Meyer Sound HIGH DEFINITION AUDIO MONITOR HD-1 User Manual

The HD-1 High Definition

Audio Monitor* is a self-contained,
precision loudspeaker for near-
field sound reproduction.

Aligned to closely approximate

a true point source radiator, the
HD-1 features exceptionally broad
directivity characteristics. Its time
delay response is tightly controlled,
with minimal deviation from linear
phase across the full frequency
range of its operation. Each unit is
individually factory-calibrated to
ensure unprecedented consistency
of performance. The HD-1 is
suitable  for critical applications
ranging from professional record-
ing to psychoacoustical research.

The HD-1 is a two-way system

comprising an 8-inch cone low-
frequency driver and dome tweeter
housed in a vented cabinet. The
low-frequency driver features an
exceptionally large magnet struc-
ture and a 2-inch voice coil for
greatest efficiency and heat dissipa-
tion. The tweeter employs a
specially-developed impregnated
silk dome to minimize breakup and
colorization.

Both drivers are of a proprietary

design, and are individually
selected for maximum linearity.
Their magnet structures employ
sophisticated field-cancelling
design techniques to minimize
magnetic field leakage, and the
cabinets may safely be placed

within 2 feet of sensitive color
video monitors. For applications
requiring closer proximity to
monitors, an optional steel-
shielded model is available.

The HD-1 incorporates line-level

control electronics mounted within
a rear-panel chassis, including:

• an active balanced input circuit

with switchable sensitivity
(+4 dBu or -10 dBV);

• an active crossover utilizing

optimized pole-zero filter
combinations to achieve acousti-
cal transparency and linear
phase;

• independent protection circuits

for each loudspeaker driver;

• dual power amplifiers for

biamplification.

The driver protection circuits

employ thermo-predictive limiters
and soft peak clamps to guard

against damage from excessive
amplifier power and ensure
graceful overload characteristics.

Independent power biamplifiers

maximize system headroom,
efficiency and damping while
minimizing distortion. The low
frequency amplifier delivers 150
watts output power, while the high
frequency amplifier provides 75
watts. Both employ complementary
power MOSFET output stages
operating class A at low-to-moder-
ate listening levels (<90 dB SPL),
and class AB at high levels.

The HD-1’s free-field frequency

response is flat within ±1 dB from
40 Hz to 20 kHz (-3 dB at 32 Hz
and 22 kHz). It delivers high peak
SPL with >100 dB dynamic range
and extremely low distortion.
Covers are included for use during
transport.