[Speakerpeeper]

Hello, new member here that cannot search so forgive me if this has been talked about before. I'm interested to know what people have used to plug ports in subwoofers. I read one suggestion about using Peewee footballs for this purpose. Any other ideas? Thanks!

[Letitroll98]

The good ol standby, a pair of unused socks rolled up.  I've never liked the resulting sound so never went past the experimental stage to find something more permanent.

[planet10]

I have used a lot of things, My favourite is open cel foam. My source of foam allows for making disks that can be added to the vent to acheive just the right amount of speriodic damping.

dave

[E-Zee]

Planet10 beat me to it.  I've tried several materials as port plug and a couple inches thick of open cell foam seems to be the best.  It won't truly seal the port but it shows down the air movement significantly.  It is the best compromise, since the ported cabinet is not sized for a truly sealed design.

Elon

[Letitroll98]

Which then is the next question, what is the goal of dispensing with the original design?  As I understand it aperiodic damping is to lower qts and raising f3, but not so much as completely sealing the port would.  I've read that the only reason to do this is to compensate for motors not strong enough to control the cone, in other words a fix for flabby bass.  But the op here is asking about completely sealing the port if I read correctly.  I'm not the expert on this so please weigh in with any corrections.

In googling this I came across a writer using metal discs with holes drilled in it to create the aperiodic damping.  That got me wondering about the math.  Again asking the speaker building experts here, is there any formula for restricting air flow in speaker ports?  And shouldn't that have been done in original design?  Thanks for any input.

[nlitworld]

I have done this in the past with microfiber towel loosely stuffing but not completely filling the port. It fixed flabby boomy bass and allowed for better integration of the subwoofer. Not a perfect fix, but a much better option than a giant 50hz spike in room response.

[planet10]

Which then is the next question, what is the goal of dispensing with the original design?

There are many poorly designed reflex boxes that get better when the vent is stuffed.

dave

[tull skull]

Have you heard of the straw solution? You stuff the port with straws and I believe the length of the straw contributed to the performance. I honestly can't remember if this was eventually seen as a positive solution or not; sorry. The cost should be pretty painless so maybe worth a try?

[planet10]

Have you heard of the straw solution?

One of my first exposures to pushing things aperiodic. Sometime early ‘70s.

dave

[Peter J]

Have you heard of the straw solution? You stuff the port with straws and I believe the length of the straw contributed to the performance. I honestly can't remember if this was eventually seen as a positive solution or not; sorry. The cost should be pretty painless so maybe worth a try?

Straws in port is about promoting laminar airflow within the port. It was a big talking point some years ago but seems to have lost traction. It probably did accomplish, at least in part, what it was said to do. I suspect the question of actual sonic improvement via laminar flow through the port was just never really proven.

 I had a pair of North Creek Rhythms (Geroge Short) that used the method. The port was somewhat adjustable in length as the straws could be extended beyond the port tube itself.

Did it make a difference? Dunno, I never tried it without them in place.

[Speakerpeeper]

Lots of cool ideas to experiment with! I think I'll try the open cell foam and will report back. This is for a diy swarm sub system using three cheap subs from cl wired in series to a bridged 250 wpc amp through a MinDSP. I. haven't even broken out the testing mic yet but the port plugging will be part of that process.