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RL-P18 meets the "DOH! button"

73K views 341 replies 45 participants last post by  Scott Simonian 
#1 ·




Good lord... what have I done?!





Suffice it to say I'm totally out of control with Google Sketchup. I'm not done yet and not really happy with the braces, so this is definitely a "work in progress".


On the bright side, no trees were harmed in the making of this drawing!



Regarding the box, it's 26H x 30D x49W. Target net volume 17 cu ft, 14.5 Hz tune. Port I.D. is around 8.375". It's a bit long at 35.25", but that does allow it to terminate nicely in the third brace.


Bradley
 
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#253 ·
I think a little of both... sweet and full of ****.



The avatar pic is not me. It's from the "Worst Job Ever" video . One of my favorites.



Sadly, I don't have enough hair left these days to qualify for the Gene Wilder/Einstein type... but in my *cough* "formative years" that was a frequently heard remark. Smeagle on the other hand... well... yeah... that's about exactly right!
 
#254 ·
Wow..I remember seeing that vid ages ago. I completely forgot about it. Funny as hell especially the f-ing f-ing f**kburger part.


BTW what was the OD of your port? I ordered a 8" sono for my port but was wondering what the OD was. I figure the sono is probably 1/8" thick? I am thinking about buying one of these bellmouths instead of routing the port flares to save some trouble and buying a 1.5" roundover.


Here's the site:
http://www.spiralfittings.net/standard%20bellmouth.htm


I am looking at the 9" which flares with a 2" roundover to 15". The ID is -1/8" = 8 7/8". Same with the 8"...ID = 7 7/8". If I do the 9" i can mold the inside of this housing to the outside of the sono maybe and bondo it to smooth the step with reinforcements on the outside. Just one possibility.
 
#256 ·

Quote:
Originally Posted by Avus_M3 /forum/post/12342562


BTW what was the OD of your port? I ordered a 8" sono for my port but was wondering what the OD was. I figure the sono is probably 1/8" thick? I am thinking about buying one of these bellmouths instead of routing the port flares to save some trouble and buying a 1.5" roundover.

The tubing I have is roughly 8 5/8" OD and a little over 8 3/8 ID. The wall is a little less than 1/8 thick. Genuine Sonotube brand will be thicker and have a smaller OD and ID, based on what I examined at the local Whitecap store. There's no real easy answer to doing to the port flares. Either way you have to join the straight tube part to the actual flare in some kind of seamless fashion. If your flare is made of MDF, you can just cut the flare circle to the appropriate size to match the tubing, then use some bondo to smooth over the edge where the two pieces join. If you use bell mouths, you also have to join/integrate them with the outer panel and the inner brace piece (if you flare both ends). I guess the real trick is getting tubing that matches the size of the bell mouth flare and figuring out how to join them together.


You'll need a router to cut your circles anyway, so maybe one of those 1.5" radius corner rounding bits for $60 from MLCS would be a good option. You have to go slow with it and do multiple passes, increasing the bit depth each time, but it comes out pretty nice in the end.
 
#257 ·

Quote:
Originally Posted by tatanka01 /forum/post/12342884


Just curious... are you going to sand that bondo or let "wind erosion" take care of the rough spots?

I sanded the bondo down before shooting it with the black spray paint. Not PERFECT but pretty smooth now.
 
#258 ·
Made some more progress tonight. Lined the box with polyfil, drilled holes for driver and terminals, and finally got the top panel on. Port outlet is looking good after shooting it with some of the bed liner spray.





 
#259 ·
You have any bass traps in your room btp? You will soon be in the realm of getting the bends like a diver!
 
#260 ·
Brad, the box looks stuffed. You sure it's not too much. You don't have to have any if the response looks good...at least on Unibox.
 
#261 ·
It's really not as stuffed as it looks. Honest.
I set out to just line the walls but there is some polyfil on the big tube in the middle, so that contributes to the "stuffed" look. I used much less fill this time than on the first one (which has already been "de-stuffed"). If I had to guess, I'd say there's about 3 pounds of polyfil in there right now which is around 3 ounces per cubic foot.


No bass traps in the room... yet.


So tired now. I was up until 2 AM working on the dang thing.


Edit: What I'm really curious about is the tune on this second box. Will it be exactly the same as the first one? Higher? Lower? I already have a feeling I will wind up swapping the drivers between the two cabinets (out of paranoia) just to see if that makes any difference in the tune of either. How's THAT for neurotic?
 
#262 ·

Quote:
Originally Posted by vitod /forum/post/12348410


Brad, the box looks stuffed. You sure it's not too much. You don't have to have any if the response looks good...at least on Unibox.

I was about to ask that because from what I remember he removed most of it from the last box.



BTW why so many alternators???
 
#263 ·
Because they were there?
Just grabbed whatever I could find that was heavy to throw on the top for good measure, to press the panel onto the underlying network of bracing. I knew at least a few people would get a good laugh out it... 3 dead VW alternators and one dead OEM Audi battery.
 
#267 ·
Well, thanks to several days of pouring rain here in the Pacific Northwest, my garage is taking on a bunch of water. The GOOD NEWS is that the second subwoofer is resting on a pallet located on somewhat of a high spot where the water hasn't really accumulated. Some of my scrap MDF and other things in the garage have gotten wet, but no major losses. I just need to finish up some caulking and polyfil inside the box now that the top panel is on. Then sand all the seams down and router the external edges. Then it will be ready for paint and/or the driver to be installed. But with this water problem I'm really itching to move it into the house, so the paint might have to wait a bit longer. *sigh*
 
#268 ·
Quick update: the second box is just about ready for paint now. All the glue seams are sanded smooth and edges have been rounded. But I may not paint it right away. Need to give that some more thought as I wanted to paint both subs at the same time and moving them... well... it's just a serious P.I.T.A.! I think I better invest in a good furniture dolly (AKA "hand truck").


I'll post some more pictures tomorrow.
 
#269 ·
I really like the layout of your subs. They really look great. Good build. I really like the braces and that is how I wanted to lay them out. I think I am going to go that way.


2 of them ought to give you some serious output. Hopefully you finish soon. Good luck.
 
#270 ·
Thanks, Robert. It was a LOT of work but I'm pleased with the results. You really don't know what you're missing until you get some serious "subwoofage" in place!



Without further adieu, here are some pictures of the TERRIBLE TWINS.
OK, so they're not quite as "terrible" or enormous as Scott's, but they definitely rock the house with incredible authority.


And before anyone asks... I plan to paint them both at the same time at a date yet to be determined. I will probably paint them (with the bedliner stuff using a roller) right where they sit as the subs are rather difficult to move. I'll just use plastic to cover the projection screen and floor and anything else nearby.







 
#272 ·
I figure if the RL-P18 is sturdy enough to support a large chihuahua...




... then it should hold up well against my almost-5-year-old son.



I actually do not have any plans to cover the drivers. Why? I guess I'm just lazy.
The aluminum cone and rubber surround of the RL-P18 seem pretty tough. The "cone" is actually spherical in shape (not conical). Imagine a slice being taken off a very large ball.


Man... now that they are both in place... I am really itching to paint the cabinets!
 
#274 ·
They make your screen look small



I highly advise you NOT to paint them in the house!!! I say this because I bought some of that DiY bedliner stuff and used it on my old truck a few years ago. That stuff is crazy high in VOC's. It will fry your mind if you paint that inside. I did my bed halfway in the garage and halfway outside (out of the sun) and it was pretty nasty stuff.
 
#275 ·
You're not the only one to say that! Oh, what a problem to have... your 8 foot wide screen suddenly seeming small!



I'll keep that in mind. If I do paint them in the house (split level "daylight basement") I'll open up all the windows and the sliding door down here and get some fans going. So far the Duplicolor bedliner spray doesn't seem all that noxious.


I brought my PC downstairs and fired up Room EQ Wizard. First thing I did is test the resonant frequency of the second sub. It came out at 13.2 Hz compared to about 13.0 Hz for the first sub. I used slightly less stuffing and the driver isn't broken in, so that seems about right to me. At least they are consistent.


I've got some more SPL graphs I'll post soon. One thing I can say is that the "twins" are capable of 120 dB at 13 Hz in-room (mic at 2 meters). Good god, my neighbors must really hate me by now. I didn't realize it was already 11:30 PM. Oops!



As the room is wreaking havoc with the response at 43 Hz, I'm not sure I will leave the subs under the screen. Lots of experimentation (AKA "trial and error") to be done here, that's for sure.
 
#276 ·
Alright! My man!



Those look fierce! Very cool, indeed. Funny that you mention some problems in the 40's with your setup. Not sure how much of my build thread you went through but I had (have?) the same problem. I had to relocate my subs and alter the speaker/sub XO. A simple change of 80hz to 60hz made the transition much smoother. Although with time I have noticed that my subs easily outpace my mains. An serious upgrade is in the works for me. Also, have been looking at projectors and it looks like I should skip 1080p for a little while and go with the Panny AX200U. Not a bad projector at all.



The screen I want costs as much as the projector though. Know of any affordable but good looking acoustically transparent screens, Bradley?



Give us some updated measurements with them in the place they are now and do some relocating if needed. Lets contrast and compare.



Good work, bass brother.
 
#277 ·

Quote:
Originally Posted by Scott Simonian /forum/post/12454510


Also, have been looking at projectors and it looks like I should skip 1080p for a little while and go with the Panny AX200U. Not a bad projector at all.

Ditto...same model as well.

Quote:
Originally Posted by Scott Simonian /forum/post/12454510


The screen I want costs as much as the projector though. Know of any affordable but good looking acoustically transparent screens, Bradley?

There are some DiY A/T screens I have seen on here with good results. Sorry, no link handy.

Quote:
Originally Posted by Scott Simonian /forum/post/12454510


Give us some updated measurements with them in the place they are now and do some relocating if needed. Lets contrast and compare.

Sounds like "Show me yours and I will show you mine" huh Scotty?? J/k


Going to be around for New Years? It looks like I will be in Clovis for it.



As for the bedliner maybe the spray is better. Mine came in a jug that I had to roll on. Nasty ****
 
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