Many
recording studios have monitors that are set on stands creating
a midfield monitoring space. The designer type studios usually have
their monitors built right into the walls, soffit loaded but many
studios are not designer built and simply have their midfield mains
sitting out in the open, on stands.
The
midfield monitor acts like most dynamic speakers. Treble expands
out generally in a forward direction from the monitor while the
bass expands out with equal power in all directions. The treble
range directivity has a cardioid pattern while the bass range pattern
is omni.
The ears of the mixing engineer are
about 4 feet off the floor and so are the monitors. Unfortunately,
most monitoring rooms have an 8 foot high ceiling. The direct wave
from the woofer of the monitor is strongly affected by the reflections
from both the ceiling and the floor. These two reflections travel
8 foot round trip paths and meet together right in front of the
speaker driver. This causes the air in front of the driver to have
a density that is not normal, but that has been preconditioned with
an 8 foot or 7 millisecond delayed version of the original signal.
A downtown designer studio will have
the mains mounted in the wall, typically "soffit loaded".
A monitor stand can be modified to play better by adding a baffle.
This supports the expanding bass wave, directing more of it towards
the engineer and allowing less to expand in the wrong direction,
away from the speaker and into the room. Baffles have to be carefully
built so they do not color the speaker they are trying to help by
reinforcing the wrong frequency range. A good baffle design should
support the bass and absorb the midrange. The stand that supports
the midfield speaker can also be modified to do more than simply
look good while holding the speaker up off the floor. It can be
converted to become part of the baffle "wall", helping
to further manage the expanding wavefront.
Here
is shown a setup of StudioTraps and TubeTraps used to configure
a free standing acoustic baffle/pedestal. This is the basic building
block for the ATTACK Wall. It compensates for and cleans up the
distortions introduced into the direct signal that are caused by
speaker that is supported midfield on a speaker stand.
A baffle board increases the efficiency
of a woofer, similar to a short horn that is used to load air onto
the diaphragm of a woofer. The expanding wavefront is also directed
more to the front than behind the speaker. There is always much
less bass in the space behind a baffle loaded woofer. More than
loading, this baffle system stops short of both the wall and the
floor, causing the bass wave front to skid around the edge of the
baffle and impact both the ceiling and floor at an angle and softly.
This venting of the bass wave just before impact reduces the strength
of the phase cancel/add effect due to the otherwise strong bounce
back effect.
The
effect of combining wavetrains (comb filter) from strong and simultaneous
floor and ceiling reflections with the direct signal at the face
of the speaker is reduced by adding vents at the edges of the baffle
board. In addition to the venting effect of the baffle, the bass
bounce at the floor can be further reduced by adding a bass range
sound trap in the reflection pressure zone of the floor bounce.
The
net effect of edge venting and bass trapping the floor bounce is
to eliminate the excess buildup of time delayed pressure signal
right near the woofer diaphragm. Especially important is that the
conversion of Kinetic to Potential Energy does not happen unless
the two wavetrains are of equal strength. By weakening one over
the other, the Kinetic Energy of the other is never converted to
Potential Energy and remains unfelt by the woofer.
Many
recording studios have monitors that are set on stands creating
a midfield monitoring space. The designer type studios usually have
their monitors built right into the walls, soffit loaded but many
studios are not designer built and simply have their midfield mains
sitting out in the open, on stands.
The
midfield monitor acts like most dynamic speakers. Treble expands
out generally in a forward direction from the monitor while the
bass expands out with equal power in all directions. The treble
range directivity has a cardioid pattern while the bass range pattern
is omni.
Here
is shown a setup of StudioTraps and TubeTraps used to configure
a free standing acoustic baffle/pedestal. This is the basic building
block for the ATTACK Wall. It compensates for and cleans up the
distortions introduced into the direct signal that are caused by
speaker that is supported midfield on a speaker stand.
The
effect of combining wavetrains (comb filter) from strong and simultaneous
floor and ceiling reflections with the direct signal at the face
of the speaker is reduced by adding vents at the edges of the baffle
board. In addition to the venting effect of the baffle, the bass
bounce at the floor can be further reduced by adding a bass range
sound trap in the reflection pressure zone of the floor bounce.
The
net effect of edge venting and bass trapping the floor bounce is
to eliminate the excess buildup of time delayed pressure signal
right near the woofer diaphragm. Especially important is that the
conversion of Kinetic to Potential Energy does not happen unless
the two wavetrains are of equal strength. By weakening one over
the other, the Kinetic Energy of the other is never converted to
Potential Energy and remains unfelt by the woofer.