Formula for sealed vs. ported?

 

Silver Member
Username: Stamant

LA, FL USA

Post Number: 264
Registered: Sep-04
Isn't there a formula which will tell if a sub is designed more for a sealed or ported enclosure?
 

Gold Member
Username: Nyyfan13

Fi SSD USA

Post Number: 5492
Registered: Jul-06
"Q Parameters---------Qms, Qes, and Qts are measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (this would destroy the loudspeaker). The suspension must also act like a shock absorber. Qms is a measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs. Qes is a measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is called the 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same.
As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications. However, there are exceptions! The Eminence Kilomax 18 has a Qts of 0.56. This suggests a sealed enclosure, but in reality it works extremely well in a ported enclosure. Please consider all the parameters when selecting loudspeakers. If you are in any doubt, contact your Eminence representative for technical assistance "

stolen from here:
http://www.soundsolutionsaudio.com/forum/lofiversion/index.php/t141.html
 

Silver Member
Username: Stamant

LA, FL USA

Post Number: 265
Registered: Sep-04
thank you yanks!
 

Silver Member
Username: Stamant

LA, FL USA

Post Number: 266
Registered: Sep-04
Thanks, But isn't there a formula such as qts/fs= ported or vented?
 

Gold Member
Username: Nyyfan13

Fi SSD USA

Post Number: 5493
Registered: Jul-06
ill just keep throwing threads out there for you

heres a good one which could help you
https://www.ecoustics.com/electronics/forum/car-audio/220420.html

good ole muddy and longo
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