AS-EQ1 Operator Manual
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Appendix A - Why EQ?
subwoofer(s), effectively quieting the artificially boosted frequency. In some (but not all) cases, other fre-
quencies that have had their energy decreased due to cancellation will now appear louder due to the reduction
of boosted frequencies and will be easier to hear. In some cases decreased frequencies can be boosted to
make them louder, however in other cases no amount of boost will effectively increase a range of frequencies
if they are being cancelled by a reflection of the original frequency.
The graphs shown below are an example of a room before and after applying electronic EQ. You can clearly
see in the two Subwoofer examples how boosted frequencies have been cut, and where possible, decreased
frequencies have been boosted.
All of these methods, if done effectively, have historically required professional help along with specialized
tools and techniques to achieve better results in a room. The audio and home theater enthusiast developed
manual measurement techniques using inexpensive Sound Pressure Level (SPL) Meters, Excel Spreadsheets
and test tone CDs, along with Graphic and Parametric Equalizers to attempt to correct their listening environments.
In some cases people found they could hear and see improvements, and in just as many cases only minor
improvements would be seen. In any case however, manually EQing a room is a labor-and-time intensive
activity, and in many situations a pure “labor of love”.
FIG. 22
