one or two ports on Hsu STF-3?

[lmm]

I posted over in Hsu-land, but I thought I would ask here as well. If you have a STF-3, does it have one port or two?

[curtis]

It has two ports.

[lmm]

How old is your STF-3? Am I missing something?

[curtis]

I don't have a STF-3...I have a VTF-3, but I have seen a STF-3 a couple of times.

Did you order that from Hsu or Ascend?

That looks like a 4" port as opposed to a 3" port. I would email Ascend.....or Hsu if you ordered it from them.

In any case, I would bet you got something new and improved.

[curtis]

If that is a 4" port, I believe it yields more porting area than dual 3" ports. Math guys please help me hear.

If it is a single 3" port, it means that the STF-3 is now tuned lower....probably 20hz.

If my math is wrong for the first scenario, and it is a 4" port, then I would guess it is tuned between 20 and 25hz.

[lmm]

I ordered from Ascend. The date on the sticker says 3/11/2005.

I haven't figured out what it means for a subwoofer to be "tuned". Using DVE frequency sweeps, I can start hearing the sub at around 15hz. The sweeps are too fast to measure well with my Radio Shack SPL.

I don't have any complaint with the sound -- to my ears. It's just curious that the design would change. Now at least I know what they're talking about when they say to "plug one port".

My tape measure says the single port is 4" diameter.

The area of a circle is 2*pi*r^2 or pi*d^2 / 2.

The area of a 4" port is 8*pi; the area of two 3" ports, combined, is 9*pi.

[curtis]

great.....now I wonder if the tube is longer than the older 3" tubes.

Nonetheless......it is an updated STF-3. Hopefully Hsu or Ascend will have more info.

Can you measure the dimensions of the sub?

[BradJudy]

Actually, the area of a circle is just pi*r^2. The area of a 4" port is 4*pi=12.56 sq in and the area of two 3" ports is 2*2.25*pi=14.13 sq in.

[curtis]

probably also have to consider the diameter of the flare. I thought I read somewhere that the 4" port with flare has the same flow as a dual 3" ports with flares.

[curtis]

looks like you got some of the same info over at the Hsu Forum.