15 rl-p and nex box

[$$mok3d 0]

Im not very impressed by my first box build go figure. Its more of a cube shape than a rectangle and it doesnt fit in my trunk flush like i wanted it to. So i need to build a new box now. Im running the rl-p off an ED 9.1 at 2ohms and i want a box that will hit the lows very well. i was thinking 16x12x25 made out of 3/4 mdf. would this enclosure be ideal for good low end extension?

[haydenlake 0]

Im not very impressed by my first box build go figure.  Its more of a cube shape than a rectangle and it doesnt fit in my trunk flush like i wanted it to. So i need to build a new box now. Im running the rl-p off an ED 9.1 at 2ohms and i want a box that will hit the lows very well.  i was thinking 16x12x25 made out of 3/4 mdf. would this enclosure be ideal for good low end extension?

<{POST_SNAPBACK}>

Okay, I'm assuming you built a sealed box. So if the specs above are the internal dimensions that would yeild a box around 2.78 cuft which should provide good deep extension with a 15.

If you want help from the forum considering telling us why you are disapointed with your first box (ascetics, sound, ect) and it makes it easier to trouble shoot.

I don't know what kind of tools and materials you have access to but that could help if I knew. If you are going for a nice blend in type install I would go with fiberglass (its not a hard as it might sound and there are a million online tutuorials to help you).

If you don't like your current box (in terms of sound) go ahead and make sure it is the box, sometimes things are just rattling in the trunk or your amp isn't set up right.

To test subs I usually just play them off of my car amp with a long wire in my yard or somewhere that there are no cabin gains or other vibrating things. its really easier to diagnose things this way.

-make sure you build it strong and it doens't leak, you could add a few pounds of polyfill to make the box seem bigger to the speaker yet retain some of your trunk space.

If you really want lows build a large ported box and tune it way low (example 5 cu. ft tuned to 20hz) but keep in mind this would easily be a 140lbs box!

later,

b

[SoundSplinter 1]

Right on Haydenlake, though for the low-end monster box on the 15, I would suggest a slightly more practical 3.5 cu ft net internal volume @ 24-25 Hz (the 5 cu ft would be too peaky in my opinion)... and of course I will reiterate that for in-car use I think this size and tuning is unecssary and would aim for around 2.85 - 3.0 cu ft net @ 28-32 Hz tuning, but for home theater the larger lower box would be bangin' (3.5 @ 25 on a RL-p15 is what I'm currently using in my own home theater )!

Definitely fill us in a bit more as to what your main concerns are at the moment aside from the aesthetic flush mounting for your trunk. Also would like to know more details on your current enclosure.

[$$mok3d 0]

Well my box now is 17h19.5w18l 3/4mdf sealed. It doesnt seem to hit the low frequencies well and i dont know if it matters that its facing the drivers side trunk area in my millenia. I had a 4 cu.ft box in there before with 2 jl 12's so a ported enclsoure might be nice. I have a maximum space of 32long 16high 19deep . would that be large enough to make a low end monster box?

[60ndown 0]

Well my box now is 17h19.5w18l 3/4mdf sealed. It doesnt seem to hit the low frequencies well and i dont know if it matters that its facing the drivers side trunk area in my millenia. I had a 4 cu.ft box in there before with 2 jl 12's so a ported enclsoure might be nice. I have a maximum space of 32long 16high 19deep . would that be large enough to make a low end monster box?

<{POST_SNAPBACK}>

x over the amp @ 60hz and turn the gain up=low end monster

[SoundSplinter 1]

Hrmm.. your box seems to be around 2.8 cu ft net volume. I like to keep my RL-p15's in sealed enclosures between 1.75 - 2.25 cu ft net volume. If you're really craving more output over the low-frequencies, perhaps you indeed should go with a ported box. With about 5 cubic feet to work with, you should be able to squeeze a 2.5 cu ft net internal volume tuned to 28 Hz in there.. and I say go for it!

[Aaron Clinton 2,372]

Hrmm.. your box seems to be around 2.8 cu ft net volume.  I like to keep my RL-p15's in sealed enclosures between 1.75 - 2.25 cu ft net volume.  If you're really craving more output over the low-frequencies, perhaps you indeed should go with a ported box.  With about 5 cubic feet to work with, you should be able to squeeze a 2.5 cu ft net internal volume tuned to 28 Hz in there.. and I say go for it!

[$$mok3d 0]

Im not so good at designing boxes but here is what i came up with.

32wx16hx13l gets me 2.95 cu.ft minus the .21 driver displacement i get 2.74 cu.ft internal volume. then for a tuning of 28hz i get a port length of 12.8 inches for a 4 in round port. can someone please tell me if these calculations are correct?

[SoundSplinter 1]

Looks pretty good to me. I'm getting 2.733 cu ft after displacements, making for a 4" round port that would be 12.88 inches long to achieve the tuning frequency of 28 Hz.

[$$mok3d 0]

if i used 2 4" ports would they be 6.4" long each?

[ANeonRider 3]

Nope.

[$$mok3d 0]

How would i figure out the length of 2 4" ports?

[///M5 2,833]

assuming the box is 2.733 cuft and the port being 4" round an internal I get:

1 of 4" port -->13.39" (port volume 0.097, box 2.636)

2 of 4" port-->36.13" (port volume 0.525, box 2.208)

DISCLAIMER: Please do not use these without checking with someone, I just used the BCAE calculator and did not verify that they are right.

On a positive note--and the reason for my response--the order of magnitude between the two is surely about right so if we were asking to try and get your box closer to the recommended 2.25ft using dual ports will get you closer!

[mrray13 30]

the bcae calculator is asking for NET volume of enclosure...so u'd have to figure port displacment AFTER u get the length...

so, if ur after the recommened 2.25ft^3 with two 4" ports, tuned to 28hz...

the ports will be 35.5" long (showed 35.47, but i rounded up..isn't going to change anything.)

so u will have to build a box with a gross internal volume of 3.12ft^3 to get the above mentioned numbers...

edited..i forgot to figure in two ports...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[$$mok3d 0]

Ok i understand now back to the drawing board. ill come up with a new plan with the port displacement calculated in.