System Description - PMC twotwo.5 User Manual

System Description

The electronic heart of the twotwo series
active monitor is a powerful DSP engine
which operates at a fixed sample rate of
96kHz.
Balanced and unbalanced analogue inputs
are conditioned by a low-noise gain stage
prior to A-D conversion, to optimise the
signal-noise ratio. The converter is a very
high quality delta-sigma device, producing
a 24-bit, 96kHz output. The AES3 digital input
can accept sample rates up to 192kHz
and is sample rate converted to 96kHz
automatically.
The DSP engine provides the overall system
volume control, 24dB/octave precision
crossovers, driver optimisation, and driver
Analogue
Gain
input
stage
Adust level
XLR or RCA/
to utilise full
phono
scale of A/D
Digital
input
AES3 XLR
32-192kHz
Volume, EQ,
crossover and
protection
A/D
DSP
24-bit
converison
SRC
Sample rate
conversion
protection. This sophisticated digital signal
processing ensures perfect matching between
the two drivers' responses and roll-off rates,
optimising the contribution of each driver,
minimising distortion, and providing a flatter and
more natural balance over the widest possible
listening area.
The DSP system outputs are converted back to
analogue to feed two separate Class-D power
amplifiers and their respective drivers.
A total of 200W of high-efficiency amplification
is provided, with 50W for the tweeter and
150W for the bass unit. The amplifier design
ensures that driver impedance variations with
frequency are fully compensated to maintain
a uniform frequency response.
DAC
Conversion to
analogue for
amplification
HF AMP
LF AMP
Individual
power amps
for HF and LF
drivers