Academic porting question

[tdvt]

After revisiting the fEarful thread(s), one of GB's post mentioned that the 3015LF perform better with a port area of the larger-than-average size.

That information, along with the general down-sizing of cabinets, got me wondering whether multiple ports are ever installed or are even functionally able to be on more than one face of a cabinet?

 

[fdeck]

After revisiting the fEarful thread(s), one of GB's post mentioned that the 3015LF perform better with a port area of the larger-than-average size.

That information, along with the general down-sizing of cabinets, got me wondering whether multiple ports are ever installed or are even functionally able to be on more than one face of a cabinet?

Yes and yes. Assuming all of the ports are the same length, all that matters is their total frontal area, no matter how that area is divided up among multiple ports.

There is a point to having a larger port, to reduce audible effects of the air inside the port moving at a substantial fraction of the speed of sound. The capability of the 3015LF to move more air than earlier 15's would suggest the need for a bigger port.

Given that bigger ports also have to be deeper for the same tuning frequency, it gets to be a practical matter in smaller boxes to find which face of the cab allows the port to be as long as possible inside. My next cab might very well be top or side ported.

 

[fdeck]

I should note from a design standpoint that if there are multiple ports of different sizes, they all have different "end effect," and things get a bit complicated. Also, there's a point of diminishing returns with small boxes where the port volume and complexity begin to dominate the design.

 

[tdvt]

Thanks,

On one hand it seemed logical that you could port different faces, especially with matching size ports. But then I couldn't think of any I'd ever seen & started wondering about any interaction or phase-type issues.

There is getting to be so little space to fit everything on one side of a cab I wondered why I hadn't seen one built that way.

 

[fdeck]

Probably a marketing thing. There's already a great deal of hand-wringing over front- versus rear-porting. A side ported box would have to be explained.