Samson E31I - Manual (Page 18)

16
Using the E62i / E31i / E30i
with an RTA (Real Time Analyzer)
An RTA (Real Time Analyzer) is a device which measures the relative levels of multiple
frequency areas. This device, in conjunction with a pink noise generator, is the perfect
companion for your E62i / E31i / E30i. Together with a high quality microphone, these
tools allow you to fine tune the overall frequency response of your audio system in any
given environment (this procedure is sometimes known as “tuning” a room).
To use this kind of system, connect the E62i / E31i / E30i to your mixer’s main outputs or
across main mix output inserts (see pages 8 - 9 in this manual for typical configuration
diagrams). Set the E62i / E31i / E30i Level slider(s) to the center detented “0 dB” position.
Because you’ll probably need to boost as well as cut certain frequencies—and because
you’ll rarely need to make adjustments of more than 6 dB, if you’re using an E62i or E31i,
make sure all Cut Only switch(es) and ±12 dB switch(es) are out (in their up position).
Start by placing all front panel Equalizer sliders at their flat (“0”) center detented position.
Then inject pink noise into your loudspeakers via your mixer at a normal operating level
(make sure the pink noise is loud enough to drown out any ambient noise floor caused by
air conditioners or outside traffic, etc.). Finally, connect a quality microphone to the RTA
and place the mic in a typical listening position. Because pink noise consists of all audible
frequencies blended together at equal level, the RTA should, in theory, show all frequency
bands to be flat. However, due to anomalies in every physical environment, this will rarely
if ever be the case. While watching the RTA, use the front panel Equalizer sliders to make
corrections to the signal, boosting any dips in the measured frequency response and
attenuating any peaks. Repeat the procedure three or four times from different listening
positions, averaging the results if necessary to come up with an equalization curve that
works well at all positions. If you get drastically different measurements at different
listening positions, you may need to reposition various loudspeakers or change the
amount of power applied to some of them.
Bear in mind that an analyzer “listening” to pink noise is no substitute for the human ear
listening to actual program material. A perfectly flat frequency response is not necessarily
the best sounding frequency response, so, once you have used the RTA and the
E62i / E31i to tune a room “by the numbers,” be sure to audition the results by playing
typical audio signal (music, speech, etc.) through your system and continue to fine tune by
ear. Be prepared to compromise—and if there’s a discrepancy between what the RTA
says and what your own ears tell you, always go with the latter.
ENGLISH