Hi, I'm just about to start my second subwoofer project.
I'd like to try a tube this time.
I've forund a supplier of cardboard/particle board tubes but I'm not sure what to order.
Is there a minimun wall thickness required for a tube of 450mm diametre?
Also is internal bracing needed with a tube?
My plan is to build a pair of 450mm tubes 750mm in length, each with a pair of 65mm pvc ports and a single 12" Monolith driver.
Driver specs are here http://www.bkelec.com/HiFi/drive_units/bsb/monolith_du.htm
Rich.
I'd like to try a tube this time.
I've forund a supplier of cardboard/particle board tubes but I'm not sure what to order.
Is there a minimun wall thickness required for a tube of 450mm diametre?
Also is internal bracing needed with a tube?
My plan is to build a pair of 450mm tubes 750mm in length, each with a pair of 65mm pvc ports and a single 12" Monolith driver.
Driver specs are here http://www.bkelec.com/HiFi/drive_units/bsb/monolith_du.htm
Rich.
Colin said:
Thanks.
Uk supplier is
http://www.essextubes.com/index.php?page=industrial
but they have yet to confirm delivery cost.
Thanks for that. Re your query about wall thickness - I have a set of cardboard tubes, 150mm diameter with 10mm wall thickness and these are very rigid. For the sort of use your talking about, I'd have thought 10 - 15mm would be fine.
I'll contact Essex and see if they deal with any builder's merchants nearby.
I'll contact Essex and see if they deal with any builder's merchants nearby.
Tube strength
These cardboard tubes are used to mold concrete columns and are very strong. The forces are evenly distributed all the way around the tube. If you were building a sealed tube you would have more trouble with your end caps then the tube. My tube sub is like the Bose acoustic wave cannon only it's 16" diameter and I used 2 18" woofers in a face to face push pull arrangement 3' into a 12' pipe. Total cost not including the amp was under $250US and it is the most articulate & deep sub I have ever heard.
These cardboard tubes are used to mold concrete columns and are very strong. The forces are evenly distributed all the way around the tube. If you were building a sealed tube you would have more trouble with your end caps then the tube. My tube sub is like the Bose acoustic wave cannon only it's 16" diameter and I used 2 18" woofers in a face to face push pull arrangement 3' into a 12' pipe. Total cost not including the amp was under $250US and it is the most articulate & deep sub I have ever heard.
The 18" is the outside measurement and the back side was just a hair bigger than the tube. I made 2" slits all around the sonotube and forced it onto the back side then sealed it with something similar to dynamat.
I am building a new one and will use Mach5 MJ18's this time, they will have greater Xmax and should have less surround noise at high output.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I am building a new one and will use Mach5 MJ18's this time, they will have greater Xmax and should have less surround noise at high output.
Sorry about the picture quality, My wife has the camera in Monterey and I had to use my cell phone.
Here is my theater. The sub is in the stage. I still have some finish work to do after I build the new one.
Here is my theater. The sub is in the stage. I still have some finish work to do after I build the new one.
An externally hosted image should be here but it was not working when we last tested it.
Both ends are open and with the drivers 1/4 in from one end the 2 outputs are in phase. If you keep our crossover point low enough, below 40-50Hz, it should work very well behind your couch. The woofer only took about 2 hours to build, the stage took the rest of the day and still isn't finished.
You can see in the pic with the outside wiring I used long threaded rod to bolt the woofers together. Then used I-bolts in the tubes to pull it all together. This made it much easier to handle the woofers after they were secured to each other.
You can see in the pic with the outside wiring I used long threaded rod to bolt the woofers together. Then used I-bolts in the tubes to pull it all together. This made it much easier to handle the woofers after they were secured to each other.
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