Ok I have 3 Alpine Type R 12's, 2 are dual 2 ohm 1 is dual 4 ohm, a MRD M1000 for the 2 dual 2 ohm subs, and the MRD M500 for the one singe dual 4 ohm... so basically both amps get 2 ohm load and each sub gets 500 watts RMS. If you saw the update thread I posted in photos and media I just did the rear seat delete today. The subs are gonna be all 3 in a row acrost the rear seat area. I wnt to port them, I was thinking 3 seperat eboxes slot ports acrost the bottom.... guestion is what am I looking at in terms of design, I don't know anythign about figure out port size ect.. The subs are the rounded suround style subs, not the folded suround. I'm not just looking to get loud I want it to sound good doing it. Oh and for the fronts I have another V12 amp for 2 sets of 6.5" type R components for the front doors.
About 6 cubes 2 33-34 hz would be nice with about 90-100sq.in. of port.
Just put them in 1 common chamber...it'll be fine. Building 3 boxes would be a waste.
If you do a 7.5 cube box (total...without sub and port displacement) with 100 sq.in. of port (20" x5" for example....20x5=100) the port will need to be 26" long to tune it at 33hz. If you take off the port displacement (100 x26=2600 cubic inches/1728 = 1.5 cubic feet) you have 6 cubes net.
RE Audio
all im gonna say is damn tahts gonna sound nice and hit hard! my bros got 2 alpine typ r 12s custom fiberglassd into his trunk wit a west coast custom amp... i think 1000 watts :? neways i would do one box and mayb angle it. i would have a setup like this....... the ^s incidate direction of sub. this would b the upper view of it. (and a little off scale but to give u idea) have the ass of one of the sub stickn out at u and the other to firing in.... all of this would b pointd at the driver and amps on back of box. well thats my idea. ne questions let me know i can draw in more detail and let ya know
sub
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sub / ^ \ sub
/ > < \
/ \
Isn't it not good to have mutiple subs in the same box when they aren't all powered by the same amp? I've always heard its a beoth to tune it that way, I was just gonna make 3 individual smaller boxes... not actually 3 boxes, more or less a 3 chamber single box, each chamber with a port and a sub
oh and isn't 2 cubes per sub alittle big for the type R's? I knwo they like small boxes
it'll be easier tuning the one chamber compared to the three. the amp is not going to be exactly half of the mrd-m1000. in fact i think the mrd-m500 is 550watts rms. if all of the airspace is split, the xmax will be higher with the single dual4.
darkstars: thats about 2 cubes a sub, which isnt too big when its ported. if it was sealed then it'd prob wouldnt work. one chamber is much easier than 3 individual's. the hard part with having multi amps powering diff subs is getting the gain right so one sub doesnt overpower the others. but that can be done by ear or if you have an oscilloscope that'd work too, although i wouldnt buy one for just one install. the wiring is gonna be a pain, why did you go with 2 diff voicecoil setups?
I went with 2 differnet voicecoil setups so each amp coudl see 2 ohm load.... I had the MRD-M1000 and the 2 dual 2 hom in my last setup, I deiceded to go with 3 subs instead of 4. I could have goteen another dual 2 ohm sub but that would mean getting another MRD-M1000 which is very hrd to come buy and still $500+ only to run it at 4 ohms and only get 1/2 the output and have a physically huge amp to mount, so I went with the dual 4 ohm and the smaller amp, basically boils down to it being the same thing over but for about 1/3 the cost.
And I do have acess to a VAS 5051B (VW's top of the line scan tool, its a scan tool plus has all the built in @!#$ of a multimeter, lab scope, and o-scope)
And eaither the subs would see different outputs, the birthsheet form the big amp I already have was 1112 RMS
so if I build a 7.5 cubic foot box how should I go about making the ports? premade port tubes or slot port it or what? Should I have just 1 port? I was picturing ports along the bottom the subs on top but I can I evern run 3 slot ports? like one under each sub?
Sure...just make sure you have around 30-35 sq.in. of port for each sub. For example...you could have 3 ports... each port being 12.5" wide x 2.5" high (length would depend on tuning). It would just be alot of extra work.
RE Audio
how do I determine port lenth for the proper tuneing?
by the way I'm fine with just doing one port but I'm hoping for more exact dimensions on what I should be running, also where should I port it? out the front under the subs, out the fornt on top of the subs, out the top at the rear windsheild?
Not sure where you should put the port, it depends on where you're positioning the box.
But for 1 port, in 7.5cubes at 33hz
Diameter: 7.5"
Length: 9.1"
Should work for you.
looks like you have the hardest part down then. the box will be easy if you're good with your hands and take EXACT measurements. remember measure 3x cut once....and do the cuts yourself, homedepot/lowes blows for wood cuts.
BradSk88 wrote:Not sure where you should put the port, it depends on where you're positioning the box.
But for 1 port, in 7.5cubes at 33hz
Diameter: 7.5"
Length: 9.1"
Should work for you.
a 7.5" round is only 44 sq. in.
RE Audio
For the port...it dosent matter all that much as long as it out the front. You can put it where ever..but forward facing will be best. Along the top or bottom would look nice.
For the box dimensions....you'll have to figure that out yourself. You have to play around with different dimensions to make it fit. I can help you with port length though.
If you have 98 sq.in. of port....say a 28" wide x 3.5" tall port (a 1:8 W/H ratio is a good idea to syick with to help eliminate port noise)...the lengths will be as follows...
30hz:29.2"
31: 26.7"
32: 24.5"
33: 22.4"
34: 20.54"
35: 18.8"
RE Audio
Whoops, yeah. Messed up my formula >
