I think this question is likely much simpler than most others relating to ports...
I'm building a pair of CSS Criton 2TD-X Towers from scratch. The design includes two 2-inch diameter, 7-1/2" long tubular ports located side-by-side in the back panel of each speaker, with the bottom edge of the ports just about an inch from the bottom. They're below the binding post cup (which I won't be using as I'm going with GR Research tube connectors).
The towers are only 8.5" wide (7" inside), and I'd like to stack the two ports vertically instead of placing them side-by-side; I'd also replace the stock straight tubes with the flared 2" Precision Port units. I'd keep the port length the same, seeing no reason to change it.
Anyone see any problem with this?
Thanks!
I'm building a pair of CSS Criton 2TD-X Towers from scratch. The design includes two 2-inch diameter, 7-1/2" long tubular ports located side-by-side in the back panel of each speaker, with the bottom edge of the ports just about an inch from the bottom. They're below the binding post cup (which I won't be using as I'm going with GR Research tube connectors).
The towers are only 8.5" wide (7" inside), and I'd like to stack the two ports vertically instead of placing them side-by-side; I'd also replace the stock straight tubes with the flared 2" Precision Port units. I'd keep the port length the same, seeing no reason to change it.
Anyone see any problem with this?
Thanks!
As usual, it's a little more complicated than it may seem.
The calculation involves some parameter changes as air is treated as a fluid ( as it is! ) so talking about 'viscosity' might not seem strange.
Aerodinamically the flares determines a gradual change of impedance ( of the air mass) than an abrupt cut
I d0n't remember if the ports should be shorter or longer than the ones with flat exits. Probably shorter...
The calculation involves some parameter changes as air is treated as a fluid ( as it is! ) so talking about 'viscosity' might not seem strange.
Aerodinamically the flares determines a gradual change of impedance ( of the air mass) than an abrupt cut
Did you roundover the end attached to the box, as lot of pics by builders show? You could just make similar flares from wood and glue them to the internal end.
If you do go with a Precision Port, consider stepping up to a single 3".
Whatever size you go with for the Precision Port, remember that only half of each flared is counted as port length. For a 2" PP, I think the flared end adds about 1" on each end. So half of each end = 0.5", times the two flared ends = 1". In your case, subtract the 1" from 7.5" = 6.5" for the straight center section.
If you do go with a Precision Port, consider stepping up to a single 3".
Whatever size you go with for the Precision Port, remember that only half of each flared is counted as port length. For a 2" PP, I think the flared end adds about 1" on each end. So half of each end = 0.5", times the two flared ends = 1". In your case, subtract the 1" from 7.5" = 6.5" for the straight center section.
Thanks to both of you. I did a bit more research and subwoofer-builder.com states "The generally accepted adjustment is to subtract half the flare radius from the physical length to obtain the effective length." Also, I found a port length calculator that accommodates flared ports on the Precision Sound Products website.
