Front port vs Rear port

The alternative to ported (front or rear) is acoustic suspension. "Sealed" is not necessarily true acoustic suspension, indeed these days it is hard to find a woofer with specs optimized for AS. If you plug the port you do not have AS.

"The position too near the wall, so to speak, usually manifests itself in nearfield reflections, a larger problem imho than port constriction." - Lrsky

Well said - I agree 100%.

Regarding port location, note that if the speakers are designed for placement near room boundaries, the location of the port relative to those boundaries has already been taken into account. Audio Note, for instance, designs their rear-ported speakers for corner placement. Best to examine the specifics of a given speaker design rather than make decisions based on "rules of thumb" that have notable exceptions.

Even if a rear-ported speaker wasn't designed for placement near the room boundaries, in many cases it's possible to lower the tuning frequency by lengthening the port and/or reducing its cross-sectional area. This causes the speaker's inherent bass output to start rolling off higher up but not as steeply, so that it synergizes better with the additional room gain. This can of course also be done with a front port also, but it's more likely to be visually unacceptable.

One acoustic argument in favor of a rear port is that in most cases, with a bit of toe-in, your two bass sources (woofer & port) are now a different distance from room boundaries in all three dimensions. Thus their outputs will interact with the room modes a bit differently, in some cases smoothing the in-room bass significantly as compared with an equivalent front-ported speaker.

Finally, nearly all ports have a resonance in the midrange region (imagine talking through a cardboard tube), so all else being equal we'd like that unwanted midrange energy to start out facing away from us and to travel as long as path as possible before reaching the ears.

Duke
dealer/manufacturer

There's an excellent book written on ports and the noise they can create. Check out Portnoy's Complaint by Checkov.

"Finally, nearly all ports have a resonance in the midrange region (imagine talking through a cardboard tube), so all else being equal we'd like that unwanted midrange energy to start out facing away from us and to travel as long as path as possible before reaching the ears" -Audiokinesis

Bingo ... !!!

Is that 2nd or 3rd harmonic Duke?

Such a phenom is also present with large paper cone woofers playing into the midband region, such a speaker is very much favored in Horn systems, along with a front firing port system. This is very much what panel owners notice and label as "sounding boxy" when listening to monopole box speakers.

A rear firing port is best not used in a size restricted room and if listening nearfield then a front firing port system is superior. Ultimately if you have the space a rear firing port IMO is superior to the front firing for sonics..

Regards,

Weseixas, I believe that the fundamental resonance of an open-on-both-ends tube will occur at the frequency where the tube's length is equal to one-half wavelenth. For a port 6" long, that would be about 1.1 kHz.

In my opinion a nearfield or small-room setup would be where well thought-out rear porting is most likely to be superior to front porting, for reasons mentioned in my earlier post.

Duke