Large 16" PVC for Sonosub??? (1 Viewer)

[Joey_R]

I've got this piece of 16” PVC pipe that I procured with the intentions of building a sonosub. Here are the photos:

Photos are here.

This piece is currently 46” tall and weighs +/- 150 lbs. As you can see, it has a “bell coupling” on the bottom that is 17.5” in diameter. Ideally, I was thinking of building a bar-height cocktail table with a marble top that would sit behind my livingroom “sweetspot” for additional people. I fully expect the table will get lots of use. Otherwise, it will be a water heater in the corner. That would mean a Shiva/Dayton DVC 12” with bottom porting. The current gross volume is +/- 162 liters. Power by either PE 250 or a Crown Pro amp from my LFE channel. I do not have a terribly critical ear, just one that appreciates good bass. Room size is 21’ x 15’. Movies 80%/Music 20%.

1.How practical is it to use this piece of PVC pipe?
2.Should I abandon the PVC in favor of real sonotube?
3.Is it practical to think this could be a cocktail table considering vibration?
4.My research indicates this enclosure volume is fine for the 12” drivers I’m considering. Agree?
5.I’ve got an open mind, any thoughts?

Links work for now!

 

[Joey_R]

Links now working.

 

[TimForman]

Gonna have to be an awfully skinny port opening. Might be better to port out the other end although that would render it useless as a table.

 

[Joey_R]

Could I not use 4 inch port(s)? Granted, they may not be straight, but would still meet length specs. I was thinking of using a pair of 45 degree turns to shape them so they fit the interior of the tube better.

Seems as though I've read a general rule that ports need to be 3 inches off an enclosure wall, which would be a deal killer for me. If this is true, what is basis for the rule.

 

[TimForman]

OK, I'm confused. I'm assuming the speaker will be downfiring also which means you'll only have a support ring around 2 1/2" thick. Or are you having the speaker fire up into your table top?

 

[Joey_R]

Both driver and port would be in the bottom plate. Recall The bottom inside diameter of the tube is 17.5 inches, the top inside diameter is 16 inches. Is 17.5 inches insufficient for both a 12" driver AND a 4" port, or do I need more space between the two?

 

[Bob Huskison]

Looks to me like you're going to need more room, especially if the port is going to be flared.

 

[Justin Ward]

You could go with a sealed 15 inch driver.

 

[Joey_R]

You know, I hadn't even thought of a sealed enclosure because every other sonosub I looked at was ported. When I get home, I'll have to model a sealed enclosure with the Tempest or Dayton DVC 15".

 

[TimForman]

Sealed designs are great for music but you said you're mostly interested in movies and you like bass. That makes me think you'll be happier with a ported design. You just won't be able to use it as a table. It'll still look good with the bell shape and you should be able to put a nice finish on it.

 

[Joey_R]

I still havn't abandoned the bottom ported idea just yet. 12" + 4" = 16". I have 17.5". Or, I suppose I could go with two or three 3" ports, assuming it models correctly.

 

[Justin Ward]

This option would be kind of ugly but it might work:
A bunch of 2 inch(non-flared ports) arranged in a circle around the driver. You could probably fit 8 ports easily and this would be the equilivalent of 2-4inch ports? Are there any flaws with my reasoning?

And who says the ports have to be circular?

 

[Joey_R]

And who says the ports have to be circular?

No one, really. I'm just following the herd. :frowning:

 

[TimForman]

What material are you using to support all this inside the tube?

 

[Joey_R]

Assuming you are referring to the top/bottom plates, I was intending to use 2 x 3/4" standard MDF.

 

[TimForman]

That's going to make for awfully thin pieces in between the driver and the port. The way you're describing it your port will be flush against the edge of the driver. If you're using a 12" driver the basket edge could be 12 1/8" and if you use a flared port end of 4" port tubing that will be close to 6" in diameter. Even so, 12" plus 4" equals 16". That leaves you about 1" to use to fasten your driver and port on to the tube plus support the weight of the driver. I'm just not following the math here.I built a sonotube in 16" tube. Trust me, there's not enough room to put a port there, even if I had another inch or so to play with.

 

[Chuck Bogie]

Er... What about a pair of 10" drivers, one in the top, and one in the bottom?

 

[Joey_R]

What about a pair of 10" drivers, one in the top, and one in the bottom?

I was thinking of building a bar-height cocktail table with a marble top that would sit behind my livingroom “sweetspot” for additional people.

This would necessitate no ports or drivers on the top plate.

 

[TimForman]

Ok, how about this. Reduce the volume to 122L and use a Tempest in a sealed enclosure. By the time you put legs on it you'd be close to the right height. Just don't leave glasses on it during a movie. Here's mine.

 

[SteveLindsay]

If you are thinking about downfiring the speaker you are going to have to space it a couple of inches off the ground for the bass to escape. What about mounting the port on top of the tube and build a similar "spacer" between the top baffle where the port is mounted and the bottom of the marble top? The marble top would be a loading surface for the port similar to floor being a loading surface for the speaker. Just a thought.