Blow through ?

I may have the T/S parameters, I'll look and post back tomorrow.

How did the grills Jroadtatts recommend work out clearance wise? Vids? The build looks great.

hahah that what i was wondering JLs just pop to me on high notes.... all my friends with jl say its there car rattleing. im like your a dumb ass its comin from the cone... The reason I asked if it was a JL amp (slash series) is because mine had an issue playing a eclipse 88120 dvc in a sealed enclosure @2 ohms. The low ohm light would flicker on for a split second and there was a popping noise coming from the sub when this occurred. I noticed it one day with the car in the garage (dark) while I was doing some tuning.

That's awesome, what a way to start my day.

O.K. , thanks to both of you. Isn't the internet a wonderful thing.

Not half of the voltage. That is incorrect. You would multiple your "passband" voltage by .707, and that would give you the target voltage for the crossover, or the -3db point of the signal. We can verify this with Ohms Law, which I'll show down below. You could just start with an 80hz tone and leave the crossover off (assuming it has an "off" switch or the range is adjustable enough to leave the initial signal unaffected). But you wouldn't have a target voltage of 10V for the -3db point. The target voltage for the -3db point, based on a 20V starting voltage, would be 14.14V. We can verify this back with Ohms Law. For example purposes, we'll pretend load (speaker) is 4ohm. 20V^2/4ohm = 100w 14.14V^2/4ohm = 49.9w (we'll just round this up to an even 50) 10*log(100/50) = 3db So, we just verified the difference in voltage is 3db The reason the target voltage for the -3db point of the signal is .707 and not half is because the decibel difference for voltage is a 20*log function and not a 10*log function like power output differences are. 20*log(1/.707) = 3db Half voltage would instead be -6db. I believe your math to be correct, but I haven't done anything relating to logarithms since high school (I'm 38 now). I'll have to do some brushing up. Since I can't reproduce the math (10/20 log) I'm lost, but I'll figure it out. Thank you for a definitive answer to my question, and by the way, that was fast.

I'm looking at your sig., You're running 2 18"'s in a ported enclosure. How did you set your infrasonic/subsonic crossover? Did you just play test tone while watching the subs excursion? Thanks for your reply. Does any of what I said make sense to you?

I've searched for answers, but I've not been able to find anything definitive. Sorry, this will not be a short question. On most crossovers that we find on car amplifiers, there is a range silk screened on the crossover, let's say 50 hz. -500 hz. I don't know if the slope actually matters if you can get far enough away from the crossover point or disable the crossover. I believe that the setting on the crossover is the -3bd down point, but there isn't a way to know what your setting it to by looking at the potentiometer and the numbers on the amp. Allot of things I've read on this topic are extremely vague. Maybe I'm not asking the question correctly in my search. Such as > "start with the crossover at **hertz and adjust from there until it sounds good." I understand that I shouldn't be caught up with the exact frequency, but rather what sounds correct. However, in the case of an infrasonic/subsonic crossover or a narrow band pass (mid bass) or playing a tweeter too low, I'd like to get the frequency as close as possible to start. I've possibly been spoiled by JL slash amplifier's crossovers, they give you a chart that tells you the crossover frequency at every click in the crossovers range. Is the information accurate, I don't know. That's the point of my question. I've read reviews in different magazines before that stated the range the crossover covers is not accurate to what the numbers are telling you (overall span). As I understand it, at a crossovers -3db down point the amplifier should produce 1/2 the target voltage with a test tone. I don't believe the crossovers slope is relevant if I'm high passing a component set for instance and can get far enough away from the target frequency. Correct me if I'm wrong. Let's say I'm looking for an 80 hertz high pass on a set of component/coax speakers and the target voltage is 20 volts. If I measure a test tone at 1000 hertz (well out of the crossovers range) and have 20 volts output at the speaker outputs of the amp. Does that mean I should play an 80 hertz tone and adjust the crossover frequency until the measured output form the amplifier is 10 volts at 80 hertz? If this is true, then I'd assume setting a band pass crossover for a mid bass speaker( 80hz.-250hz.) would be to find the target voltage with the high and low pass crossovers disabled and proceed to find the 1/2 voltage output for the high/low pass points. Is this correct? Please no short answers. If you can provide a link to answer my question I'm happy to read it. Thank you for your time.

What amp are you sing to power this sub? How do you have it wired, series or parallel? It's not a JL is it?

Since nobody else has chimed in, I'll give you my experience with kerfing. I originally tried a 2" id, 2 3/4" od, it didn't work out so well. I couldn't get all of the cuts to bend the same before one of them split (no matter how thin/thick the material I left was). I believe the radius was too small and this was my first attempt at kerfing. I'm a steel fabricator by trade, so I went with what I know and nipped some 11 gauge steel to the radius needed so I didn't have to redesign the enclosure. I've found a very limited amount of information on this subject. My advice to you is to start with a 4" or 5" radius (practicing) and try to go smaller form there. You'll find your limits and can redesign your enclosure with the smallest kerf you can achieve, if necessary. Your only kerfing the end of your port so a larger radius shouldn't change your tuning much. Any radius you can achieve will be better than the port just stopping as you're only creating a smoother transition to the environment outside of the enclosure. I remember seeing Jacob post a thread, on sundown audio's forum, where he used bending plywood and spacer blocks to achieve his kerf (like a sandwich). Good luck and post back with pics when you get something working.

He needs to support the amplifier, not the subwoofer (unless he changes the load/demand placed on the amplifier). He never said he's changing the amplifier, at least not that I read.

You've stated that the BL 15" isn't loud enough and what you've done to the car ('08 tc), but you didn't state (and no one has asked) what was/is the specs. of the enclosure the BL is in. How is it installed in your car and so on. This may help some of the people that are trying to help you. Better buckle the chin strap to.

Unless your door skins are made from aluminum, you are not going to weld any aluminum bars to it. Soldiering or brazing on the other hand could be feasible, but presents the same problem, repainting the door, as well as distorting the sheet metal. You may be able to glue or epoxy the bars to the door skin, I don't know what may or may not work, but a quick search will answer your questions. AS Impious stated (and as I'm doing in my own doors) looking into a sealed enclosure in the door does wonders for rattles created by the back wave of the speakers mounted "in" the door. I placed 1 8w3 in a sealed enclosure in each door powered by a 500/1 and the mirrors barely move, it's a wonderful thing. Good luck.

As I understand it, in a sealed enclosure your impedance will never go below your static ohm load (2ohm's). Only in a vented enclosure can it go below your static ohm load (according to a kicker rep I spoke to a long time ago). Since you seem to understand the difference between D.C. resistance (1.4 ohm's) and the load the amp will see (A.C., 2 ohm's static and higher) I'd assume you realize you'll probably not see the rated power at your sub ever (listening to music). There are allot of people on this forum that understand this better than I do and I'm sure they'll give you the answers you're looking for. I'd go bigger than the 2500d if I were you, I'd rather have more then I need than wish I had more than I'd bought. Sorry I can't help with the alpine issue, but that's my 2 cents.

So this is a bait-n-switch?

something like this splice connector You could look for some copper tubing the same size as the wire, probably cheaper, and soldier them in.

Damn it J, I'm seriously jealous over here!! :drink40: Looks like your doing a hell of a job on that door so far. BTW, It hates you right about now, ya know. :morepower1:

you could buy some wire couplers and soldier extensions onto the existing (if your sure they won't reach) or just replace the wires when you change the battery out. If you use 4ga. wire it won't be that expensive.