retuning a slot port

[wevie 10+ year member]

Greetings,

A year or so ago I build my first enclosure. I was using a Kicker CVR (yeah, I know, but I was learning) and built the box to the owners manual's specifications. I later realized that those specs: 2.25ft^3 with 3"x12.5" slot 20.5" long; come out to a tune of about 42 hz!!!

I want to retune the box and reuse it. I'd like to bring the tune down to 32-33 hz. Using the12volt calc, it looks like I could change the slot to 3"x7.5" at 20.5" long. Would a 22.5in^2 port be too small?

The only way I can see to lower the tune without reducing the area of the port is to extend it outside the box another 16".

Which route would be a better choice?

**I know this isn't an IDEAL situation, but all I am doing is PLAYING around with tuning and LEARNING what works. This isn't a permanent installation**

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[dragnix 5,000+ posts]

since you can't extend the port outside the box (?) it looks like you'll have to make the port smaller. It's not small if that is for 1 sub

 

[RAM_Designs 5,000+ posts]

3"x7.5" will work fine if you're just experimenting with tuning. If building a new box I'd do a little more port area, like 30in^2.

 

[wevie 10+ year member]

Forgive my newbness... but it's not impossible to extend the port outside the box, is it? I've seen pics of aeros outside the box, why not a slot?

But, if that port area isn't too small for a single 12, its all good for playin' around.

 

[dragnix 5,000+ posts]

because that port won't be enclosed...if it is, it won't be extending out of the box. I think that makes sense.

That port area is good enough for 1 12"

 

[RAM_Designs 5,000+ posts]

It wouldn't be hard to extend the port outside the box, but I doubt you have an extra 16" to do it...just build a rectangular tunnel the same opening as the port, and glue it to the port opening.

 

[dragnix 5,000+ posts]

It wouldn't be hard to extend the port outside the box, but I doubt you have an extra 16" to do it...just build a rectangular tunnel the same opening as the port, and glue it to the port opening.

hmm...i now see what you're talking about, I was thinking of it a different way. However, it certainly doesn't seem ideal

 

[RAM_Designs 5,000+ posts]

However, it certainly doesn't seem ideal

Definitely not...just awkward in general.

 

[wevie 10+ year member]

It wouldn't be hard to extend the port outside the box, but I doubt you have an extra 16" to do it...just build a rectangular tunnel the same opening as the port, and glue it to the port opening.

That's what I was thinking, too. I can picture it in my head, and I could see it allowing me to try different port lengths, thus different tunings. Then I could learn first hand how that affects the overal "feel" of the system.

 

[RAM_Designs 5,000+ posts]

That's what I was thinking, too. I can picture it in my head, and I could see it allowing me to try different port lengths, thus different tunings. Then I could learn first hand how that affects the overal "feel" of the system.

True, that would be easier to adjust the tunings...just do like 4" increments to change it ~2.5hz at a time.