Port velocity is a design trade-off
Air speed rises when a small vent must carry high volume velocity. More port area usually lowers speed, but the same tuning then needs a longer duct that can be difficult to fit and may move its pipe resonance into a troublesome range. Multiple ports share the flow while also multiplying area and construction demands.
Why 17 m/s is not a universal limit
A comparison line is useful for noticing change, not declaring audible success. Flare shape, inlet and outlet termination, wall proximity, bends, surface finish, compression, programme material, and listening distance all influence whether turbulence becomes objectionable.
Power and filtering matter
The calculator runs the actual 00 Simulator vented model from 10 to 500 Hz. Input power and the optional high-pass filter change the complete sweep. A port can look comfortable while the driver exceeds Xmax, so excursion warnings remain visible alongside the air-speed result.
What to try next
If velocity is uncomfortable, compare a larger or additional port, less power, a protective high-pass, a different tuning or volume, or a passive radiator. Each moves a constraint rather than making it disappear.
Continue with the Simulator guide, enclosure reference, T/S parameters, and model limitations.