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Discussion Starter · #1 · (Edited)
My SS RL-p15 build *or maybe 18?*

I'm just starting out this project, but might as well start a thread on it now. I've more or less decided to go with the Rl-p15, unless any of you would object to that and give me a better driver in that price range. I have a long term plan with this. I'm building a house sometime in the next few years, and it will have a dedicated home theater. So the plan is to have 2 or most likely 4 RL-p15s by then and do a 'proper' build. I need some experience first, and will probably end up doing a few different designs. For now I'm starting off light with one driver and an EP-2500 to drive it.

I've looked at 'Jerm357's build here, and that seems like a very good place to start. It should fit my room nicely in one of the rear corners, and if it works I'll put another one somewhere.

I currently have an SVS PB12plus/2 that I'm happy with, except it feels a little 'slow' sometimes. Might be room or placement, but I can't seem to make it work no matter where I put it.

So I'm thinking RL-p15 in about 250l effective volume with around 15Hz tune. I would like to keep overall dimensions (outside) within 60cm by 120cm, for materials cost.

Any thoughts on how the DIY will compare to the PB12+/2?

Anything I should do different?
Will I need anything besides the box, driver and amp? I have a BFD.
As far as i can gather from the net, the EP-2500 can handle 220V AC, right? Are there differenet versions or does it have a switch? Do I want the 2ohm or the 4ohm version of the driver?

I have little woodworking skills, but I'm willing and eager to learn. I've made some room treatments before, corner traps and panels. Am I crazy to start on womething this big?
 

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Sounds good. Just in case you needed more assurance, know that 260 liters and a 6" diameter port that is 30" long (or a design very close to that) has been built by a LOT of people with great results time after time.
 

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Discussion Starter · #6 · (Edited)
Still haven't ordered the stuff. I'm torn between the 15 and the 18, and also between LLT and IB. If I take the plunge and sell my SVS PB12+/2 I can easily get the amp and at least two drivers. There is not much difference in price between the 15 and 18, but with the 18 I'll probably never build a proper LLT for them, as they would be prohibitively large.
However, if I get the two 15s, it's likely that I will be able to get another two pretty soon, and then do a 4:1 manifold. How would a 4 x 15 IB work compared to a 2 x 18? Also, two 15s can fit in my room in LLT config.

I'm planning an EP2500 still.

I'm also loving my SVS, and I'm a little worried that if i sell it I won't be able to bring that performance back, and will be chasing rainbows forever. Sonnie, if you ever ran with a single +/2, can you honestly say you'd never go back? Or am i just being conservative here, and need to shut up and just do it? I'm currently running my +/2 in 20Hz tune. 16Hz tune give me a large bump below 20 that I can't equalize. Will this be a problem for a LLT?
 

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Discussion Starter · #8 ·
I've downloaded WinISD pro beta, and tried modeling the RL-p15 in it. I used the 'usual' 260l, 14Hz tune, and it didn't look good at all. Excursion was way over X-max, post velocity was in the 50s, group delay peaked at around 70ms... What am I doing wrong?
 

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Discussion Starter · #12 ·
It would just be too big. A single PB12+/2 pressurize the room nicely, so I think I'll be all right with dual 15s. When I move to a bigger room I can just get another 2 15s. So how big would a p18 LLT have to be? Shame on you, man.. you've planted a seed.... :p
 

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Discussion Starter · #13 ·
Just got a reply from Mike at Soundsplinter. He's cooking up an invoice fro me right now.... I'm excited already, and I know it'll be a few weeks before I'll have the drivers here so I can start building. I'll use the time to get some tools and do some testruns with the router, I think. Plus get all the bits and pieces I'm gonna need, like ports, flares, terminals, cables for the amp and so on.

Since I'll be without sub for a while, I've been considering trying the BFD on my mains, just for kicks. I'm pretty sure it'll sound ****, but it'll keep me busy. :p
 

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Discussion Starter · #14 · (Edited)
Got the invoice, and Mike will ship the drivers as soon as my bank send him the money.
I've been learning sketchup tonight, just looking at some different enclosures. I initially thought to make it like a sonotube, only square. I like the small footprint. But then I though maybe have the boxes wide and low. If I do that the port will exit at the front baffle beside the driver. Any issue with that? What is the recommended distance from port to driver? Still the regular port diameter? Also, if I have a good internal flare, can I go less than one port diameter from the back wall of the box?

If I decide to go the 'tube' route, is this enough bracing?
I haven't made any cutouts yet. The driver will go in the bottom, the port out the top. I'm planning 1" MDF, maybe 3/4" for the braces. The top and bottom will be dual layer MDF, since they have no bracing. How much room do I need from the back of the magnet to the closest brace?

http://www.hometheatershack.com/photopost/data/500/medium/RL-p15_kasse.png
 

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Even if flared, you don't want any port opening close to a surface - port diameter as a minimum clearance is just that, a minimum clearance. If you go wide and low, let the port fire out one of the sides. That way you'll have plenty of room to play with for the port.

Not sure I follow the questioning in paragraph two correctly, but just so you know, sonosubs don't need any internal bracing.
 

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Discussion Starter · #16 · (Edited)
Yeah, I had originally thought that sonotubes were unavailable in my area, but it turns out there's a supplier 2 minutes from where I work, I can see it out the window. :whistling: So I've sent them an email asking for prices. They call them 'monotubes' though, but I guess that's just the brand they use. So I guess I'll be going for tubes after all. Sounds like a much easier build.

Edit: The tubes are very expensive, it turns out. :spend:The MDF required will be cheaper than a single tube. So I guess it's back to the drawing board... :scratchhead:

Edit2: Found a much cheaper supplier, so I think tubes is back in the game! :yay:
 

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I'm also loving my SVS, and I'm a little worried that if i sell it I won't be able to bring that performance back, and will be chasing rainbows forever. Sonnie, if you ever ran with a single +/2, can you honestly say you'd never go back? Or am i just being conservative here, and need to shut up and just do it? I'm currently running my +/2 in 20Hz tune. 16Hz tune give me a large bump below 20 that I can't equalize. Will this be a problem for a LLT?
I have always kept my SVS subs in the room. My Behemoth was a specific design for a specific purpose, which was to add a sub to the rear of the room. I had moved one of my PB12-Plus/2's to the rear and it balanced out my response very well. The Plus/2 was too big to leave back there with the little space I have, so I designed and built specifically for the space. The Behemoth added very good extension and increased max SPL considerably, not that I use the extra SPL during normal listening. Since all this I have sold my Plus/2's and replaced them with the PC-Ultra's. There is a remarkable difference in the response (no BFD needed any longer) and the overall sound has improved.
 

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Discussion Starter · #18 ·
Yeah, I'm also hoping that having twin subs will give me some options on placement. The BFD has two channels so I'll be able to equalize each differently if I need it. The single +/2 gave me the extension and SPL I needed, really, but I found it a little lacking in raw SQ. I hope to bring that back with the two RL-p15s idling in the background. I have some pretty decent fronts (Dali Euphonia MS4) and the matching center. Those has some of the best bass quality I've heard, so my subs need to perform to match my front row. The sonotubes will be (relatively) easy to move around, and I'll be able to experiment more with placement. I can't wait to get cracking!
 

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Discussion Starter · #19 ·
The sonosub program/calculator tells me my tube will have a resonating frequency of 59Hz, and recommend damping of the top plate. How much damping do I need? Is there a 'too much' scenario? I was thinking of doing acoustic panel, cut to fit the top around the port. I have 4" panels. Do I want one or two layers? Do I need to calculate the loss of volume from this damping? The wavelength of a 59Hz wave is much longer than what I can hope do damp effectively anyway, so.. Please explain why and how.
Also, damping the inside of the tube. I see most use a thin 'egg carton' type foam. What is the point of this? The foam will not damp anything at the passband of the subwoofer anyway.
 
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