Two subs to an enclosure, how to calculate adequate slotted port size?

[BillyJ]

Hey guys, need some confirmation/clarity on what I am getting in the form of design measurements from various online calculators. I will offer an example that closely simulates my current design restraints.

If I have two Skar SDR 8"s that require .75-1.0 cubic feet for a ported enclosure with 10.5 square inches of port area for 39 HZ... What should my measurements look like if both subs were to occupy one enclosure air space...? Do I still need .75 cubic feet per sub for a total of 1.5 cubic feet...? Will the calculations for the port of one speaker satisfy the need for both or are those figures combined as well?

Its been a minute since I built my last enclosure and I have always been under the belief when restricted on air space to award each sub individually then you can run them mono in one shared air space enclosure, etc. I will admit that might not be a correct assumption which is largely my reasoning in presenting the question to the community. Thanks in advance...

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[Jeffdachef 5,000+ posts]

Hey guys, need some confirmation/clarity on what I am getting in the form of design measurements from various online calculators. I will offer an example that closely simulates my current design restraints.

If I have two Skar SDR 8"s that require .75-1.0 cubic feet for a ported enclosure with 10.5 square inches of port area for 39 HZ... What should my measurements look like if both subs were to occupy one enclosure air space...? Do I still need .75 cubic feet per sub for a total of 1.5 cubic feet...? Will the calculations for the port of one speaker satisfy the need for both or are those figures combined as well?

Its been a minute since I built my last enclosure and I have always been under the belief when restricted on air space to award each sub individually then you can run them mono in one shared air space enclosure, etc. I will admit that might not be a correct assumption which is largely my reasoning in presenting the question to the community. Thanks in advance...

xplicit audio ultimate car audio app on your phone or torres box calculator. All online ones are pretty bad since they do take into account port displacement, bracing, 2nd baffle, and sub displacement into the design at all. So the enclosures are extremely inaccurate. You need NET airspace plus with skar i'd go closer to 1 cube per sub, not .75. You need enough port area for two speakers, you cant use the port area of one speaker for two, it has to double.

Just leave it on common chamber, no reason to do separate chambers.