Re: No compromises front loaded double 18” cab
Large displacement drivers need a large "slug" (or slugs) of air, or the port(s) will be "blown out" at high excursion, "port compression".
Four corner triangle ports will brace the cabinet well, and are a near optimal use of the cabinet frontal area. They also provide symmetrical cone loading, which reduces cone rocking motion. Rocking can cause distortion, and even voice coil rubbing and destruction.
Four round ports require less frontal space than one port of the same volume, and are easy to figure with most calculators, as corner ports tune a bit lower than the volume would suggest.
