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DIY Wall Units

THE CORNER ABSORBER

The following are drawings in imperial and metric for a corner slot resonator for low-mid absorption. It consists of a MDF box with varying slats on the front installed with varying gaps. The variables are the depth from the wall, the width of the slats and the width of the gaps between the slats. The box created must be completely sealed to be airtight. The only access to the outer air is via the gaps between the slats.

 

Imperial

Metric

 

Depending on the variables used this will create an absorber in the 150Hz - 500Hz range. Calculation for the slot width/slot depth etc. etc. and the frequency created can be done using this calculator at this link

 

THE SIDE WALL ABSORBER

This unit is similar to the corner unit except that it's designed to work on the side walls thus breaking up side wall reflections and standing waves created between parallel walls. Construction is similar to the corner units where the unit must be air sealed to achieve the desired effect. Because the depth from the wall isn't as great the frequencies absorbed are slightly higher. The rear of the unit is covered by plywood to create a sealed unit.

Imperial

Metric

I've kept the box to a straight 8" box but you may vary width at the left end and follow the slat shape if preferred.

 

THE REAR WALL ABSORBER

This is similar to the above but without the slats. The isulation should be a rigid fibreglass for maximum absorption at the lower frequencies. The isulation is also lifted off the wall to lower the absorption frequency. A couple of these placed across the rear wall (rear to the mix position) will stop rear reflections confusing stereo image. I've only done an imperial as the europeans and aussies can make the adjustment

 

THE FINISHED ROOM WITH ABSORBERS

As you can see from this layout we haven't used a lot of high end absorption. The corner units and the side units are both reflective or diffusive to the highs. It's only the front and rear units that actually absorb the highs and they are in balance to the other units. The result will lower the reverb time of the room evenly across the frequency range.

Hope this helps

Cheers John