Appendix B: Connections
“XLR” Connectors
The HD1221 has one female XLR input that accepts
a balanced line-level signal. When connecting a balanced
signal, be sure it’s wired per AES (Audio Engineering
Society) standards:
XLR
Pin 1 – Shield (Ground)
Pin 2 – Hot (+)
Pin 3 – Cold (–)
There is also a male XLR connector on the HD1221
labeled LOOP OUT. This is also wired according to the
AES standards listed above.
Balanced XLR Connectors
The LOOP OUT connector allows you to connect
several HD1221s. Simply plug the signal source
(i.e., mixer output) into the input jack, and patch that
speaker’s LOOP OUT jack to the next speaker’s input
jack, and so on, daisy-chaining multiple speakers. See
below for a visual example of daisy-chaining.
There is a limit to how many HD1221s may
be daisy-chained together. A general rule
is to maintain a load impedance ten times
or more than the source impedance to
prevent excessive loading on the source. For example, if
the mixer has an output impedance of 120 , then you
can daisy chain up to nine HD1221s. This is a load of
1222
(HD1221 input impedance=11 k ; 9 of these in
parallel=1222
). Since microphones typically have a
higher output impedance, you should limit
daisy-chaining from a mic source to two HD1221s.
The LOOP OUT jack is wired straight from the main
input connector — there is no electronic circuitry
between — so the signal coming out of the LOOP OUT
jack is exactly the same as the signal going in.
DAISY-CHAINING MULTIPLE HD1221
S
POWER
LIGHT ON
MAIN
INPUT
LOOP
OUT
LEVEL
+
HD1221
2-WAY HIGH DEFINITION POWERED LOUDSPEAKER
VOICING MODE
POWER
ON
REVISION
PARALLEL
POWER
LIGHT ON
MAIN
INPUT
LOOP
OUT
LEVEL
+
HD1221
2-WAY HIGH DEFINITION POWERED LOUDSPEAKER
VOICING MODE
POWER
ON
REVISION
PARALLEL
POWER
LIGHT ON
MAIN
INPUT
LOOP
OUT
LEVEL
+
HD1221
2-WAY HIGH DEFINITION POWERED LOUDSPEAKER
VOICING MODE
POWER
ON
REVISION
PARALLEL
POWER
LIGHT ON
MAIN
INPUT
LOOP
OUT
LEVEL
+
HD1221
2-WAY HIGH DEFINITION POWERED LOUDSPEAKER
VOICING MODE
POWER
ON
REVISION
PARALLEL
Mixing Console
(Mackie 1604-VLZ3 shown)
to next
speaker
L/R
MAIN
OUT
to next
speaker
15
Owner’s Manual
Owner’
s Manual
