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TSS-SUB4000
Example 2. T
wo Response Peaks:
Characterized by two response peaks, approximately equal in
amplitude and width.This requires that you make a choice
between the two peaks. In situations like this, the higher
frequency peak will always be more audible and objectionable.
Response peaks below 45Hz, unless extreme, can actually be
beneficial toward achieving visceral impact. Perform corrections
on the upper frequency peak.
Apply the Width Selector as described above.Align the center-line
of the Selector over the center of the higher frequency peak.Now
adjust the Selector until you have achieved the “best fit.”The
slider now points to the correct width setting. In this example,
this is at 52Hz.The best-fit width is 28%. Fill in the Width and
Frequency fields provided on the template.
Determine the appropriate level using the technique described
earlier.This calculation will indicate a –8dB setting. However, this
peak does not reach the 0dB level as the lower peak does.
Therefore, a –8dB setting would be excessive.The 52Hz peak
stops at –2dB. Subtracting 2 from 8 yields the correct setting,
–6dB. Enter –6 in the Level field.
Skip to the “Adjusting the R.A.B.O.S. Equalizer”section on page 14.
Example 3. P
eak Adjacent to a Dip:
Response dips can occur at any frequency, sometimes
immediately adjacent to the peak you w
ant to cor
r
ect.
T
wo
e
xamples ar
e shown,
one immediately above and one immediately
below the peak. Deep response dips such as these are caused
by destructive wave interference. Destructive interference dips
occur only in one spot within the room. It is not uncommon to
completely eliminate the eff
ect by mo
v
ing the RSLM to a different
location. Note that this does not eliminate the dips.We have simply
moved away from them. Sometimes only a few inches are required.
Do not attempt to correct this condition with equalization. If you
encounter dips like this
,
take the f
ollowing steps:
1. Select a new test position: Cue the test track corresponding to
the center fr
equency of the dip
.
In the f
ir
st e
xample in F
igur
e 19,
you would pla
y
T
r
ack 13 (56Hz).
Pr
ess
Pla
y
›
.
Y
ou will see a
reading very close to what you had before. Now, slowly move the
RSLM around the area, if possible remaining within about a foot
of the original test point.As you move the RSLM, watch the bar
graph.You will observe large level fluctuations. Find a position
that restores the level to approximately that of the adjacent test
points.You may find it helpful to move the RSLM vertically. Dips
can be oriented in any axis.The position that restores the level to
about that of the adjacent test points is your new test position.
Figure 18. Dip above or below peak
F
igure 17.Two response peaks