Where to get long flared ports? (1 Viewer)

[Ryan Schnacke]

I'm closing in on a design for my ported DVC subwoofer and Unibox tells me that if I use a 105L box (net), 4 inch port and tune to 20Hz the port would be 19.5 inches long and the port air speed would be pretty high. If I go with a 4 inch dual-flared port it needs to be 20.5 inches long.

The Aeroports and Madisound flared ports are only 16-17" long (I think). So where can I get longer ports? Are there flares that work with PVC pipe for the center length?

I could go with a couple of 3 inch non-flared ports. That gives me about 12% more flow than a 4 inch non-flared. Might be enough. Going all the way to 6 inch diameter makes it REALLY long. Tough to fit in a box.

 

[Dustin B]

I assume you are talking about the Dayton DVC 12" driver. If so I wouldn't worry about the air flow in a 4" flared port with that driver. Several people on this forum have not had any port noise problems with a Tempest and a single 4" flared port.

As for how to get the port 19.5" long with one of those port kits, got me. Unless you can find some PVC pipe that will fit on those flared ends.

 

[Jack Gilvey]

4" PVC should fit those flares, those two makes are the only ones I'm aware of. I'd much rather go with a 4" dual-flared than two 3" non-flared ports. They may have 12% more port area, but the actual flow gain will be less due to increased internal friction, and the 4" dual-flared may end up actually having more flow capability.

There are two main issues with ports, compression and noise. The flares are very effective at reducing noise, so I believe port compression could still be a factor long before noise is apparent (although flared ports do increase output/decrease compression also), which is why I don't really consider lack of noise as the sole determinant of suitability of a given port size for a driver/alignment. I don't think you'd have an issue with either with the DVC, though, depending on the power used.

 

[Ryan Schnacke]

Dustin,

Yes this is the 12" Dayton DVC.

Jack,

I know internal friction is a factor. I was a bit hesitant to even mention dual 3" ports when the gain is so small. The only other benefit would be the ability to plug one port for deeper tuning ala HSU/SVS. But I've been so happy with my 25-31 that I can't imagine needing a sub tuned below 20Hz.

There's a few bits and pieces I want from PE anyway, so I'll get an Aeroport while I'm at it. As always you're a great help.

Ryan

 

[Brian Bunge]

Ryan,

I believe those 4" Aeroports are still on backorder. At least they were Tuesday when I placed my order. Thankfully the 12" DVC's are back in stock! My order should arrive today!

Brian

 

[Ryan Schnacke]

Thanks Brian. It may be a week or two before I can start this project anyway.