Owner's Manual

Parasound
®
ZoneMaster
™
2350 Owner’s Manual Page 12
High Pass Filter Switch
Using the High Pass Filter can improve the sound in many installations. It’s called a “high pass” filter because
depending on the switch position it permits signals higher than 30 Hz or 80 Hz to pass, while preventing signals
below these frequencies from passing. There are three positions for this switch:
Off: The Off setting bypasses the filter so the Model 2350’s frequency response is full range (flat).
30 Hz: The 30 Hz setting filters out frequencies below 30 Hz at 12 dB per octave. Most speakers will have
greater dynamic range and far less distortion when they don’t receive frequencies which are lower
than they are capable of reproducing. There are very few in-wall or in-ceiling speakers capable of
reproducing frequencies below 30 Hz. Engaging the 30 Hz high pass filter will keep the speakers from
being over-driven, allowing them to play louder without distortion.
The 2350 will also operate more efficiently when it’s not called upon to amplify very low frequencies so
you’ll have more power in the frequency range the speakers are capable of reproducing. Because the
30 Hz setting is essentially a sub-sonic filter you probably won’t notice any loss of low bass information
unless you’re using very large full range speakers.
80 Hz: The 80 Hz setting filters out bass below 80 Hz at 12 dB per octave. This setting is advised when
the 2350 is driving in-wall or in-ceiling speakers in conjunction with a separate subwoofer. Most in-
ceiling and in-wall speakers have little useful bass output below 80 Hz. You’ll enjoy much cleaner
sound and higher undistorted volume levels with these lower frequencies filtered out.
Note: Typical volume controls for in-wall or ceiling installed speakers use stepped
autoformers. Autoformers impose a highly reactive load on the power amplifier often
stress it, leading to malfunction. The 30 Hz or 80 Hz filter settings enable the 2350 to
drive any such volume control with ease.
Note: Most speaker selector boxes use passive volume controls with autoformers with the
same challenges for most amplifiers.
A/B Speaker Selector Lockout Switch
The Lockout switch lets the home owner or installer disable the front panel A and B speaker selector buttons.
In some installations the A/B buttons are useful to turn the audio on/off in a second room or zone. In other
installations you may always want the A and B speaker outputs to be on. The Lockout switch prevents the
buttons from turning off the speakers by mistake. There are two options to this switch:
Normal: When this switch is set to Normal, the front panel A and B buttons determine whether speaker
output terminals A and B are live. If both front panel A and B buttons are turned off there will be no
sound from any speaker. Use the Normal option only if you or your client intend to use the front panel
A and B buttons.
Lockout: When this switch is set to Lockout, the front panel A and B buttons are disabled so speakers
A and B will always be on, even if the front panel A/B buttons are turned off. This feature can be
particularly useful for a professional audio installer who never intends for the client to use the front
panel Speaker A/B buttons. Select the Lockout option only if the front panel A and B buttons won’t be
used.