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[Tim Hite]

Hey guys, I sanded and painted the used Cabinet I got and only when I had removed the grill that I noticed the left Port's tubing was missing. I contacted EAW Parts who said they don't have that part anymore but I can use PVC or hard cardboard tubing so I am looking around for a piece of tubing with that 3-1/2" outside diameter which they had stated.

My question is, how important is that port's tubing and what's it's main purpose please? Thx.

https://www.youtube.com/watch?v=KSvknLzv2QU

You will probably want a 3" ID cardboard mailing tube that is readily available. You'll need to trim it to 11" long. ULINE has them by the case.

If you have any other questions about the design I'd direct them to http://forsythe-audio.com rather than EAW.

[Chris Grimshaw]

The biggest consideration here is having a duct with the same internal volume as the original. If you end up using a tube with a larger or smaller diameter than the original simply cut it longer or shorter as needed to keep the volume the same.

I'm afraid this isn't true.
A short wide port will have a very different tuning frequency to a narrow long one.

In order to maintain the tuning frequency, a wider port must also be longer.

Chris

[Mike Henderson]

A cardboard tube may be a better choice.  Unline sells a 3 1/4" id. expandable mailing tube.  The larger outer sleeve would be 3.43" id. Close, so not much adjustment of the length needed and should be easy to seal in place.  The is a paper company called Yazoo Mills which will custom make cardboard tubes as well.  They will do single pieces.  There are lots of plastics companies that offer plastic tubing in 3.5" id. but they are stupid expensive for single pieces.

Thanks. First I think I should wait until later this week when we should be removing the woofers to wire them with the 12guage wire, then we can take a tape and measure the port hole to know for sure what will be needed, will get back to you guys here on that.

[Riley Casey]

Yup, totally wrong. I needed to pull down my old Weems book and refresh. 

I'm afraid this isn't true.
A short wide port will have a very different tuning frequency to a narrow long one.

In order to maintain the tuning frequency, a wider port must also be longer.

Chris

[Lee Douglas]

First I think I should wait until later this week when we should be removing the woofers to wire them with the 12guage wire...

If you haven't removed the woofers yet, I would think that there's a very good chance that your port tubes are rolling around inside the enclosure.

[Tim McCulloch]

Thanks. First I think I should wait until later this week when we should be removing the woofers to wire them with the 12guage wire, then we can take a tape and measure the port hole to know for sure what will be needed, will get back to you guys here on that.

The difference between #14 and #12 wire, over the short length from connector to loudspeakers, is absolutely inconsequential.  The port duct, on the other hand, is a major deal.

[Mike Henderson]

If you haven't removed the woofers yet, I would think that there's a very good chance that your port tubes are rolling around inside the enclosure.

That's exactly what my bud who has 8 of these subs had told me. Why I thought it wasn't loose in the cab was because when I was sanding and painting the cab I did not hear anything at all move inside the cab but maybe it's caught in the damping material inside, will know in a few days for sure.

[John Roberts {JR}]

The port duct is tuned (length and diameter). Google a Helmholtz resonator for scientific explanation of resonances, but ported cabinet tuning is more complex. 

Try to use same diameter and same length tubing if possible. The material the tube is made of doesn't matter much as long as the wall thickness doesn't alter volume.

JR

PS; I am not the speaker guy here, but I know a little about it...

[Scott Holtzman]

Thanks. First I think I should wait until later this week when we should be removing the woofers to wire them with the 12guage wire, then we can take a tape and measure the port hole to know for sure what will be needed, will get back to you guys here on that.

Why are you rewiring to 12 gauge?  The wire is so short in the cabinet it doesn't make any difference. 

[Tim Hite]

Thanks. First I think I should wait until later this week when we should be removing the woofers to wire them with the 12guage wire, then we can take a tape and measure the port hole to know for sure what will be needed, will get back to you guys here on that.

Did you miss the video I posted that has the cabinet internal dimensions?

[ProSoundWeb Community]