Piort distance from wall?

[Deang]

I bring this up every couple of months when I think about it.

Does anyone know the optimum distance from the wall with rear ported speakers? I know it relates to port size, but I can't remember the dag gone formula.

RF-7 has two 4" ports.

[Invidiosulus]

I think port distance depends on it's age.

I'm kind of a scotch man myself.

Peace, Josh

[lynnm]

Dean

There is no absolutely correct answer to your question. The proper wall to port distance depends on too many variables. However.....

You want to distance the rear of a rear ported speaker 18" or more from the wall behind it. From that point onward it becomes a matter of trial and error. My rear ported KLF30's for example are 2 1/2 feet from the rear wall and sound lovely. Others have reported excellent results while having their speakers,( RF7's and KLF 30's) ,much closer to the rear wall.

(As an aside it appears that both the 7's and the 30's are more critically impacted by their placement with respect to the side walls than by their placement with respect to the rear wall ).

[Dflip]

I don't have rear ports on the Cornwalls, but here is my suggestion based on moving the Cornwalls many times to adjust for new equipment, etc in the system.

Try 18" or so from the back wall and about 2' from the side wall. Then start moving 2" at a time either away or towards the wall. When the sound no longer improves (soundstage vs. bass kick) then it is time to try the other direction. At this point start with 1/2" increments, until you get it right for you.

The further away from the wall the better the soundstage and a reduced bass response. It is an art of compromise. Try to go as far away from the walls as possible while still giving yourself a good bass kick.

Good luck and let your ears be the judge.

[Deang]

Yeah, I know the rules, but man, it sure is a drag moving 100 pound speakers a half inch at a time. I was REALLY hoping someone would say something like, "One and a half times the total area of the ports".

Maybe I'll just move my chair a half inch at a time.

[marksdad]

the klipsch site recommends twice the size of the port, minimum, and i have the corns, and i originally went with user posts, held em about 18 inches in both directions toed in slightly, and yuk!!! it all depends on user ear, room acoustics. after 2 months of listening i moved the corns right next to the wall keeping them toed in and the sound stage became much larger and more defined, so it is best to experiment, let your ears be your guide

[Deang]

If you don't mind -- where did you find that information on the site?

Thanks.

[dbflash]

Dean,

Check out:

http://www.cardas.com

When you get into the site go to insights. George Cardas gives a formula.

I haven't tried it yet, but it might help. All the post's about rear ported speakers on this BB always say start 18" and move out or in.

Danny

[Deang]

yah, me knows.

I was only concerned about impeding the functioning of the port. So, it is 1.5. So now, do I have to factor in both ports (RF-7 has two 4" ports in the rear)?

Thanks!

[jnorv]

If you are really interested in this, read up on the end correction for Helmholtz resonators.

Jim N

[Deang]

Have them now 13" from the wall, 21" from the side walls, with acoustic foam mounted to the wall, next to each speaker, extending about 3 feet out -- to handle the first side wall reflection. It seems like the whole wall is acting as a baffle -- and sound is everywhere. Speakers are now 8 feet apart, center of horn to center of horn (as opposed the 6.5 they were). Center image is still stable. Highs have smoothed out, and the bass seems more even.

Interesting.