Ported box

[TomasJ]

Hello there. Is it necessary to use a pipe/tube in ported speaker box? Or is it ok to do just hole with no bass reflex pipe applied?

Thanks!

 

[audiomixer]

you can do either, but the size / length of the reflex tunnel needs to be adjusted. that's what sets the resonance frequency together with the effective volume of your enclosure.
I've done speakers with ports being part of the wood work and others with tubes, the later being easier to adjust. you should not trust the calculators blindly, as the volume is sometimes difficult to calculate.

as a special 'gift' from the physics department - the smaller the enclosure, the longer the required reflex port for a given frequency. going to a smaller diameter helps a bit, but gives you other issues.

cheers,

Michael

 

[TomasJ]

Hey Mike! You know everything! Thanks. By the way that's about different speakers as we discussed in the other topic. In this case I am working on already build speakers just changing their cabinet. Check this picture:

http://www.spechato.cz/data/records/5f8/5f8f6254dcd818cdfc883499d0ab624a/604x453_cropc_wat1.jpg

These are the only holes in them (nothing on the back side). One hole is a basic 1,75 cm2 triangle. So 3,5 cm2 for both. The depth is no more then 2 or 3 cm for each hole. So if I do a 3.5 cm2 hole in a new wooden cabinet from 1cm ply-wood do I need to make it deeper by using some pipe/tube? Or it's not so recognisable difference in this small dimensions?

Thanks!