Sonosub questions

[Jeff Beaird]

I have a question on port sizes using sonosub.exe.
I'm using a Tempest 15" from Adire.
At the recommended volume, 9+ft3 they recommend a 6" port at over 2 ft. and with a 4" port it is less than a foot long.
It baffles me on why a 6" port is longer than a 4" port both flared.
An 8" port is even longer..????????? What the ...?

It seems backwards to me. What am I missing?

[Jeff Beaird]

Am I unclear with my question? Or is it too stupid of one?
Hell, come on guys, I'm a big boy you won't hurt my feelin's...:confused:
I've built a lot of auto sub boxes and never messed with different size ports.

[dane_peterson]

Jeff,
If you could provide the specifics about your sub parameters, it may help one of us solve the issue.

I bet you're looking forward to those Mon 10s! :D

[Jeff Beaird]

they will be here soon..! I can't wait.
Thanks again..!

[GV#27]

At the recommended volume, 9+ft3 they recommend a 6" port at over 2 ft. and with a 4" port it is less than a foot long.
It baffles me on why a 6" port is longer than a 4" port both flared.
An 8" port is even longer..????????? What the ...?

It does seem a little counterintuitive but yes a smaller diameter port will actually be shorter than the larger dia port for the same tuning freq.Researching helmholtz resonators might give the answer as to the physics involved in how the little slug of air in the little port can tune to the same freq as the big port.

[Shicks18]

all about the air speed flowing through the port. with an enclosure that big you need either a 6" port or multiple 4" ports.

[Jeff Beaird]

It does seem a little counterintuitive but yes a smaller diameter port will actually be shorter than the larger dia port for the same tuning freq.Researching helmholtz resonators might give the answer as to the physics involved in how the little slug of air in the little port can tune to the same freq as the big port.

Now that makes sense... Thank you, thank you. I can relate my previous experiences to this now and it makes sense. Duh..!


Hey, you can't learn w/o asking some stupid questions:o

[GV#27]

all about the air speed flowing through the port. with an enclosure that big you need either a 6" port or multiple 4" ports.Your correct, air speed will be higher in the smaller diameter port but he was refering to the tuning which is not determined by air speed but by the mass of air in the port.





Hey, you can't learn w/o asking some stupid questions:oIt wasn't a stupid question in the least.

[Deadof_knight]

point blank ports work this way... the smaller the shorter simply stated its more restrictive.....

in order to acheive a given restriction the bigger you go the longer it must be ..... given there are more items too explain here this is the simple lamens terms ... if anyone else cares to chime in please .....

[Deadof_knight]

Shick it is about about air speed and it also has to do with both your speaker and the enclosure .... its not all about the enclosure..

[GV#27]

.... its not all about the enclosure..In an overall system sense ofcourse the driver will be part of the equation as the enclosure volume and port tuning must be optimized in relation to the drivers T/S parmeters to get the desired response.However the port/enclosure tuning relationship is independant of the driver.

[Deadof_knight]

Point taken ...... Im sure he is going I thought this would be simple hahahahaha






I do have to say this Im not a fan of the ported variety ..... in subs that is ..... but Ive read enough and messed up my fair share of ports or box sizes trying to get the sound I was looking even though the frequency meter said it was right !!!

[GV#27]

I do have to say this Im not a fan of the ported variety ..... in subs that is ..... I'm with ya on that one.As for sheer sound quality I have had the best results with sealed and TL's.However a big vented sono is hard to beat for HT.

[Shicks18]

Well I think its a give and take between SQL and SPL on sealed vs ported. Depending on the quality of the driver and wattage of the amp you can obtain both in either enclosure.