SETTING UP THE S•3-way USING A REAL TIME ANALYZER
SETTING UP THE S•3-way USING A REAL TIME ANALYZER
A REAL TIME ANALYZER (RTA) is an especially useful tool for setting up your crossover, as it will
enable you to set parameters like DELAY and LEVEL more accurately. Some Audio Engineers can use
their ears to tune a loudspeaker system. Some will even use the crossover to create the over-all system
curve using the crossover like an equalizer. For the rest of us, an accurately set crossover with a flat
response is the best way to start and using a RTA is the best way to get there.
Using the RTA to Set DELAY Time.
In the real world, no single or multiple speaker system is perfect. If there were such a perfect system, it
would more than likely be comprised of a single transducer that alone could faithfully reproduce the entire
frequency spectrum. Because no such system exists we have to deal with the problems associated with
multiple transducers. The first problem that you will encounter, whether you know it or not, is time travel.
That’s when the S• 3-way’s delay circuit becomes especially useful.
Ideally, the sound reproduced by each driver in the loudspeaker system would be traveling through the
air ultimately reaching the listeners at the same time. To accomplish this in a system using multiple dri-
vers or enclosures, the voice coils of all the drivers would have to be lined up on the same vertical axis.
This is very difficult to achieve in many cases because of the physical size of the different components,
and the position of the drivers in their enclosures. It is not uncommon to have a physical distance of 2” to
24" or more between the low and high frequency drivers. For example, front loaded low frequency dri-
vers and compression drivers mounted on a large horn. With no correction, the low frequency signal can
be traveling through the air 2" to 24" in front of the high frequencies and thereby reaching the listeners at
different times. Although the delay time between the low and high frequency signal may be relatively
small, the negative effects can be substantial. The problem is that both drivers are reproducing frequen-
cies at and around the crossover point, which arrive at the listeners at different times. Typically, the
resulting problem is comb filtering or cancellations at the crossover frequencies.
The S• 3-way features a DELAY control allowing you to dial up-to 2 milliseconds of delay. By using a
RTA and the S•3-way’s DELAY you can time align the drivers in your system and minimize the possibili-
ties of comb filtering. Now follow these steps, separately, for both the left and rights sides of your loud-
speaker:
• Set the crossover to the desired frequencies and press all the Mute switches to the ON position,
turning all of the S •3-ways outputs off. Position your measurement microphone approximately
15 feet from your loudspeaker array, halfway between the low and high frequency drivers. Now
turn all the GAIN controls to the fully counter clockwise position.
• Play a sign wave tuned to the crossover frequency, or connect a pink noise generator to your
loudspeaker system either from your mixer or in the S •3-way’s input. Now turn off the Low
Frequency Mute switch and adjust the S• 3-way’s INPUT GAIN to "0”. Adjust the LOW GAIN
control so that the signal is playing at a loud, but not too painful level. Make sure you only hear
sound from the low frequency driver.
• Adjust the level control of the RTA until it reads OdB at the crossover frequency. Now press the
LOW MUTE switch turning off the low frequency output.
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