RL-P18 Ported Subwoofer Build - Jan 2009

**Ukwarrior** · **01-03-09, 12:46 PM**

Hi,
As some of you know I've been planning to build a subwoofer : (Link to design thread)

http://www.hometheatershack.com/foru...8-drivers.html

I chose the Soundsplinter RL-P18 and Mike has been very helpful in processing and shipping the unit. However, at present there are no 18" gaskets in stock so I won't have a nice surround for the driver until May! However, I have some PE Gasket tape and it should do a fine job.

A parts express order recently arrived with some of the accessories necessary for construction.

I also placed an order with a German company called Viablue who supply excellent audio parts. I intend to build my own speaker cables and finish the enclosure to the highest quality.

Viablue Audio parts :
4 x Spade Connectors
2 x Sc-2 Splitters
5m Redline Cable sleeve

Parts Express Hurricane Nuts & Speaker Mounting Bolts

Dayton Audio Spikes

The binding post plate consists of a Dayton Audio mounting plate, Dayton Audio Insulated Gold Binding Posts & Viablue TS-1 Gold 8mm spade connectors

Speaker Grill cloth & 1/2 inch by 1/8 inch PE gasket tape

Current Audio Setup -
Cambridge Audio 540a integrated amplifier
Audiolab 8000P Power amplifier
Edirol FA-101
1 x Pair floor standing speakers - Aegis Evo Ones
2 x Pairs Aegis Evo Threes (Bookshelves - one pair will eventually be mounted on wall mounts and one pair on speaker stands)

That's it for now, I'll continue when the Driver arrives.

Ed.

**Jerm357** · **01-04-09, 07:15 PM**

Looks like someone going to have some fun.

So whats your final design plan going to be?

**Ukwarrior** · **01-06-09, 03:53 PM**

I'm thinking of going for a 520L enclosure with a single 8 inch port somewhere in the region of 27 inches. I don't have my exact measurements yet because my PC is down and my mac doesn't run WinISD! So, I'll have to wait a few days until I can finalize designs - Cad renderings to follow!

Good News - The SS driver has cleared customs today (despite hefty import duties) so I may be able to collect it tomorrow!

Ed.

**Mike P.** · **01-06-09, 05:15 PM**

Looking forward to your build!

**ISLAND1000** · **01-06-09, 09:33 PM**

OK,let me see if I got this right. The RL-P18 cleared customs, you've got all that great looking hardware from PE, everything goes into a 520 liter enclosure, uhmmmm . . . . . does anybody else in London know what you are planning? Have you notified Scotland yard and the people at "Big Ben" ? Are you aware that when the RL-P18 is loaded with 2500 watts it will pressurize the London Fog and that the fog will be hermetically dissipated??!! And what about the Thames River? When was the last time it ran backwards?? Are you ready to wreak that kind of havoc . . . . are you Bunky?? LOL Say YES I AM!!!

**Sonnie** · **01-06-09, 11:30 PM**

You could design it to be the local foghorn...

Looking forward to the build...

**Ukwarrior** · **01-07-09, 08:37 AM**

Island1000, as of this historical day, YES I AM!

Oh! What could this 50lb package be?

I am absolutely amazed by the size of the driver. It's awesome!

I have access to a workshop starting tomorrow. I'm not sure which days I'll be able to get down there but I'm going to organize some sort of schedule so that this can be done.

Ed.

**ISLAND1000** · **01-07-09, 09:16 AM**

OOOOOooooo . . . . . Momma!

I like that personalized signature next to the logo. It's too bad when you get a special piece of equipment shipped all the way across one of the major oceans that you can't keep the entire working frame, magnet, and cone out in the open where everyone can see and marvel at it's existence. But I guess having your ears being blown clean off your head at high volume by one of the most powerful drivers in the world is compensation of some kind.

**Bent** · **01-07-09, 11:24 PM**

I guess you could always buy two of them, and mount one backwards out of phase.
I didn't with my dual 15"'s though.

**ISLAND1000** · **01-07-09, 11:29 PM**

Wow! Look at that! TWO RL-P 15s. Nice looking piece of sonic furniture. But I just KNOW you don't play that huge cab while you've got the fish bowl that close.

**Bent** · **01-07-09, 11:34 PM**

I laugh every time someone mentions the fish.
Truth be told, there is only one fish in that aquarium, and it lives in another room now.

My subwoofer has been silent since the end of November. My Adire ADA 1200 crapped on me, and is being repaired. I hope to have it back by the end of Jan, so it can sing again.

**ISLAND1000** · **01-08-09, 12:13 AM**

I feel your pain brother . . . . but I'm sure the fish is relaxed.

**atledreier** · **01-08-09, 12:55 AM**

I sorta wish I could display my tubes like that. Mine plays best in the rear of the room, and sit behind the curtain that hide the projector and acoustic treatments. makes the room look innocent until the big bang, though. Got a few pretty surprised yelps from visitors when the first buffeting of the 'Serenity' reentrysequence....

**thewire** · **01-09-09, 01:07 PM**

Quote:

Bent wrote:

I guess you could always buy two of them, and mount one backwards out of phase.
I didn't with my dual 15"'s though.

Yeah.. it's a good thing fish don't have emotions or that fish would be

Nice looking subwoofer.

**Ukwarrior** · **01-15-09, 01:22 PM**

Update : Building should commence early next week; I'm finalizing my designs. However, I've run into a little problem; I've got access to plenty of 10 inch PVC pipe and I can create a nice port flare using the CNC router through the front baffle which will be two sheets of MDF, .75 inch for the front and 1 inch for the sheet to which the driver is mounted. However, using WinIsd, I get very large figures for the port length for a 10" port at 15hz - longer than any of the enclosures external dimensions if 10 inches is added to the length to ensure the port is at least its own diameter away from any walls.

To give you some idea, a 15hz tune with 10" pipe gives a length of 41 inches for the port (both ends flared) and tuned to 17hz 31 inches. A 19hz tune gives 23 inches which is manageable but defeats the purpose of building such a large enclosure.

It's hard and expensive to find 8 inch pvc here, which I didn't count on! I'll search around but it's not looking good. Perhaps a higher tune would be in order, but then I question the point of doing so in a box which is clearly capable of more.

Thoughts please?

Ed.

**ISLAND1000** · **01-15-09, 01:42 PM**

Your entire project philosophy is to get as low as low can go with the RL-P18. (Any) compromise because of unavailable cabinet parts is unacceptable. That is NOT the DIY way of doing things. Consider yourself punished.

**Ukwarrior** · **01-15-09, 01:44 PM**

I suspected as much.
Whatever it takes, I'll find some 8 inch pvc.
Ed.

**ISLAND1000** · **01-15-09, 01:58 PM**

Either that or design the enclosure dimensions around the driver AND the available longer 10" PVC. I'm thinking you could sonically operate the sub with less than the desired space between the end of the port and a box panel . . . . 10 inches seems like a lot of space and I've never heard from anybody about what happens (in performance terms) if the distance from the end of the port doesn't equal (less than) it's diameter.
The thing is this . . . . I can't remember anyone actually using 10" PVC for their port. It sounds HUGE!! I'd be proud if YOU were the first person to actually have a 10" diameter port!!!

**Ukwarrior** · **01-15-09, 02:14 PM**

Well, there's a first time for everything, so I might just give it a try!
I'm waiting for an email from someone who may (or may not) be able to source some 8 inch pipe for me.
10 inch pipe is massive, and I doubt I'd have any problems with port noise! I could potentially make the enclosure forward firing but downward or upward ported - that would give me the space I need to install such a large pipe. We'll see.
Ed.

**Ricci** · **01-15-09, 03:59 PM**

I've got 10" sonotube in my ported XXX and it is a very massive port. 10" PVC pipe ftw. Alternatively you could try dual 6" ports.

**Ukwarrior** · **01-16-09, 10:42 AM**

Good news,
I've got 2.5m of 8 inch ID PVC ducting pipe waiting for me at the workshop!
Ed.

Update:

Port cut to size, I'm currently creating the design on CAD (Cobalt v8) so that it can be converted into a .dxf file for the cnc router.

**Ukwarrior** · **01-20-09, 02:10 PM**

**ISLAND1000** · **01-20-09, 07:39 PM**

Quote:

Ricci wrote:

I've got 10" sonotube in my ported XXX and it is a very massive port. 10" PVC pipe ftw.

OOps, I forgot. But your port has that thinga magig in it so you can't see all the way to the end of the port . . . . can you? An open 10" port has that "I can hide it in here" quality that impresses me.
But who can forget that beautiful 25 Cu, Ft. Vented cab that Funky Waves constructed for you. That is one of my all time favorite projects. I didn't talk about it much on here cause I was jealous. Still am.

**Ukwarrior** · **01-21-09, 01:17 PM**

I've spent a few more hours battling with cobalt, I'm hoping that if I can finish these CAD files tomorrow afternoon then I can let the CNC router get to work. It takes about 15 minutes a side, so there are 12 sheets to be cut + one sheet for the front grille. So I may have the basic box assembled by the weekend.
Ed.

As you can see - I've gone with ellipse shaped brace cutouts and a slot-fit design which, if accurately cut, should fit together beautifully and provide a nice bit of strength to the enclosure.

Is there any need for triangular braces in each corner (small triangles of hardwood) for added strength or is that a little unnecessary?

**Mike P.** · **01-21-09, 03:14 PM**

No need for triangular braces with your design.

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