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Sonosub + RL-p15 - Design confirmation

post #1 of 401
Thread Starter 
I've pretty much nailed my sonosub design. Can you experts please greenlight the attached design before I start the production? I'm hopefully going to make two of these babies and power them with a EP2500 (or maybe two bridged EP2500s?).

Top and bottom is 3x22 m MDF.
Net volume: 260-265 liters
Port length: 75 cm

Thanks a lot :-)
LL
LL
post #2 of 401
Looks good to me. You'll only need one EP2500 for two of these subs, btw.
post #3 of 401
nice, classic LLT design. I've got the same setup - 2 20" cylinders each with 265L, RL-p15, tune to ~16hz. 1 EP2500 is definitely enough to drive these things though, no need for two.

Mine was the same design that others have used, with minor variations:
2 layers of mdf, driver not recessed (who's gonna see it down there anyway?)
legs are 5" 2x4 pieces with rounded edges, I like the beefier look
12" speaker grill for port cover
black spray on bedliner instead of the gloss

good luck!
post #4 of 401
Looks good.
I wouldnt bother recessing the driver in this situation either...for a front firing sub its just a no brainer IMO.
post #5 of 401
"Recessing" the driver for something like a sonosub is extremely simple though. All he'd have to do is cut the hole out on the end cap piece a bit bigger. I think it makes sense because otherwise, you'd want to make the legs a bit taller. I dunno about you, but I kind of like having my driver "built in" a bit.
post #6 of 401
Thread Starter 
Quote:
Originally Posted by Willd View Post

Looks good to me. You'll only need one EP2500 for two of these subs, btw.

Your sonosub thread was my inspiration so I guess it's only natural that you like it

If there's ANYTHING you would have done different, however, now is the time to tell me! And I'll keep "only one EP2500" in mind...
post #7 of 401
I would have made the top endcap assembly thicker. I only used two layers of 3/4" MDF, but 3 should be the minimum. I'd also line the bottom side of the top endcap assembly with whatever you line the walls with.

Other than that, I don't think so. I can't find a ruler right now, but I'll answer your PM after I get back from class.
post #8 of 401
Thread Starter 
Quote:
Originally Posted by Willd View Post

I would have made the top endcap assembly thicker. I only used two layers of 3/4" MDF, but 3 should be the minimum. I'd also line the bottom side of the top endcap assembly with whatever you line the walls with.

OK, I was going to use 3 layers of 22 mm MDF so I guess it will do. One of the reasons I go so thick is to have more are to fasten the end caps better to the tube, which leads me to another thing that I've forgotten to ask people about: What kind of glue did you use to attach the caps to the tube?

Quote:
Originally Posted by Willd View Post

Other than that, I don't think so. I can't find a ruler right now, but I'll answer your PM after I get back from class.

Just to make things absolutely clear for all you dirty minded people out there: I was asking him about the thickness of the TUBE WALLS in the PM...
post #9 of 401
If you cut your endcaps the right size, you really don't need anything to attach them to the tube with. You don't want to use wood glue for sure. Personally, I ran a bead of liquid nails along the interior seam on the top and bottom cap of my sonosub. The fit was tight enough that it really wasn't necessary, but I felt better about doing it Good luck on your project!
post #10 of 401
Quote:
Originally Posted by RuneW View Post

OK, I was going to use 3 layers of 22 mm MDF so I guess it will do. One of the reasons I go so thick is to have more are to fasten the end caps better to the tube, which leads me to another thing that I've forgotten to ask people about: What kind of glue did you use to attach the caps to the tube?

If you have a super snug fit, probably nothing. If you want a little more security, you can go with Silicone caulking, just to make sure you have it air tight.

Liquid Nails is going to be your next step up, a little more permanent, has a stronger "gap filling" ability.

Epoxy is going to be the ultimate in permanent and gap filling. It's harder to work with, but there are lots of new applicators now I haven't even tried.

Kevin
post #11 of 401
I used liquid nails as well.
post #12 of 401
Thread Starter 
Quote:
Originally Posted by parboy View Post

If you cut your endcaps the right size, you really don't need anything to attach them to the tube with.

Quote:
Originally Posted by newroswell View Post

If you have a super snug fit, probably nothing. If you want a little more security, you can go with Silicone caulking, just to make sure you have it air tight.

Yes, yes, I can hear you guys

But it must involve a little bit of luck to get the end caps that tight, doesn't it? I myself cannot imagine how you could actually measure that precise. Well, a few test runs with the router would help, I guess...

Anyway, I would like to seal the end caps with something, not only to make them sit in place, but also to make it airtight (also after a few years).

Thanks for the tips! I've ordered the tubes today and will probably talk a little to the manufacturer about which glues they would recommend.

Just a sidetrack: The guy at the factory said that they had two types of tubes: Waxed and non-waxed. He strongly recommended the non waxed type for speaker building because of "resonances". I cannot imagine what kind of resonaces this might be. Then again, I can't be absolutely sure of what he really said because this information came via a guy at the store (a norwegian version of Home Depot or something). The guy at the store actually said that the waxed versions was no good because of renaissance problems. Obviously not a speaker expert or a historian...
post #13 of 401
Quote:


But it must involve a little bit of luck to get the end caps that tight, doesn't it? I myself cannot imagine how you could actually measure that precise. Well, a few test runs with the router would help, I guess...

The safest thing to do is be on the safe side and make your cuts ever so slightly larger than they should be, and sand them down to fit, or depending on how precise/imprecise your cuts are, they could turn out perfect.




The waxed version sounds like the Rain Guard Sonotube we have over here. Thats the first I've ever heard of it being worse than "non-waxed" for sub building.
post #14 of 401
Quote:
Originally Posted by RuneW View Post

Yes, yes, I can hear you guys

But it must involve a little bit of luck to get the end caps that tight, doesn't it? I myself cannot imagine how you could actually measure that precise. Well, a few test runs with the router would help, I guess...

If you haven't cut circles with a router (go with a plunge model) on a circle jig, you're going to like it. You can use a model that isn't a plunge, but if you're buying one, you're first router should be a plunge.

Like Will said, go with a setting that is too large, and sneak up on it in (hopefully) small increments until you get to the point where you're about 2mm too big. Put a chamfer or round-over on the edge that goes into the tube first.

Once I had all my caps glued and cut (yes I glued my cap layers together while square, then cut circles), I thined down some polyurethane with mineral spirits and sealed the MDF. That keeps the edges perfect, even after lots of insertions/removals (assuming you're going with a dry fit).

I would guess the waxed tubes are better for this because the cardboard is then sealed on the inside. I'm new to speaker building, but generally in woodworking, when you have one side that is sealed, you want to go ahead and seal the other as well. Since we're dealing with mostly enclosed volumes here, this isn't so important though.

The 3M spray adhesive stuck great to the wax surface when I put the batting in. My ports are also wax coated cardboard tube and enamel paint just sprayed down the tube on a warm day worked perfect also.
post #15 of 401
Quote:


The 3M spray adhesive stuck great to the wax surface when I put the batting in. My ports are also wax coated cardboard tube and enamel paint just sprayed down the tube on a warm day worked perfect also.

Aye. I used some 3M Super 77 and it stuck very well to my Rain Guard was coated Sonotube.
post #16 of 401
ALso, even if the end caps' insides don't fit exact, the top cap will seal the unit. Furthermore there is no way for the caps to pop out. The bottom cap has the weight of the sub itself holding it in, and the top cap has gravity holding it down.
post #17 of 401
Quote:
Originally Posted by Favelle View Post

ALso, even if the end caps' insides don't fit exact, the top cap will seal the unit. Furthermore there is no way for the caps to pop out. The bottom cap has the weight of the sub itself holding it in, and the top cap has gravity holding it down.

oh, wait, wait. Let's define "don't fit exactly". If those plugs are sloppy and only sealed by gravity, you just lost your tuning, not to mention it's going to rattle. Probably won't jump off, but that's gotta sound like crap.

If the plugs are nice and round, but not super-snug, use Liquid Nails. If you cut the plugs freehand with a Jigsaw, then you need to go epoxy and get those plugs air tight, so that the only air movement is what you get through the port. Nothing should be lose.
post #18 of 401
These thing are so big , they're turning into moblie IB's !
post #19 of 401
If those plugs are sloppy and only sealed by gravity, you just lost your tuning,

How would you lose tuning if the end cap seals everything??? Its not like air is escaping anywhere but the port...the end cap is LARGER than the diameter of the tube, so it creates a perfect seal. The inner pieces are there to hold the port tube in place and something to screw the driver to.
post #20 of 401
I just think building a sonosub the relies on gravity to hold it together is a bad idea. I don't believe you are going to have an end cap that "seals everything" just sitting there.

It's not hard to seal those plugs. I know gravity is free, but enough LN to do this right is like $6 where I live.
post #21 of 401
I know this is a bit old but I wrapped mine in felt and left about 2" on both ends then tucked the felt inside the tube. I had to do 1/4 round over on both my end caps so they would go in. Worked great and if I ever need to get something out of the tube ... like a G.I. Joe it will be pretty easy.
post #22 of 401
Quote:
I just think building a sonosub the relies on gravity to hold it together is a bad idea. I don't believe you are going to have an end cap that "seals everything" just sitting there.

I do Very tight tolerances.
post #23 of 401
I'm not a speaker expert but there is basic engineering issues with this.

Er, it's not "gravity" it what's called an interference fit. You could fiddle with measuring the coefficient of friction and do some analysis on the forces inside the pressure vessel to see if it would deform in the elastic range but given peoples experience here there is evidence of that not occuring. Any further methods of sealing is just over engineering. There is always a better way to do it, but an engineering goal is fit for purpose.
post #24 of 401
Quote:
Originally Posted by Stitz View Post

nice, classic LLT design. I've got the same setup - 2 20" cylinders each with 265L, RL-p15, tune to ~16hz. 1 EP2500 is definitely enough to drive these things though, no need for two.

Mine was the same design that others have used, with minor variations:
2 layers of mdf, driver not recessed (who's gonna see it down there anyway?)
legs are 5" 2x4 pieces with rounded edges, I like the beefier look
12" speaker grill for port cover
black spray on bedliner instead of the gloss

good luck!

you need to post some pics fool!!
post #25 of 401
Quote:
Er, it's not "gravity" it what's called an interference fit.

Exactly! because of a little issue in figuring out the sock, one of my caps was rather loose compared to the interference fit and thus became a gravity fit Well! put it to you this way> Think of a huge 30 pound corn kernel popping off when some heavy bass comes along.
post #26 of 401
Thread Starter 
Quote:
Originally Posted by ssabripo View Post

you need to post some pics fool!!

I'm sorry, was this meant for me or for Stitz?
post #27 of 401
Quote:
Originally Posted by RuneW View Post

I'm sorry, was this meant for me or for Stitz?

you!

the more pics, the merrier.......we all love following a fellow DIYer when he/she is going thru their project!
post #28 of 401
Thread Starter 
Quote:
Originally Posted by ssabripo View Post

you!

the more pics, the merrier.......we all love following a fellow DIYer when he/she is going thru their project!

OK. Sure, here: Runes Sonosub Project (enjoy the norwegian texts :-)

OK, I'll post a few pics with English texts when the kids are in bed

I'll keep you updated, but I must warn you - it will be a slow progress as I have 3 small kids crawling all over as well as a house renovation project...

AND I cannot get TC Sounds to mail me back. I've ordered a couple of TC-2000 SVC 15s, but they won't reply to my emails. So - I have no idea when/if I get the drivers...
post #29 of 401
Quote:
AND I cannot get TC Sounds to mail me back. I've ordered a couple of TC-2000 SVC 15s, but they won't reply to my emails. So - I have no idea when/if I get the drivers...

Well that's a bummer.
post #30 of 401
Thread Starter 
Quote:
Originally Posted by steve nn View Post

Well that's a bummer.

Yeah. I guess it has something to do with me living in Norway or something. The strange thing is that the PayPal transaction went through without any problems, Norway or no Norway...
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