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.
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
SIDE WALL ABSORBER
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
kept the box to a straight 8" box but you may vary width
at the left end and follow the slat shape if preferred.
REAR WALL ABSORBER
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
FINISHED ROOM WITH ABSORBERS
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.