Lowering tuning freq.

[qtipextra 5,000+ posts]

Not on a port thats already 23.5" long. That would bring it to 28.5 hz. Thats good enough for me.

The only thing with doing it that way is like PowerNAudio was saying - Port noise. I dont know if taking down that much area of port will affect it or not. I guess I can do a combination of both, because I'd like it about 4^3 ft, at 28 hz. Right now, its 4.5^3 ft @ 33hz.

 

[mazdakid 5,000+ posts]

do you want to know how long it would have to be or are you going to figure it out yourself?

 

[PSturmer 10+ year member]

The box I have is actually tuned to 33hz. I would like to tune it to about 28hz. My question is, can cutting a piece of wood and adding it to the current port work? I know it will lower the tuning, but is that a good way to do it without building a new box?

you should cut a piece and add it to the outside of the box.

i made a graph to show what would happen if the port length in the inside of the box decreased or increased. since the boxes volume changes when the port length differ's it did not make a large difference. adding 4 or subtracting 4 inches off the port length would only change the tuning freq by 1hz.

but i dont see why you cant just glue a rectangle on the outside of the box to just extend the port length

 

[qtipextra 5,000+ posts]

do you want to know how long it would have to be or are you going to figure it out yourself?

No, I already have it figured. Make length a total of 30 in (from 23.5 in). From that, add 1/2 in thick mdf to the entire new length of 30". Thats 28.44hz. //content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif

That would bring box to 4.28^3 ft net, and a 28.44 hz tuning. Now I just gotta figure if I can fit the pieces into the box.

 

[iamamp3pimp 5,000+ posts]

a rebuild is in order.

but if not, then you should remove the port wall, cut a huge hole in the front of the box, add a new baffle for simplicity, and flushness, and try some like this

http://www.caraudio.com/forum/showthread.php?t=177780