SB34SWNRX sub

[mordikai]

I built a sealed box out of curiosity, 50L as suggested by winisd.

Don't really like how it sounds, I simulated a linkwitz transform curve and still doesn't sound as effortless as the ported box.

I typically prefer sealed but I've had many ported speakers that sound great.

 

[bogdan2011]

I typically prefer sealed but I've had many ported speakers that sound great.

It's actually the first time I built a ported sub, even though the driver is better suited for sealed.

First listening opinion: it seems that the ported box has better separation of the bass notes, they sound well defined. Obviously, I don't have to drive the amplifier that much since the bass is easy to hear even at low volume. The sealed box seems to sound a bit boomy and muddy.

 

[GM]

Is extending the vent outside the cab as required to get the needed port area really that big a cosmetic no-no?

GM

 

[bogdan2011]

I don't see how I could make it look nice

Is extending the vent outside the cab as required to get the needed port area really that big a cosmetic no-no?

GM

 

[bogdan2011]

It seems that WinISD doesn't simulate port velocity correctly, and I can't find the reason why.
As a rule, I've read that the port area should be 1/3 of the cone area.

I went back to my original design with a rectangular port. I'm tempted to try this one as well.

 

[bogdan2011]

I went and got a 100mm pipe and elbow and experimented with different lengths.
I settled to around 35cm of length (enough to leave about 7-8cm of space from the back wall).
Chuffing only occurs under 30Hz and at high levels, that I don't think will be achieved with music.

Also, surprisingly, increasing the length doesn't alter the response that much.

 

[USRFobiwan]

that looks pretty decent. most of the time the port has to be shorter than predicted in the sim. a flare can improve response somewhat although only minimal. Also experiment with some fillings since port lengths work in correlation with box volume. And since the tube is inside the box, you need to compensate for the box volume.

 

[mordikai]

I went and got a 100mm pipe and elbow and experimented with different lengths.
I settled to around 35cm of length (enough to leave about 7-8cm of space from the back wall).
Chuffing only occurs under 30Hz and at high levels, that I don't think will be achieved with music.

Also, surprisingly, increasing the length doesn't alter the response that much.

7-8 cm seems like plenty of space but I will often cut the port tube at an angle on the chop saw to give it more room while maintaining as much length as possible.

 

[bogdan2011]

I've noticed that the woofer runs out of excursion fairly quickly. Can it be a misalignment issue or simply the limited Xmax? It is given as 11mm one-way.

 

[chris661]

Are you running with a highpass filter to protect from VLF (very-low-frequency) signals?

Chris

 

[bogdan2011]

Are you running with a highpass filter to protect from VLF (very-low-frequency) signals?

Chris

Not yet, but I tested it with a digital high pass filter and I don't see any notable difference.

 

[bogdan2011]

I eventually built a proper active subsonic filter and I can say it makes a whole lot of a difference. I can still get it to distort since it's tuned pretty low, but by the time it does that, it's very loud anyway.