Meyer Sound HM-1 User Manual

FEATURES

HM-1

Self-Powered Loudspeaker

Bi-amplified

Integrated electronics

Dual-concentric drivers

Full-range response

R

(42Hz - 20kHz)

15

Phase corrected to 15 kHz

kHZ

U

Magnetically shielded

48 VDC powered

48

VDC

Superior
engineering
for the art
and science
of sound.

The Meyer Sound HM-1 is a
very compact, full-range self­powered loudspeaker system
designed to serve in a wide
variety of installed sound
reinforcement and repro­duction 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 half­space loading. The concentric
tweeter mounting structure is
optimized to minimize both
back-wave interference and IM
distortion. A constant­directivity high-frequency horn
affords a 100° beam width, and
sophisticated phase-correction
circuitry assures true point­source performance without
the off-axis cancellation effects
that plague customary dual­concentric 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 signal­processing circuits are
designed to tolerate supply
voltage drops of up to 15%,
accommodating light-gauge

cables and long cable runs.
Internal energy storage circuits
minimize the system’s peak-to­average 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 concentrically­mounted 1" soft-dome high
frequency driver with constant­directivity 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

PATENT PENDING

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 factory­installed mounting config­urations 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

Meyer
Sound

U

L

C

U

L

®®

LISTED

3K59

COMMERCIAL

AUDIO SYSTEM

HM-1 SPECIFICATIONS

12.3

17.5

9.3

OPTIONAL HM-1 SUBWOOFER

Acoustical

(each loudspeaker)

Coverage

Transducers

Dual-Concentric

Drivers (magnetically

shielded)

Audio Input

Amplifiers

AC-Power

Physical

1

Frequency Range

Half-space

Free Field with Subwoofer

Phase Response

Maximum SPL

Off-axis Amplitude Response

Signal to Noise Ratio

Free Field

Crossover

2

42 Hz - 20 kH
±2.5 dB 100 Hz – 20 kHz; –6 dB 42 Hz – 100 Hz

3

±2.5 dB 90 Hz – 20 kHz; –3 dB 42 Hz – 90 Hz

4

±2.5 dB 42 Hz – 20 kHz

5

±20° 250 Hz – 15 kHz

6

Without Sub: 116 dB SPL; With Sub: 120 dB SPL
±3.5 dB 100 Hz – 20 kHz up to 45° coverage

2

7

Complex roll-off shape, ≈ 3 kHz equal acoustic amplitude
>100 dB (A-weighted noise floor to max SPL)

Meyer Sound Laboratories

has devoted itself to

designing, manufacturing,

and refining components

that deliver superb sonic

reproduction. Every part of

(-6 dB points)

Low Frequency

High Frequency

Subwoofer (optional)

Connector

Impedance

XLR Wiring

RF Filter

Common Mode Rejection Ratio

Output Power

THD, IM, TIM

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

Type

Differential balanced input circuit

8

10 kΩ differential (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

Type

Complementary MOSFET output stages class A/B, bridged
400 Watts RMS, 200 Watts/channel at 4 Ω (with subwoofer)
<.02 %

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.

Voltage
Current

Dimensions

Weight

Protective Grill

Enclosure/Finish

Nominal: 48 VDC; Maximum: 52 VDC; Minimum: 35 VDC;

9

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

Meyer strives for sound

quality that is predictable

and neutral over an

extended lifetime and

across an extended range.

Notes

PHYSICAL DIMENSIONS

ALL UNITS IN INCHES

8.4

6.75

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.

0.6 0.7

8.4

11.0

8.4

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%.

8.4

1.5

Rear Panel

TopSideFront

Made by Meyer Sound, Berkeley, CA, USA

European Office:

Meyer Sound Europe
Dalston House
39-49 Hastings Street
Luton Bedfordshire
England, LU1 5BE

HM-1 - 04.039.002.01B

Meyer Sound Laboratories, Inc.

2832 San Pablo Avenue
Berkeley, CA 94702
tel: [phone]
fax: [phone]
e-mail: [e-mail]
http: www.meyersound.com

© 1998 Meyer Sound Laboratories, Inc.

All rights reserved