Mixing port sizes???

[oxsign 5,000+ posts]

I know we've talked about mixing sub sizes, but what about port sizes? Say for instance putting a 6" flared port and 2 4" flared ports?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif I've just wondered about the effect it would have?

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[IgnoreMe 5,000+ posts]

i would say none.

should act just like the other ports IMO. i mean yea they are smaller but all your really doing is adding port area so the air has less resistance coming out anyways.

just to clarify this is just a GUESS. no experience here.

 

[oxsign 5,000+ posts]

Anymore input on this???

 

[germanyt 10+ year member]

If you mean ports that are tuned to different frequencies then it will not work. If you mean simply adding up the port area and making them all the same length then maybe but there is still a chance it will not work out the way you want.

 

[jellyfish420 10+ year member]

If you mean ports that are tuned to different frequencies then it will not work. If you mean simply adding up the port area and making them all the same length then maybe but there is still a chance it will not work out the way you want.

well that doesn't even make sence...if you have 2 diff size ports, that are the same lengths...they will be tuned at diff freq.

to the op, i've been wondering the same thing myself. my next build is gonna have to be built in the trunk, and i wanted to tune it in the mid 30's, but want to be able to take off a "port cover" if you will, to reveal another port that would both add port area, and change the tuning higher. i'm sure i could do something, but i haven't sat down to figure it out yet. i'll prob, just do interchangeable port.

 

[iagrdshaka 5,000+ posts]

I know we've talked about mixing sub sizes, but what about port sizes? Say for instance putting a 6" flared port and 2 4" flared ports?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif I've just wondered about the effect it would have?

I would never do it personally.

 

[Lakota 5,000+ posts]

Change the tuning via port area.

 

[PSturmer 10+ year member]

i would never do it

 

[germanyt 10+ year member]

well that doesn't even make sence...if you have 2 diff size ports, that are the same lengths...they will be tuned at diff freq.to the op, i've been wondering the same thing myself. my next build is gonna have to be built in the trunk, and i wanted to tune it in the mid 30's, but want to be able to take off a "port cover" if you will, to reveal another port that would both add port area, and change the tuning higher. i'm sure i could do something, but i haven't sat down to figure it out yet. i'll prob, just do interchangeable port.

that is exactly what I was saying. it wouldn't work because the two ports would be tuned to different frequencies. and the freq you tune to would be inacurrate because the loss of pressure in the box due to the other port would affect tuning of the other port. I think at least. It doesn't seem to affect it in a multiple, same tuned port application but I'm sure there would be undesired effects. if you used multiple, different sized ports. Say a 6 inch and 2 4 inch ports. you may be able to add up the total area and figure length as though it was one port with the same area.

 

[Pl8er 5,000+ posts]

I wouldn't do this. By doing this and then spilling the blood of a virgin canadian, you will bring Satan back!

IT SHOULD NEVER BE ALLOWED!

 

[jmanpc 5,000+ posts]

So long as you compensate for the length to keep the correct tuning... I don't see why not...

 

[oxsign 5,000+ posts]

So long as you compensate for the length to keep the correct tuning... I don't see why not...

This is what I was figuring. If you can figure out the length of the 6" port tuned to say 34hz, and you find out the length of the 2 4" ports tuned to 34hz. Wouldn't that work? I'm just trying to understand "why" it wouldn't work.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[bigbang 10+ year member]

I know the correct way for tuning multiple ports is to divide the volume of the box (after displacements) by the number of ports, then tune each port for that smaller box volume. This if for identical ports though (Same port area).

I'm wondering if you would divide the box volume into smaller volumes proportional to the port areas of each port, then tune each accordingly, for instance the 6" port would be tuned by a larger box volume than that of each of the 4" ports. I would suppose that if all ports are tuned at the same frequency and based around different box volumes to perform thier share of the airflow, they would experience port noise at around the same volume level. This thread got me thinking, curious to see how its done...

 

[jellyfish420 10+ year member]

I know the correct way for tuning multiple ports is to divide the volume of the box (after displacements) by the number of ports, then tune each port for that smaller box volume. This if for identical ports though (Same port area).
I'm wondering if you would divide the box volume into smaller volumes proportional to the port areas of each port, then tune each accordingly, for instance the 6" port would be tuned by a larger box volume than that of each of the 4" ports. I would suppose that if all ports are tuned at the same frequency and based around different box volumes to perform thier share of the airflow, they would experience port noise at around the same volume level. This thread got me thinking, curious to see how its done...

thats kinda what i was thinking...diff ports for diff areas of the box, i might have to build a test box to see what happens //content.invisioncic.com/y282845/emoticons/up2something.gif.dd110ecf3ae4b76050d87598f2f8de7c.gif

 

[bigbang 10+ year member]

Jellyfish420

Just applying your idea to one of my old boxes, I took a 1.25cube box tuned to 35Hz, added an extra port the same exact size (Manipulated the tuning frequency to achieve this result with WinISD beta), ended up with a box tuned to 49Hz. I kind of like your idea vs having interchangable ports, block one off for SQ, open it for SPL.