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What are the factors that go into determining whether a ported speaker has a front or rear port?It would seem easier to put it on the back as there's more real estate but that would increase boundary effects (perhaps desired, no?
The reason for asking is that I noticed GR Research has a speaker that's normally ported out the back but they port it out the front for a center channel. Is it correct to assume that the front ported speaker sounds different, perhaps not as good, as the rear ported one?
Follow Ups:
I recommend the port to be in the rear.The only reason the front ported enclosure was designed was for cases in which the center channel speakers was placed in an entertainment center where it would not have adequate air space behind it for the rear port.
Danny Richie
Another factor not yet mentioned in this thread is the issue of midrange radiation out the port. Most ported systems have an open internal volume, and only a little absorbent material on the walls. This leads to internal reflections in the midrange that can enter the room through the port. With a front port these will be more audible than with a rear port which makes them diffuse and less directional. This is more of a problem with 2 way designs with their higher crossover, so the mid-woofer covers a lot more range. At higher frquencies you can also get port resonances, again more audible with a front port.On the other hand, a front port does give more freedom of placement. Such as near a wall, or in a bookshelf.
A rear port generally is a signal that the speaker is designed for placement away from the wall.
heck, I have some vintage furniture grade cabs on Queen Anne style legs that vent to the bottom, via an adjustable slot vent. works fine.
I prefer to put the port on the rear of the enclosure, as that minimizes any "chuffing" noises that may be generated. As long as the speaker is placed out from a wall, this works well. But in the case of a center channel speaker, many are placed in a wall unit or other type of enclosure which would obstruct a rear vented enclosure.
Also, check this site out. This company uses a "slot" at the rear and bass is quite extended. This type of slot is used on my Energy 22 Ref Conns with very good success.
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