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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: John Barclay on April 01, 2018, 10:35:48 pm

Title: ported subs proper coupling
Post by: John Barclay on April 01, 2018, 10:35:48 pm
xxx....sub box with driver lower front, ports upper front  Identical box stacked on top.  Ports together with driver top and bottom of stack OR ports on top and bottom of stack Thx  :)
Title: Re: ported subs proper coupling
Post by: Tim McCulloch on April 01, 2018, 10:49:33 pm
xxx....sub box with driver lower front, ports upper front  Identical box stacked on top.  Ports together with driver top and bottom of stack OR ports on top and bottom of stack Thx  :)

It probably doesn't matter.  How far apart are the ports in the latter scenario?

Sources within 1/4 wavelength will combine, and the bottom octave is what comes out of the port.  At 60Hz that's roughly 4.5 feet...
Title: Re: ported subs proper coupling
Post by: Ivan Beaver on April 02, 2018, 07:30:14 am
xxx....sub box with driver lower front, ports upper front  Identical box stacked on top.  Ports together with driver top and bottom of stack OR ports on top and bottom of stack Thx  :)
It depends on how high the cabinets are run, the tuning freq of the ports, the size of the cabinet etc.

It may or may or may not matter-based on the answers.

But to be safe, I would put the ports on the outsides, drivers together.

This way the drivers have a better chance of coupling at the higher freq, and since the ports are tuned at the lower freq, the wavelengths are longer, so they can be further apart and still couple.

It is all about wavelength size and spacing.