Meyer Sound Self-Powered Loudspeaker HM-1 User manual

48VDC
U
15
kHZ
cables and long cable runs.
Internal energy storage circuits
minimize the system’s peak-to-
average supply current
demands, allowing efficient
use of switched-mode
regulated supplies.
The HM-1 is a two-way
system comprising a 7”
graphite cone low-frequency
driver, and a concentrically-
mounted 1" soft-dome high
frequency driver with constant-
directivity horn, in a vented
cabinet. Integral bi-amplifiers
affording 400 Watts total
power output are built into the
enclosure, along with an active
crossover, driver protection
voltage limiters, and frequency
and phase response alignment
circuitry. A laser-trimmed
differential input stage affords
superior common-mode
The Meyer Sound HM-1 is a
very compact, full-range self-
powered loudspeaker system
designed to serve in a wide
variety of installed sound
reinforcement and repro-
duction applications.
The HM-1 incorporates
significant design innovations
that afford unprecedented
performance with practical
advantages. In contrast to
conventional small speaker
systems, the cabinet venting is
tuned at 40 Hz to provide flat,
full-range response with half-
space loading. The concentric
tweeter mounting structure is
optimized to minimize both
back-wave interference and IM
distortion. A constant-
directivity high-frequency horn
affords a 100°beam width, and
sophisticated phase-correction
circuitry assures true point-
source performance without
the off-axis cancellation effects
that plague customary dual-
concentric designs.
By implementing distributed
amplification, the HM-1 affords
substantial advantages in
reliability and ease of
installation when compared
with constant-voltage (70 V)
distributed systems. The HM-1
accepts a unipolar 48 VDC
power source which may be
supplied using twisted-pair
wiring jacketed with the signal
source conductors, eliminating
the need for wiring conduits
and greatly reducing induced
noise. Its amplifier and signal-
processing circuits are
designed to tolerate supply
voltage drops of up to 15%,
accommodating light-gauge
FEATURES
rejection to accommodate
simple twisted-pair signal
distribution. Front-panel LEDs
indicate power, signal limit,
and thermal overload, and
a rear-panel circuit breaker
provides overall DC
power protection.
The magnetically shielded
HM-1 enclosure is coated with
a textured black or white
finish, and a variety of factory-
installed mounting config-
urations may be ordered.
Optional accessories include a
remote switched-mode power
supply, a variable-speed
cooling fan assembly
controlled from an integral
rear-panel drive output, and an
auxiliary subwoofer that
provides flat response to 42 Hz
in free field and is powered by
the HM-1 low-frequency
Self-Powered Loudspeaker
HM-1
Bi-amplified
Integrated electronics
Dual-concentric drivers
Full-range response
(42Hz - 20kHz)
Phase corrected to 15 kHz
Magnetically shielded
48 VDC powered
R
PATENTPENDING
Meyer
Sound
Superior
engineering
for the art
and science
of sound.

8.4
0.6 0.7
PHYSICALDIMENSIONS
ALL UNITS IN INCHES
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
tel: [phone]
fax: [phone]
e-mail: [email protected]
http: www.meyersound.com
UL
C
UL
®®
LISTED
3K59
COMMERCIAL
AUDIO SYSTEM
Meyer Sound Laboratories
has devoted itself to
designing, manufacturing,
and refining components
that deliver superb sonic
reproduction. Every part of
every component is
designed and built to
exacting specifications
and undergoes rigorous,
comprehensive testing
in the laboratories.
Research remains an
integral, driving force
behind all production.
Meyer strives for sound
quality that is predictable
and neutral over an
extended lifetime and
across an extended range.
Made by Meyer Sound, Berkeley, CA, USA
European Office:
Meyer Sound Europe
Dalston House
39-49 Hastings Street
Luton Bedfordshire
England, LU1 5BE
© 1998 Meyer Sound Laboratories, Inc.
All rights reserved
11.0
8.4
6.75
8.4
8.4
1.5
HM-1 - 04.039.002.01B
Rear Panel
TopSideFront
Acoustical1
(each loudspeaker)
Coverage
Transducers
Dual-Concentric
Drivers (magnetically
shielded)
Audio Input
Amplifiers
AC-Power
Physical
Notes
HM-1 SPECIFICATIONS
Frequency Range2
Free Field
Half-space3
Free Field with Subwoofer4
Phase Response5
Maximum SPL6
Off-axis Amplitude Response
Crossover
Signal to Noise Ratio
(-6 dB points)
Low Frequency
High Frequency
Subwoofer (optional)
Connector
Type
Impedance
XLR Wiring
RF Filter
Common Mode Rejection Ratio
Type
Output Power
THD, IM, TIM
Voltage
Current9
Dimensions
Weight
Protective Grill
Enclosure/Finish
42 Hz - 20 kH2
±2.5 dB 100 Hz – 20 kHz; –6 dB 42 Hz – 100 Hz
±2.5 dB 90 Hz – 20 kHz; –3 dB 42 Hz – 90 Hz
±2.5 dB 42 Hz – 20 kHz
±20°250 Hz – 15 kHz
Without Sub: 116 dB SPL; With Sub: 120 dB SPL
±3.5 dB 100 Hz – 20 kHz up to 45°coverage7
Complex roll-off shape, ≈3 kHz equal acoustic amplitude
>100 dB (A-weighted noise floor to max SPL)
100°H; 100°V
7” graphite cone driver
1” soft-dome tweeter
10” cone driver (not shielded)
Options are 1 female XLR or a pluggable terminal strip
Differential balanced input circuit8
10 kΩdifferential (between pins 2 and 3)
Pin 1: chassis; Pin 2: + signal; Pin 3: – signal
Common Mode: 425 kHz low-pass; Differential Mode:
142 kHz low-pass
>80 dB (50 Hz – 1 kHz); typically 90 dB
Complementary MOSFET output stages class A/B, bridged
400 Watts RMS, 200 Watts/channel at 4 Ω(with subwoofer)
<.02 %
Nominal: 48 VDC; Maximum: 52 VDC; Minimum: 35 VDC;
Typical: 2.0 Arms, 3.5 Apk; Maximum in limiting:
3.0 Arms, 5.0 Apk
Height: 11.0”; Width: 8.4”; Depth: 9.7”, 10.5” with
fan attachment
11.0 lb (5.0 kg); shipping: 13.5 lb (6.1 kg)
Removable perforated steel grill causes < 0.5 dB
response variation
All birch plywood/black textured
1. Measurements are taken at 1 m on-axis, 1/3
octave, unless otherwise stated.
2. Amplitude tolerance depends on loading
conditions and whether the subwoofer is used.
3. Flush-mounted into single boundary surface.
4. Subwoofer adds approximately 8 dB
42 – 100 Hz.
5. Phase variation from pure delay and minimum
phase removed.
6. Pink noise or music.
7. A gradual amplitude attenuation occurs as the
angle increases beyond 45°. Greater attenuation
occurs at 2 kHz and beyond 10 kHz. There are
no response peaks.
8. Capacitively coupled; accepts up to ±50 VDC
common mode.
9. Idle current @ 0.4 A; using the slaved
subwoofer increases stated currents by @ 20%.
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9.3
OPTIONAL HM-1 SUBWOOFER