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View Full Version : amature clam shell design



germandark
01-26-2009, 07:51 PM
okay here is my pos sketch up # 1

http://i11.photobucket.com/albums/a161/germandark/clamshell.jpg

each port has (rounded up) 85in^ of port area.

each is tuned to 36 hz. <<<< am I supposed to tune each port to the total desire tuning or what? I am working on trial and error.


each side is 8.125ft cubed.

______

My port area is a bit small, I know.

I would glass corners/etc. and use threaded rod for bracing. I was thinking of double baffle for the subs.

this is my first mock up...I am not too happy with it but I will keep on.

ALSO I plan on dc level 4 15's


questions & comments?

germandark
01-26-2009, 08:46 PM
ttt

Jeremy M
01-26-2009, 10:20 PM
looks identical to supergumby's....

rollinonD's
01-26-2009, 10:21 PM
I would try and tune a little lower within the 30-34hz range as thats where those subs are most comfortable at. Overall looks good and should thump.

germandark
01-26-2009, 10:22 PM
who is supergumby? think he/she would mind if I asked a few questions?

edit: that's the guy with the avalanche!....I was really impressed with his design, I tryed to base mine the same way but obviously smaller for my little ranger.

Jeremy M
01-26-2009, 11:15 PM
who is supergumby? think he/she would mind if I asked a few questions?

edit: that's the guy with the avalanche!....I was really impressed with his design, I tryed to base mine the same way but obviously smaller for my little ranger.

makes sense

germandark
01-27-2009, 11:14 PM
#2 here.

http://i11.photobucket.com/albums/a161/germandark/clamshell2.jpg

6.73ft cubed each side, 6.93 before guesstimated displacement.

99in^ of port area for each side, total of 198in^

effective port length is 24.5in so Ill just say 24in.

tuned to 35 hertz, actually 35 point something.

questions & comments?

18inchjeepin
01-27-2009, 11:17 PM
2 looks stronger, but sacrafice some box

would firing 2 subs into each other cause problems?

germandark
01-27-2009, 11:47 PM
2 looks stronger, but sacrafice some box

would firing 2 subs into each other cause problems?


both enclosures would be braced with glass, and threaded rod.

about the subs firing together...could cause and issue. I've seen people get 4 deep like that before and it sounded just fine. I wouldn't think cancellation would be too much of an issue, the dc level 4's have a bit over an inch of travel for xmax, if I remember correctly, so with the space between them I don't think their will be too much compression to cause cancellation. I could be wrong tho.

TnT_Sounds
01-28-2009, 03:25 AM
No problems with the subs firing like that.. it would only cancel if the subs are moving in OPPOSITE directions. They are moving the same direction and are all pressurizing the middle chamber at the same time. Being "in phase" is more important then the direction they are aiming, even if its at each other.

Looks great man. Although it does look like a 6th order quasi tuned bandpass

germandark
01-28-2009, 12:37 PM
ttt for suggestions.

TnT_Sounds
01-29-2009, 11:07 AM
Why 4 15's?

germandark
01-30-2009, 12:09 AM
I was favoring 8 12's originally, or 6. I am just planning right now.

DBBOOM
01-30-2009, 12:24 AM
Firing against each other doesnt hurt anything, it really just acts to load the subs. I have 4 15''s in a tunnel blowthrough 4th order bandpass. All four of mine sit squarely though, no flare, been told that it also raises the power handling ability of the sub. I have 2.5 cu ft for each sub and 10 cu ft in the front chamber. My port is tuned to 30hz, i have great response from around 30-65hz. And by having the rear chambers sealed it has a nice low end extension with a very accurate sound. Also, nice that i only had to cut a 14''x14'' hole for the port and not a huge hole in the back of the cab.

Supergumby5000
01-30-2009, 02:03 AM
the two inner subs (that arent angled) are going to fight against the port a wee bit, but it probably wont make an audible difference.

If you can, slant all four subs. It will help with that a little bit. Your setup pretty much has the sub IN the port.

Also, with that type of setup, im guessing your port length is as long as the end of the middle board? You may have taken this into account already, but that box design will treat the whole length (including those first subs) as port. if you havent taken that into account, tuning will come out much lower.

TnT_Sounds
01-30-2009, 04:03 AM
Thats about all that you'll get as far as interferance just cuz your subs in the rear will be even and the sound waves leaving a flat surface to going to that flare with the other 15's also pushing out that way.. My 6 12's are in a 4th order and it slams.. I have voltage problems tho so I dont play with it much.

germandark
01-30-2009, 01:00 PM
with the advice from all of you, I will revise my ideas. taking into account what supergumby said, Ill find the length of my port with the subs in account. would I have differnt port area that way tho? I think I will try to have al four angled now, and I may try a 6 12 setup.

thank you all.

I will post of with my next mock ups.

germandark
02-01-2009, 11:42 PM
here is mock up #3 it is very much like supergumby's. I followed his advice on taking the subs "out of the port." this gave me less air space but the subs will still be getting enough and each chamber is tuned to 32 hertz with 79in^ of port area. it is more a true clam shell now. I really like this design.

again it will all be braced with threaded rod and fiberglass.

http://i11.photobucket.com/albums/a161/germandark/clamshell3.jpg

questions & comments.

edit: after doing some other measurements, tuning maybe actually be around 30 hz. anyways its very low 30's

germandark
02-02-2009, 04:16 PM
before work bump

Lakota
02-02-2009, 04:24 PM
the two inner subs (that arent angled) are going to fight against the port a wee bit, but it probably wont make an audible difference.

If you can, slant all four subs. It will help with that a little bit. Your setup pretty much has the sub IN the port.

Also, with that type of setup, im guessing your port length is as long as the end of the middle board? You may have taken this into account already, but that box design will treat the whole length (including those first subs) as port. if you havent taken that into account, tuning will come out much lower.

What kind of #'s does your setup do? Looks interesting.

germandark
02-03-2009, 12:59 PM
Ttt

TnT_Sounds
02-03-2009, 01:37 PM
Hmm... Maybe, maybe not:confused: Are you sure thats enough air space for the subs?

germandark
02-03-2009, 01:59 PM
DC's specs say 3-4 cubes each...I have 3+ cubes for each sub.

TnT_Sounds
02-03-2009, 02:07 PM
Are you planning on double baffling? Or just all thread?

germandark
02-04-2009, 10:26 AM
the only parts that will be double are the baffles and the outter part of the port walls. not the inner divison for the port. the enclosure is built to max dimensions of the bed of the truck.

germandark
02-05-2009, 01:39 PM
bump for replies while I'm at school.

germandark
02-06-2009, 06:36 PM
ttt I will begin soon unless someone has some kind of dire knowledge, and recommends I don't build this enclosure.

germandark
02-07-2009, 08:11 PM
done deal. see it in the future.

TnT_Sounds
02-07-2009, 08:17 PM
Good luck