User's Manual

The PA2’s output POLARITY parameter (located in the crossover) is used to match polarity between drivers. Some multi-way

main speakers will require certain drivers to be polarity inverted when operating in bi-amped mode (bypassing the internal

passive crossover network). When selecting any bi-ampable main speaker from the PA2’s speaker tuning list in the Setup

Wizard, such polarity inversion will be performed for you automatically. If your multi-way main speaker model isn’t listed in the

PA2 and you can’t find tuning information for them, check the loudspeaker’s spec sheet or documentation, or contact the

speaker manufacturer as they will usually be able to provide this information.

If you’re unable to find polarity information for your speakers, or just want to verify your drivers are in phase, you can do some

investigative work using a tone generator or some sine wave tone samples (which can be downloaded for free online). To

do so, take note of the crossover frequency setting used between the drivers being tested and play a sine wave tone of that

frequency through the system.

TIP: Make sure any active AFS modules are turned off before passing sine tones through the PA2. Failing to do so may

cause Live AFS filters to be set.

For example, if you’re testing the woofer and high frequency driver in a bi-amped main speaker cabinet and the active

crossover frequency between the two is set at 2.5 kHz, play a 2.5 kHz sine wave tone through the system. Both drivers will

reproduce the tone simultaneously as long as the crossover frequency is indeed within the range of frequencies both drivers

are capable of reproducing. Stand in the “sweet spot” of the venue (the audience position equidistant from the speakers) and

invert the polarity in the PA2’s crossover for the low output and find out which setting provides the loudest signal level (note

that results are most noticeable if sound pressure levels between the drivers have been matched). The setting which provides

the loudest signal level is the one which is more “in phase” and is the setting you should use. If applicable, perform this same

test, working your way down through the lower-frequency drivers.

Once polarity is matched for all drivers in the system, you’re ready to optimize the driver alignment delays. The “polarity” test

mentioned in the previous paragraph can also be used for determining if driver alignment delay is necessary. Play the selected

sine tone through the system (once again, the sine tone frequency should match the set crossover frequency of the drivers

being tested) and invert the polarity on the lower driver so that the two drivers are out of phase. If necessary, adjust the drivers’

levels until the most phase cancellation is achieved. Try adjusting the driver alignment delay for each driver to see if either

produces more phase cancellation. Set the delay for the most phase cancellation on whichever driver requires it. When done,

set the polarity back for proper phase alignment. Repeat this procedure for the remaining speakers/drivers if applicable. For

more information on setting driver alignment delays, see ‘Delay’ on page 39.

Changes to all these settings can be difficult to judge when heard in the context of the whole system, but by zeroing in on the

specific crossover frequency regions, matching levels, and inverting polarity on one of the drivers, you are free to experiment

with different settings to determine the best settings for your loudspeaker system. Adjust each of these parameters until the

most phase cancellation is achieved then switch the polarity back so the drivers are once again in phase. Optimizing these

parameters using this test will allow your system to work in harmony and improve its magnitude and phase response.

3. Set Gain Structure & Limiters

Now that the crossover settings are optimized and the loudspeaker drivers are in phase, it’s time to calibrate the gain structure

of the system. This will provide ample headroom for all system components in the signal chain and optimize your system’s

signal-to-noise performance.

Your amplifiers play a vital role in system setup, because they are the last devices in the signal chain before your loudspeakers

and offer the greatest amount of gain (that is their job after all). If your amplifiers are setup incorrectly you will not be using