QSC KW153 [17/28] High frequency eq

High-frequency EQ

On the KW122, KW152 and KW153 there are two high-frequency settings. From the factory, the

switch is set to FLAT. This means that the loudspeaker system is producing a ﬂat response through

the vocal band. This is the standard setting for most applications.

In voice-only reproduction, the switch can be set to the VOCAL BOOST setting. This will engage EQ

that gives a stronger presence for vocal intelligibility and presence. It is generally not recommended

to use this setting when playing full-range music through the system.

Subwoofer Polarity

Polarity (sometimes improperly referred to as phase) refers to the voltage of an input signal and

whether it is a positive or negative voltage at any given time. In most cases a positive voltage

causes a woofer cone to move forward with respect to the cabinet orientation, and a negative

voltage then moves the woofer cone backward. Most importantly, speakers reproducing the same

signal or signals that are adjacent in frequency must have the same polarity to get the maximum

output. This is most important for low frequencies. Polarity can be altered by incorrect wiring or

mixer control settings.

The KW181 provides a polarity switch to correct any wiring or mixer setting errors. The polarity

switch is set in the NORMAL position from the factory.

When using the KW181 with KW Series full range loudspeakers, NORMAL polarity will result in the

best bass response if the full range loudspeakers are sitting on or very close to the subwoofers. If

the subwoofers are some distance away from the full range loudspeakers, polarity change may be

of beneﬁt. Start with all subwoofer POLARITY switches in the NORMAL position. Then, with the

system at or near expected operating levels, change the polarity of each subwoofer individually.

Walk around the venue and assess the overall bass response. Select the polarity that results in the

best overall system bass response.

When using only one KW181 and connecting a LEFT and RIGHT stereo signal, start with the polarity switch in the NORMAL position. With the system

at a reasonable level, change the POLARITY switch and evaluate which polarity results in the most low-frequency output.

KW122, KW152, KW153 High-frequency

EQ Switch

KW181 Polarity Reversal Switch