# Ported Risers Q?



## RapalloAV (Aug 5, 2009)

After 10 years we have finally ported my risers as they were never filled with anything during construction, back then I didnt know they should have. They have anoyed me for years as "ever so often" I would feel the risers resonate on certain frequencies. This isnt the tactile sound I do get, it feels more like a drum under my feet from time to time. The original floor is chip board sitting on thin layer of foam then the conctete pad below. The chip board isnt attached to any walls it just floats on the foam. The risers we built sit on the chipboard floor which allow three rows of four seats. The whole entire risers and steps to the sides are all interconnected inside so none of the areas are closed boxes.

Yesterday we cut back areas of carpet and using a large 152mm hole saw created four large ports 300x152mm (4" x 12"). In the back row there are two ports through the chipboard flooring (see diag) The front riser there are two ports 300 x 152mm drilled through the risers front. It was then pretty easy with our arms and long sticks to ram in soft fluffy insulation into the entire area even through to the side steps. The whole inside area of the risers is now full from the lower floor to the seating floor area. We folded back the carpet to cover the holes which I believe is ok to do as the sound passes through the carpet.

There are 4 x 18" ported subs up front under the stage. My queston is should I add another two ports to the centre row or are the four ports large enough for the risers?

I have tested the sound after doing a new EQ and the improvement is vast, but I dont know if I should add anymore or not?


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## BP1Fanatic (Mar 28, 2011)

Did you model the enclosures in WINISD or HR to see port velocity?


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## RapalloAV (Aug 5, 2009)

BP1Fanatic said:


> Did you model the enclosures in WINISD or HR to see port velocity?


I dont even know what that means...
However we did do the middle row yesterday four ports on th risers and four ports below on the floor.
All the experts on the "other" forum told me to add the extra ports to the middle row as in the question I posted here.
The bass is now remarkable the best its ever been in 11 years since I build the room. Its really tight and the so called resonance I had in the floor is completely gone.
However I have lost some tactile but the bass is so much cleaner, punchy than ever before, worth the trade is slightly less tactile.


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## fokakis1 (Feb 29, 2012)

So basically you turned your gongs into bass traps. Fantastic! That would have bothered me as well.


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## RapalloAV (Aug 5, 2009)

fokakis1 said:


> So basically you turned your gongs into bass traps. Fantastic! That would have bothered me as well.


Yes thats what I was aiming at and the results in the room is beautiful now, Ive never been so happy! Finally CLEAN BASS!


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