Rear vs. Front Port

[squidbait]

What are the advantages/disadvantages of rear vs. front porting?

[SY]

Rear port advantage: internal box noise, midrange resonances, and chuffing are less audible. Disadvantage: you can't put the speaker near a rear wall.

There's a lot of nonsense out there about how rear ports screw up phase. It's... nonsense.

[Vikash]

Just to add another practical point that Napylady makes here.

[squidbait]

Sy,

What is Chuffing?

If I want to put it up against the wall, front port is the way to go then?

[SY]

"Chuffing" is the puffy noise that the port makes when it's driven a bit too hard. A fluid mechanics guy would talk about Reynolds numbers, but I think of it like choo-choo trains.

If I want to put it up against the wall, front port is the way to go then?

Yes, absolutely.

[squidbait]

Thanks!

[hunter audio]

there is this little thing that needs consideration ,

the woofer cone when moving in its enclosure is loaded by the air mass it is displacing

this air load should be as equal as possible on the top half of the cone , as on the bottom half of the cone

in effect each half of the cone should load equal air-masses

internal chambers help in achieving this effectively ,

a pressure drop from a port on one side (side in referance to the woofer) is reduced

while using a back port there are various important issues

critical phase shifts , effect on impedance and linearity of the drive unit

this should be addressed keeping the above in mind

suranjan

transducer design engineer

[sreten]

I really don't like misinformation.

A rear port obviously cannot be placed against a wall but very
small variations of spacing near the wall will affect tuning, this
is assuming the speaker is designed for near wall placement.
If the speaker is designed for NWP the tuning aspect is beneficial.

Other than that it doesn't matter, rear placement is better as
it reduces any midrange resonance problems with the port.

sreten.

[kelticwizard]

When we say "against the wall" about how many inches are we talking about?

Would it be fair to say that there is no difference if the rear port is six inches from the wall? How about a foot? If your speaker is twelve inches deep, wouldn't a front firing port on a speaker against the wall be equivalent to a rear firing port on a speaker a foot from the wall?

I'm not denying the rear port-wall interaction, I am just wondering at which point it makes little difference.

[SY]

If your speaker is twelve inches deep, wouldn't a front firing port on a speaker against the wall be equivalent to a rear firing port on a speaker a foot from the wall?

How far is far enough is an interesting question- and I'll bet it turns out to be proportional to the port diameter. The two situations you propose here are different in that the port is firing into free air when front mounted, but into a cavity small compared to wavelength when rear mounted. It may indeed be an insignificant difference, and now you've got me hacked off that I don't have a ported speaker in the house to do some tests with.