Need port tube dimensions for JBL PB12 subwoofer cabinet

[Dan Miller]

Someone gave me a 12" speaker from a JBL PB12 sub cabinet, then tossed out the cabinet. I figure I can match up this 250w rated driver with PE 240w plate amp. The simple down and dirty way out is for me to reproduce the JBL box. I have the outside dimensions but no real idea of the port tube numbers. Any chance someone on this forum would know the port tube inside diameter and length as used in the factory made JBL PB12 cabinet?

Thanks,

Dan Miller

[Paul W]

Just happen to have one gathering dust... The PB12 uses a 3" ID flared port 12" long, including the flares. The panels on the JBL box vibrate like it doesn't have any internal bracing so you may want to build a stiffer box with the same internal volume.

[Dan Miller]

Paul,

Thank you so much.

I will take your suggestion and use some stout internal bracing.

Dan