more speaker questions... ports?

[solderjunkie]

Rear-ported vs front-ported?

 

Does the location of the port change the FoH sound?

 

I was reading about port design and tuning, but port location seemed to elude me.

[BoundandBlocked]

http://www.greensquare.net/acme/tech3.asp?x=3&y=3

[solderjunkie]

 

http://www.greensquare.net/acme/tech3.asp?x=3&y=3

 

 

Good link, and it explained things in a way that a non-audio-engineer-guy like me can understand.

 

Any more places with formulas and such?

[dDigitalPimp]

http://www.greensquare.net/acme/tech3.asp?x=3&y=3

 

wow i figured their stuff was expensive but never really looked before.

[boseengineer]

Port placement is not very critical, but there are certainly differences.

 

Front Port:

 

 

So overall there isn't a clear winner and the best choice depends on somewhat on cabinet size and tuning frequencies.

[solderjunkie]

 

However, too close to a wall is bad, since the wall restricts air flow and "chokes" the port at high levels.

 

 

I feel this had a negative effect on my cab.... it was only an inch or two from the wall when the drivers split.

[boseengineer]

 

I feel this had a negative effect on my cab.... it was only an inch or two from the wall when the drivers split.

 

 

That's quite possible. How far away you need to be depends on the design of the cabinet, or in particular the "particle velocity" in the port. That's how fast the air moves back and forth. If the port diameter is farily large, the air moves slower and you can get closer to the wall. A smaller port will cause more problems.

[solderjunkie]

 

That's quite possible. How far away you need to be depends on the design of the cabinet, or in particular the "particle velocity" in the port. That's how fast the air moves back and forth. If the port diameter is farily large, the air moves slower and you can get closer to the wall. A smaller port will cause more problems.

 

 

 

4" diameter round port, 3.5" long.