Front or Rear Ports

[s_c_leach]

I am currently building some small mini-monitor speakers using a 4.5" Vifa driver, my question is where to put the port?

What is the difference in putting the bass reflex port at the front or at the back?
What are advantages of putting the port at the front? or the rear?

Does it really matter? as I assume that the bass radiating from the port is pretty omni-directional

Your advice please, thanks in advance

 

[andy19191]

If you want to put them on a bookshelf a rear port will be a problem.

 

[Cheap Shot]

This depends on where you plan on placing said speakers. If
you plan on putting near wall you would want it front-mounted
rear facing help fill out the lower bass but if you have a sub no
need right. But another reason would be because front baffle is
too crammed so by facing it rear it gives more room for your front baffle. hope this helps!

 

[s_c_leach]

Thanks all for you replies so quickly

I assume that I will have a tauter bass from the front firing, the rear firing will get a bass boost from the rear reflection (up to +3dB) but less focused

Correct?

 

[Ron E]

Thanks all for you replies so quickly

I assume that I will have a tauter bass from the front firing, the rear firing will get a bass boost from the rear reflection (up to +3dB) but less focused

Correct?

No. The bass sound you get will not depend on where you place the port. Augmentation from boundaries is not that sensitive that teh difference in path length of a foot or so between a front and rear fired port will make any difference at all.

The only real difference is that spurious noises from a port will be diffused from a rear mounted port and therefore less audible - using that argument, your sound will likely be purer with rear mounting....

 

[ElectroPower]

After hearing some loudspeakers, is very subjective, each one with its quality but some that frighten me are the M.A. Studio 20SE... where are the port?

With rear port, maybe you'll have some problems with ressonance...

 

[s_c_leach]

Due to lack of space the speaker will probably be placed about 30 cm from the rear wall.
The reason why I ask is that I already have a small pair of JBL mini monitors with a rear firing port. They are placed in the corner giving a some bass lift, they sound dull and life less when placed away from the the rear boundary, but then bass from a small speaker....

Sounds like I need a experiment. What I will do is make a pair with from firing port and also make another pair rear firing - I have enough of everything to make 2 pairs - see which I like the best..

 

[tktran]

IMHO the sole advantage of a front facing port is so you can place your speakers RIGHT UP against a wall.

If you have even only 10cm (4") to spare from the rear panel to the wall, use a rear firing port.

RonE has hit the nail on the head with this one...

You can build two pairs of enclosures but it's a lot of work...

 

[s_c_leach]

OK, thanks all for your good advice, sounds like a rear port is the answer.

I can also have a larger port on the rear so should reduce port velocity and thus reduce port noise.

Thanks

tktran - I have 4 woofers and 4 tweeters so will build 4 enclosures anyway...

 

[lufbramatt]

or you could put the port on the top- frees up space on the baffle, reduced effect of midrange leakage as its firing 90 degrees upwards rather than straight at you, and most speakers are taller than they are deep so it means you can use a bigger diameter port that would otherwise be too long to fit in the box.