2. speakers
  3. 124515-9953

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
hockey4496 OP
104 posts
 
Thanks for the feedback guys. I'll look into gikacoustics, but in the mean time y'all don't think the cork would have any value with the current setup? 

Thankfully the sub output is adjustable via a dial on the back of the speaker. Overall the sound is great, especially with digital sources. What made me wonder about using cork though is when playing vinyl, some records sound perfect with the sub adjusted to say 25%, then on others 25% is loud/boomy and over shadows the treble/mids so I have to continually adjust both speakers up and down between different albums, and occasionally even between songs on the same record. 

Ive tried varying tracking forces on the tone arm and it doesn't have an effect on the bass issue described above so I thought maybe playing around with the surface of the wall could level out the acoutics a bit so the lows aren't so sporadically over powering
williewonka
3,075 posts
 
Hockey4496 - unfortunately cork is not the solution for this problem.

You would achieve better results from carpet or rug as suggested by Czairvey. Underlay under the carpet will also help.

An option that I have tried with great success it to redirect the direction of airflow from the port by installing a Perko Chromalex Cowl Vent over the port.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=11143&familyName=Perko+Chrom...

It worked very well in my case and made the speakers perform so much better across the entire bottom end - almost eliminating the muddiness and booming I had before..

Once installed, moving the speakers out just a couple more inches will improve things further.

Since you have carpet on the floor I would try pointing the vent downwards first.

Crazy Option ??? - maybe, but it worked

And - it's cheaper than new speakers :-)
sbank's avatar
sbank
3,378 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
2,737 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.

More to discover