2 Tube Vents to make equivalent from one

[krafty]

Hi.

In a enclosure with 4.1 Liters having a 17cm long x. 40mm diameter tube vent required... what length should I use if I need to switch the project to 2 tubes, one being 50mm and other 40mm diameter. (Just made a mistake with the enclosure and don't want to throw it away, these two holes).

 

[PeteMcK]

The Subwoofer DIY Page - Port Calculations

 

[phase_accurate]

I would use only the 40 mm port and cover the other hole with something that looks nice (design yourself as label).
Simple as that.
If you were to use both ports they would get quite long and use up too much of your internal volume.

Regards

Charles