port shape - circle vs. thin slot, why?

Slot loading tends to reduce port noise, which is derived from turbulence within the port. Depending on how the slots are achieved, it can also be less costly and time consuming for the manufacturer to achieve as compared to a tuned duct. The best ports have radiused inlets and outlets with "dimpled" ( like a golf ball ) surfaces inside of them. These are also the most costly ports to make and use, hence their lack of commonality on the market. Sean
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Miller and Kreisel has a new pair of active monitors with a plug you can put in the port hole (round) when using the speakers with a sub. What do you think of that idea, Sean?

Dnewhous: B&W also has a set-up like this on some of their smaller speakers. As to my thoughts on this, i think that it adds versatility to the speaker. I also think that neither tuning would be optimum as each type of bass alignment requires very specific operating conditions in order to obtain optimum results. Trying to satisfy both types of operating constraints may provide a more "universally acceptable" product, but it will be a product that isn't at or near the top of the ranks in either category. Sean
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