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COMMERCIAL AUDIO
SPECIFICATIONS
Performance
Frequency Response (at line out): 20 Hz to 20
kHz +/- 1 dB.
Signal to Noise Ratio (master volume at
minimum): 100 dB.
THD: 0.05% typical with 800 mV balanced
input, 1V output.
Input Sensitivity (volts RMS for full output at
maximum gain):
Balanced mic inputs: 3 mV.
Balanced line inputs: 800 mV.
RCA connectors: 400 mV.
Input Impedance (nominal):
Mic: 400 ohms.
Line: 100 kilohms.
RCA: 50 kilohms.
Crosstalk (all controls at “10”): –50 dB at
1kHz.
Line Output Level (nominal): 1.2 V into 10
kilohms.
Phantom Power: 15 VDC.
AC Line Voltages Available:
100V 50/60 Hz
120V 60 Hz
220V 50/60 Hz
230V 50/60 Hz
240V 50/60 Hz
Operating Temperature/Humidity: 0° C to 40°
C at 95% relative humidity (non-condensing).
Storage Temperature: –20° C to 85° C.
Front Panel Controls and Indicators
Power Switch: Pushbutton on-off switch.
The power switch does not affect the 24V DC
auxiliary power input.
Input Volume Controls: Microphone/line, four
in 14M, eight in 28M. Detented potentiometers
with knobs.
Tone Controls: Bass and Treble non-detented
potentiometers on each input channel. Bass
±10 dB at 100 Hz, Treble ±10 dB at 10 kHz.
Power Indicator: Blue LED indicates power on.
Input Signal Presence Indicator: Green LED,
one for each input channel, illuminates when
input signal exceeds –24 dBu (line) or –70 dBu
(mic).
Output Signal Presence Indicator: Green LED,
one for each output channel, illuminates when
output signal level exceeds 100 mV.
Clip Indicators: Red LED, one per output
channel. Illuminates at threshold of audible
distortion.
Output Volume Controls: One per output chan-
nel. Detented potentiometer with knob.
Back Panel Controls and Connectors
Fuse: Protects the power supply.
AC Power Inlet: Detachable IEC.
Auxiliary Power Input: 2-position terminal strip
for 24 VDC (±10%) backup power. Accepts up
to 10 AWG terminal forks.
Mixer Config Switch: A DIP switch with two
functions:
1. Assigns an input as the priority input for
each output, thereby temporarily muting the
remaining inputs. Muting is activated by contact
closure.
2. Global enable switch for phantom power.
Does not affect RCA inputs. Default position
is off.
Priority Connector: 3-pin Phoenix-type connec-
tor allows Input 1 or Input 5 (28M only) to mute
other input signals by contact closure.
Input Routing Switch (28M only): DIP switches
that assign each input signal to each output.
Two switches per input.
Line Out Connector: One 3-pin balanced Phoe-
nix-type connector per output channel. Level
controlled by master volume control.
Input Connectors:
Mic/Line Connector: 3-pin Phoenix-type, bal-
anced, one per input channel.
Dual RCA Input Connector: For stereo music
signals, unbalanced, summed together, two
connectors per input channel.
The tone generator has been omitted. Call
Crown Tech Support if you have a tone genera-
tor question.
Mic/line Switch: Selects mic-level or line-level
signals. One switch for each balanced input
Included Accessories
Power cord
Detachable rack ears
Phoenix-type connectors
Spade lugs
Dimensions
EIA Standard 19-inch (48.3-cm) rack mount
width (EIA RS-310-B) with rack ears, 1.7-inch
(4.3-cm) height and 10.7-inch (27.18-cm) depth
behind the mounting surface.
Weight
Net Weight:
14M: 8.7 lb (3.9 kg)
28M: 8.7 lb (3.9 kg)
Shipping Weight:
14M: 14 lb (6.4 kg)
28M: 14 lb (6.4 kg)
Regulatory Certifications
T
he Crown
®
14M and 28M are high-value mixers for commercial and industrial audio. The mixers
are part of Crown’s Commercial Audio Series, which also includes mixer-amplifiers and power
amplifiers. These low-cost units provide all necessary features in a simple building-block format. Some
applications include schools, hospitals, factories, restaurant/retail, houses of worship, fitness facilities,
A/V boardrooms, correctional facilities, and small offices. Typical uses are paging, background music,
security and evacuation instructions. Input routing allows each input to be assigned to any output. You
can add more mixers for more inputs, or add more power amps (or mixer-amps) to handle more zones.
Other features include priority muting and phantom power.
12/07 138119-1D