i have to make a box that is 80 litres. Can anyone help me figure out the dimensions. Its doin my head in. Keep gettin size of approx 0.75mx0.75mx0.3m

Think of it this way. 1l = 10cmx10cmx10xm = 1000cm^3
so if you need 80l you will need 80000cm^3.
so a box with the dimensions on 40cm x 40cm x 50cm will achieve that!!

Remember Volume = Area of the base x Hieght
ie V = (LxW) x H

Hope that helps

That size works out to be 170L....you sure you're not calculating ported box?

examples of approximately 80L fully enclosed box...

40 x 40 x 50 = 80L

45 x 45 x 40 = 81L

35 x 45 x 50 = 78L

Hope that helps.

phong =P~

thanks. Im making a box for two type r's. Spec sheet says sealed box size should be 0.7ft cubed - 1.0ft cubed. i boubled this figure and converted it to litres and got 39.6L to 56.6L. So i figured a 40 L box would be ok. I said 80L cos its a triangled box in a corner, but basically half a cube if its cut diagonally. If you get what i maean??

Is 40L too small cos they give a large window of box size. 39- 56??

Type-Rs work best sealed at .7 to 1ft3 - tuned to around 50Hz - due to the effects of cabin gain though Id recommend starting with the largest possible enclosure if its practical - around the 1cu ft mark and if you can get ahold of an SPL meter try placing the box in various locations of the boot and then begin to cut down the internal volume - find the sweet spot then build that size box - you may find the best is facing rearward or aimed at the bootlid - where do you plan on placing the enclosure? - rear corners?

Was this just the one type-R 12" ?

planning on putting the two subs in a corner box in the front left of the boot facing rrh tail light. If that makes sense. Im mainly going for looks but still want a decent bass. Yes .7 to 1 ft is what im going by. So you reccomend lean to the higher end of this???

Yes as its harder to then go larger - start big than you can jig/saw it down and measure...can do it by ear but id if you can get a hold or loan a sound meter would be better....

Is that two subs in their own enclosures or together...or one big enclosure but internally sealed to house a seperate enclosure for each woofer....if its one big enclosure for both you'll need to double the volume and go 2cuft3 - I ran two Type-Rs in this manner before going to 4x 12"S and sealed sounded really good - great output and a nice tight punchy bass notes - was perfect for SQ

really, you reccomend doubling my box size from 40 - 55L to 80-110L? Im making it from fibreglass so cant afford to trial and error?

sorry, yes am running them in same box. was thinking of making two seperate boxes in each corner but want a different look? will two seperate sound better or 2 together. Also, im running 2x 1222d type r 12in subs. Are these the god ones or the bad ones?

Nothing wrong with em at all exactly the same as what I run - and what I meant by doubling the enclosure volume was if you were going sealed (no port) and having both woofers in the one box then yes the recommeded 0.7 to 1cu ft was for one sub therefore 1.4 to 2cuft would be the optimal setup for houseing two - how ever if you will have one box for one woofer each in the corners either side of the car then it will only be 0.7 to 1cu ft required for each...

Soundwise unless you are planning to really get into competition I wouldnt worry what you plan to do will be find and sound awesome.

If 1cuft per sub will be practical for you space wise (if your still planning to keep your boot space) go with the larger otherwise drop down to .8 or so cu ft.

You say you plan to fibreglass - how do plan on ensuring the moulds are identical - as if they are off each enclosure will have a different internal volume and result in the woofers behaving differently which you dont want...where fibreglassing can be an issue...

I plan to sell my side moulds soon too to build a massive enclosure - start building today

nah i think im gonna just make one big box for two. I have more room to make a bigger box. Should i make it bigger than 1.0 ft cubed per sub?

Well i'd start with what do you want out of your system - to compete? daily listening?

What sorta music do you listen too ?

Was there a particular reason you were going sealed - do you care for boot space/spare tyre access etc

am going sealed as it's not as hard to get wrong as ported. Room is not an issue. Have no spare wheel. Would like to compete. Listen to r n b.

Well its only hard until you have a go

When you say compete do you want to compete in SQ (Sound Quality) or SPL (Sound Pressure Level) competition.

If its SPL ported is by far the better option - ported is the more efficient option when going SQ also however as we've discussed slightly harder to achieve the optimum outcome and will sacrifice more space - again all dependant on which outcome you hope too achieve

What amplifier did you have again to feed these two twelves?

Note: Also a 2cuft ideal for SQ wedge enclosure will just fit neat behind the seats for two 12"s..

i have an mrd1001 alpine v12 mono. Im not worried about space so if you think a 2cu/ft box will be ok then thats what ill build. I want to invert the subs too.
As for compete, i mainly am concerned about looks but want a decent bass outcome.
Thanks for help.