RL-P18 End Table Help

[jimndess]

Hey whats up guys,,,somewhat of a noob here,,,was looking to see if I could ask you guys a question or two about a project im wanting to start using 1- RL-P18.

Im wanting to build something along the lines of a coffee table, id say about 30" square by about 18" high internal dims, with an RL-P18, do you guys think thats big enough for a sealed enclosure for this sub if id like it tuned in the teens.

Or second option is if i keep those same internal dims,,,but somehow port the box? Id like to do a nice furniture type piece with a granite slab on top of it,,,so id rather not port throught the top of it,,,maybe slotted ports somehow??

Not sure,,hope I can get some insight from you soundsplinter pros,,,or maybe a diff idea than what im thinking.

Thanks...let me know if you need more info from me.

Jimmy

[robertcharles123]

Rpl 18 needs lots of space. look at scottsimoneans 25 cf boxes as example. Dan knows his stuff. Just model the drivers in winisd and you will see. Do you knowhow to use winisd?

good luck,

robert

[robertcharles123]

Do you have the drivers already, or just an idea brewing?

[robertcharles123]

just going by website the sealed need 7cf, ported net 12.8 tuned to 18 hz. Can you get these volumes?

[jimndess]

Thanks Robert,,,,as for the driver No I dont have it yet, but ive been looking around for a bit and it was down to either the RL or a Maelstrom,,,the looks of the RL kind of swayed me over to it.

2...Ive seen scotts 25cf boxes, but I definately cant go that big.

As for the design on the box,,,I think ive found something I like and can tweak a bit,,,roughtly 24" wide x 24" deep x 30" high internal,,,,that should be ok for a sealed RL right?

[robertcharles123]

are those internal or external measurements? including all bracing and driver? i think above 7 feet will get you there sealed. lots of power needed to really get that woofer moving in that setup.

[robertcharles123]

i modeled it in a 9.56cf sealed and 1000 watts seems to be max power for that setup to get xmax. i will try to ost results, but am having trouble.

[jimndess]

Thanks Robert for your patience and help by the way,,,well downloaded winisd and have been playing with it but not quite sure yet how to read everything...but ive been playing as if my box was going to be 14.5 cu ft,,,which I think I can pull off a with a 28" x 28" x 32" internal,,,if i do keep those dims given the size of the box would i be better off keeping it sealed?

I am curious about 1 thing on ported enclosures,,,im still somewhat new to HT subs, but in car subs ive had ported boxes with port tubes inside having elbows in them to make them seem longer,,,,is that something thats not done in HT subs,,,again still a noob so im not sure

[Mike P.]

Here's a database of all subs that have been posted here. This should give you an idea of the volumes that work well with the RL-p18.

http://www.hometheatershack.com/foru...-database.html

Port tubes can be used with elbows in HT subs.

http://www.hometheatershack.com/foru...8-4-build.html

There is a pair of RL-p18's that were just posted in the classifieds, might be worth checking it out.

http://www.hometheatershack.com/foru...rs-subwoofers/

[jimndess]

ok im back with my redrawn plan,,,16.6 cu ft using a 30" x 30" x 32"high internal dims, with a end table/furniture look to it, plan on having 6" legs on it, with the sub downfiring onto the hardwood floors,,,been playing with winisd but need a little help,,i used the normal port dims on there and for a 15hz tune with a 6" port the length is managable.

My question is do you guys think itll be fine to have the port downfiring as well or should i try to port it through one of the sides or even the top.

Second question; im able to get 8" diam pvc fairly easy, would it be better to use an 8" port over a 6" diam port on this build? and if so how do i find out how long of a 8" port to use if winisd only goes to 6".

thanks guys,,,,patiently waiting, hoping for an answer

[thxgoon]

Porting on top or bottom shouldn't matter, I would go for the bottom myself. You can type in 8" in the box where the pull down menu is in WinISD, it will then give you the correct length.

[jimndess]

Just a little more picking of your brains....So ive pretty much narrowed it down to what i would like to build, but ive narrowed it down to 2 diff options---now im stuck and not really sure which way I should go.

Going to use 1-18"RLp-18, powered with a ep2500.

If you guys had the option would you:

A. Take a 16.6 cu ft vented box with a 14hz tune
or
B. A 13 cu ft sealed box

Ive been playing with the two options on win isd, but not a pro on it so im not real sure what i should be looking out for, or if theres things i should not do with this woofer..

Anyone got any opinions on these 2 boxes.

Thanks.
Jimmy

[thxgoon]

Well from the looks of things both designs are pretty well maxed out with the power from an EP2500, which is a good thing. The sealed design will exceed xmax at around 30hz with 1500 watts of power as will the ported design, but the ported design then needs less excursion down deeper as compared to the sealed design. As a result you can achieve significantly more output from the ported design. The only reason I would consider going sealed is if enclosure size were in issue (which it doesn't sound like it is).

Ported will give you more efficiency, higher output, lower distortion, deeper extension, less eq. If designed properly there is no downside to this design.

[Mike P.]

16.6 cu ft tuned to 14 hz would give you the most output down low. The ported would have 10 db more output at 15 hz compared to the sealed. Both models are with 1000 watts input, Xmax is not exceeded with the use of subsonic filters.

[Ricci]

A sealed box for this driver only needs to be around 7cu ft.