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Speakers VERY close to wall - Cork board useful?

Hi there,

I have a set of Klipsch RP-5's, that have a built in powered sub, and a rear facing port on the bottom of each tower. I have them in a small room (15'x13') with about 6' of separation. Considering the small room dimensions I have them pushed up against the wall because otherwise they'd be in the way. They are at least at a slight angle, but the port for the sub is still only about 4" off the wall. 

Would putting a square of cork board on the wall directly behind the port, cut out so its slightly larger than the port, make any positive difference compared to an ordinary sheetrock wall?  (The cork comes in a roll, so it is maybe 1/8" thick)

Any thoughts, additional suggestions on other common house-hold materials/geometry of cut/ etc, or comments would be appreciated! (other than "move the speakers away from wall" bc unfortunately that's not an option in this room)

:)
thanks!!!
hockey4496
sbank's avatar
sbank
3,379 posts
 
Clever move, Willy. Sort of a "transmission line band aid". Cheers,
Spencer
hockey4496 OP
104 posts
 
Clever idea, I am give that a try. Thanks!
audiokinesis
2,743 posts
 

Willy Wonka’s cowl increased the effective port length and lowered the tuning frequency, which is the direction you want to go to compensate for the increased boundary reinforcement from placement near the wall.  I incorporate variable port tuning into most of my designs to deal with similar situations. 

It is also possible to lower the tuning frequency by decreasing the port’s cross-sectional area throughout its length, perhaps by inserting a smaller-diameter tube into the port. The smaller-diameter tube would be wrapped with tape as needed to get a good friction fit.

hockey4496 OP
104 posts
 
Williewonka - 
did you just slide the vent you bought into the speaker port? Or did you attach it in a particular way (modify speaker port, wrap tape to get correct diameter, etc.) I have some curved pvc tubing in the garage that may be about the right size that's could try without having to spend anymore $$ if it will work the same

thanks!
williewonka
3,075 posts
 
Hockey4496 - The cowl vent consists of two parts...
1. a plastic mount that is attached to the speaker with screws
- the opening just happened to be very close to the size of my port
2. the chromed cover which is than attached to part #1 via a latch mechanism and a single screw (If I recall correctly)

You could try the PVC pipe, lots of speakers use some kind of "plastic" for their ports.

Oooooh - I just had a vision of a speaker with dual chromed pipes on each side - just like a MAC truck - LOL

Seriously - I went with the cowl because it is metal and a much more solid solution - and I’m a big fan of solid :-)

It’s also looks very neat and tidy, hardly visible, even from the side and a little less "DIY" looking

Audiokinesis - thanks for the enlightenment - I had no idea why it worked - it just did.

QUESTION: Does the direction of the port have any effect or is it simply changing the length or diameter that causes the improvements ?

My reasoning for taking this particular approach ...
- I have observed that speakers that have rear firing ports are prone to placement issues
- whereas speakers with downward or front firing ports are better suited to closer placement to the wall behind them
- so firing the port downwards seemed like a logical choice

Cheers



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