Table of Contents
Advertisement
CHAPTER 3: AMPLIFICATION AND AUDIO
Audio Loop Output (XLR 5-Pin Male)
The XLR 5-pin male Loop output connector allows multiple
loudspeakers to be looped from a single audio source. The
Loop output connector uses the same wiring scheme as the
Input connector (see "Audio Input (XLR 5-Pin Female)" on
page 11). For applications that require multiple LEO-Ms,
connect the Loop output of the first loudspeaker to the Input
of the second loudspeaker, and so forth.
NOTE:
The Loop output connector is wired in
parallel to the Input connector and transmits
the unbuffered source signal even when the loud-
speaker is powered off.
Calculating Load Impedance for Looped Audio
Signals
To avoid distortion when looping multiple loudspeakers,
make sure the source device can drive the total load imped-
ance of the looped loudspeakers. In addition, the source
device must be capable of delivering approximately 20 dBV
(10 V rms into 600 ohms) to yield the maximum SPL over the
operating bandwidth of the loudspeakers.
To calculate the load impedance for the looped loudspeak-
ers, divide 10 kOhms (the input impedance for a single loud-
speaker) by the number of looped loudspeakers. For
example, the load impedance for 10 LEO-Ms is 1000 ohms
(10 kOhms / 10). To drive this number of looped loudspeak-
ers, the source device should have an output impedance of
100 ohms or less. This same rule applies when looping
LEO-Ms with other Meyer Sound self-powered loudspeak-
ers.
NOTE:
Most source devices are capable of
driving loads no smaller than 10 times their
output impedance.
TIP:
Audio outputs from Meyer Sound's
Galileo 616 and Galileo Callisto 616 are rated at
50 ohms, which means that their outputs can singly
drive up to 20 Meyer Sound (10 kOhm) loudspeakers
without distortion.
CAUTION:
Make sure that all cabling for
looped loudspeakers is wired correctly (Pin 1
to Pin 1, Pin 2 to Pin 2, and so forth) to prevent the
polarity from being reversed. If one or more loud-
speakers in a system have reversed polarity, fre-
quency response and coverage will be significantly
degraded.
12
CABLE RINGS
Two cable rings are provided on the rear of the LEO-M cabi-
net. Power and audio cables should be tied off to the rings
to reduce strain on the cables and prevent damage to them
during installation. The cable rings should not be used for
any other purpose.
Cables Tied Off to Cable Ring
CAUTION:
LEO-M cable rings should only be
used to reduce strain on cables. The cable
rings should not be used for any other purpose.
TRUPOWER LIMITING
LEO-M employs Meyer Sound's advanced TruPower
ing. Conventional limiters assume a constant loudspeaker
impedance and set the limiting threshold by measuring volt-
age alone. This method is inaccurate because loudspeaker
impedances change as frequency content in the source
material changes, and as thermal values for the loud-
speaker's voice coil and magnet vary. Consequently, con-
ventional limiters often begin limiting prematurely, which
reduces system headroom and dynamic range.
In contrast, TruPower limiting anticipates varying loud-
speaker impedances by measuring both current and voltage
to compute the actual power dissipation in the voice coil.
This improves performance, both before and during limiting,
by allowing the driver to produce the maximum SPL across
its entire frequency range, while also retaining signal peaks.
TruPower limiting also eliminates power compression at high
levels over lengthy periods, which helps regulate voice coil
temperatures, thereby extending the life of the driver.
®
limit-
Hide quick links:
Advertisement
Table of Contents
