Home Theater Forum and Systems banner

SS Rl-p15" - my first DIY Box Sub

17K views 59 replies 11 participants last post by  Egil 
#1 ·
Hello all!


I recently sold my PB12Ultra, - because I started getting the upgraditus itch, after reading more and more about the new PB13U that'll come. But at the same time, I was lurking around some DIY forums, - and got this "urge" to make one myself instead.

The choice was between a TCsounds 2000 15" and the SS Rlp-15". I wen't with the SS - and I should receive it in a couple of weeks, I hope.

Mike from SS recommended that I built a 200 litres enclosure, tuned to 17hz. Powered by 800-1000watt. If im going to tune the sub to 17hz, the pipe has to be 1meter, and have a diameter of 17cm, which is roughly 35 square inches of port area.

The thing is, I jus't can't find a pipe that has a diameter of 17cm. I can get a 6" PVC pipe (which is rougly 16cm in diameter, - but the INNER diameter will be 15.2cm with that pipe). The next closest thing I can get, is a cardboard pipe, that has an inner diameter of 19cm (im not 100% sure if it's 19cm INNER diameter, it may be 18.2cm inner diameter).

Also! I would prefer having a bit shorter pipe, so the box itself isn't that HUGE. Mike said that if I tuned the subwoofer to 19hz (with that 17cm in diameter pipe), I could shorten the length with 25.5cm.. So I think I will go for a bit higher tuning (19hz), so the pipe doesn't have to be that long.

So my main concern right now, is, should I go with 6" pipe (that has rougly 15.2cm inner diameter), or the cardboard pipe that has 19 (or 18.2cm) inner diameter ? (Mike said that a smaller port area than 35square inches might cause port noise - but he also said that It would most likely not be an issue unless I sit right next to the subwoofer). And - how can I calculate how long the pipe will be (in order to get the right tuning on the sub) ?

I guess I can mention that I plan on using a Behringer EP2500 to drive the subwoofer. .. And that this is my first DIY project, so im a bit green when it comes to TS parameters (and how to calculate length on the pipe etc). But I do have the skill to make the box at least.. I hope :)
 
See less See more
#4 · (Edited)
Hey, - it is the dual 2 ohm I've bought.

Thank you for your calculations - I will go for the 6" flared port, - and tune my sub to 19hz.


If you look at this picture:


Adding a 'flare' on both ends - is the actual size on the pipe stil 62.6cm then- or is it ~65cm as shown on the picture?

And when it comes to the flare itself.. I hope it's not to hard to make one myself, and glue it on the pipe.. I guess it has to be really smooth.. I'll do some research on that :)

Edit: From what I've read, even when adding a flare, - the actual length is still 62.6cm. I also hope I can buy a 6" flare somewhere in Norway.. so I don't have to make one myself - or order one from the US (not that it's a problem, it's just the waiting that would kill me :D )
 
#6 ·
If you're making your own flares, follow this principle:

The generally accepted adjustment is to subtract half the flare radius from the physical length to obtain the effective length. If both ends of the port are flared, the adjustment is done for each flare

 
#10 ·
If you're making your own flares, follow this principle:

The generally accepted adjustment is to subtract half the flare radius from the physical length to obtain the effective length. If both ends of the port are flared, the adjustment is done for each flare
If I understand your picture correctly, the "cutoff" point is at half the flare depth, not half the flare radius, right? I'm not trying to be ****, I just want to make sure I'm understanding correctly.
 
#8 ·
I was actually going to ask about that.. :)

I plan on crossing my fronts to either 100 or 80hz, let the MBM-12 take of the frequencies from 100 (or 80hz) down to 50hz. The subwoofer im making, will take care of bass from 50hz and down.

In order to cut the subwoofer at the right frequencies, - and to prevent it from bottoming, will this: http://www.behringer.com/CX3400/index.cfm?lang=ENG do the trick ? Or do you have something else/better to recommend? :)

Btw: Thanks for that picture - it's quite helpful if im going to make one myself:)
 
#15 ·
Assuming I build a cube that is 71x71x71cm, and use 1" MDF, - I will get around ~287 net litres. Then I have to subtract some volume for bracing (X litres), and the tuning pipe (around 11-12 litres)..Which should do it, I hope :)

I will probably make some 'donuts' for both ends, using 1 or 2x 1" mdf. It's probably not optimal making this myself, but better than using no flare, I hope :)

Also: Is there any pro/cons building a cube ?
 
#16 ·
You don't have to build a cube. You can build it tall with the same volume. With a taller box, you can tune it lower if you want to 14hz. 6"X28" port.

I modeled for a flared port and not. No difference. So I didn't bother the extra work. It'll sound great regardless.

 
#17 · (Edited)
Aha.. :) so as long as the net volume is right, it doesn't matter which shape it has.

For my use, I don't think it is necessary to tune it any lower than 17hz, so I'll probably just go with a cube design, similar to yours :)

WOAH, things are finally starting to look good :) Now I just need to get a hold on some 1" mdf to begin the project !



Should give me the net volume of ~287litres... -bracing and tuning pipe, this should be around 260litres. Can't build a cube 71x71x71 because it wouldn't fit through the door to my living room :D
 
#18 ·
#21 · (Edited)
Ty, Jerm.


Im having problems getting some 25mm MDF (1").. I currently have 3 choices:

1) 19mm MDF (~3/4" - cheapest).. The minimal size recommended.. but will this be rigid enough for my 260l box?
2) 30mm MDF (about double the price as the 19mm) - box will be a bit bigger with this, but that is not a problem.
3) 22mm MDF - but then I have to wait 2-6 weeks.. and I don't think I have the patience to wait that long :D

Any suggestions ?


Also: It doesn't matter if the port/pipe is horizontal or vertical, right ? (Im considering building the box a bit taller so I can tune it lower).
 
#22 ·
The SMS has a pretty steep low end rolloff, so that can act as your highpass. You'll want some flaring for the port opening - what most of us do is use a 3/4" roundover bit where the port meets the MDF to create a DIY flare. Collo's "Flare-It" program will show what effect even minimal flaring has.

The orientation of the port doesn't matter, just avoid any bends and make sure the internal port opening has plenty of clearance, at least 6" in all directions.
 
#23 · (Edited)
All I can tell you is that I just used 3/4" MDF for my 8.5cf and have had no problems. If you look in my build thread I just used 2 pieces of 3/4" for the top and three for the bottom with three horizontal braces and vertical braces an all four walls. Heres a picture, the last picture is the piece I used to get three pieces on the bottom of the sub. I just glued the two pieces together. It allowes the driver to be flush and still have 1.5" for the driver to screw into.
 

Attachments

#24 ·
Looking good, Jerm :)

I just picked up all the parts (precut) for my box.. 3/4" MDF.
Im not that happy with the cutting..(have to cut 2-3mm from some of the pieces myself, - because I want it to be perfect :p ).

Anyways..

At least I can start building this behemoth now :) Will still be a couple of weeks before I receive the woofer, so I got plenty of time , still
 
#26 ·
I was originally going to build a box similar to yours. But instead, I ended up with a box with these dimensions: 64(W)x 63(L)x 89(H)cm. Since my box will be that high, I'll just use a port ~30" Long, so it will be tuned to around 15hz. Internal volume will be around 293litres... and 260litres net volume (when subtracting the tuning pipe+bracing).

Oh and btw - I can't wait for the results either. Hehe.. Hopefully it'll go smooth :)
 
#28 · (Edited)
I've been quite busy lately (*cough*), - but I will start putting the box together today. And pictures will come, of course :) I put the box 'together' yesterday (as in, no glue no anything, I just wanted to see how the parts fit).. and well, it's like this classic; "You know it will be big,- but you don't really realize HOW BIG, before you see it first hand! (Or something like that, hehe).

Btw. Im thinking about just ordering a pro-amp for the woofer. But there is a couple of things im wondering about (That I haven't researched yet):

1) Will I get better 'sound quality' if I buy a better pro-amp than the EP2500? (for example, a similar powered QSC amp?)
2) How exactly do I power the RLP15" ? There are 2 +/- connectors on the woofer itself, should I wire them so the EP2500 gives each connector 1200watt? Edit: 2400watt on ONE woofer = LOW gain.. and = NO, this is not how to wire it, I guess :p
 
#30 · (Edited)
Thanks. Great illustration !

Little update on my project:

After removing some mm from 2 of the plates (By using a router), - we (as in, me and my father) started putting the box together. We started by gluing/screwing 2 of the side plates:


We glued/screwed 3 of the plates together, then we turned the whole shabang 180 degrees and screwed/glued the bottom plate to it..:


A closer look:


And the whole thing:


Not the best picture quality.. because they are taken with my cellphone.

I will 'stiffen' the entire cabinet next. By adding bracing etc.. and adding the tuning pipe (I will flare both ends, using this technique, http://www.subwoofer-builder.com/flares-10mm.htm - I think).
 
#31 ·
One of the inner bracings:


This 'bracing' will be at the bottom of my box (I will use lots of sicaflex to tighten it)


Now, this is how I will make the flare at the end of the pipe:


I have a couple of questions I hope someone can answer:

At 1. I will use this technique:
(From http://www.subwoofer-builder.com/flares-10mm.htm ). Do I have to use that same technique on 2. ? Or can I just leave that sharp edge alone?

If you look at my bracing masterpiece - do I need to render the edges, to make it as smooth as possible ?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top