lower noise from the aC mains.
a 96 khz processor replaces the
previous 48 khz processor (offering
higher-frequency bandwidth and lower
latency). The bottom line is, the i-Tech
hd processor is eight times more powerful than its predecessor, with much
of that increased power coming from a
combination of the availability of more
powerful components – such as the
Sharc 21369 dSP chips that are much
more powerful than the 21065 chips
used previously – and better integration
of existing technologies with each other
and within the amplifier design.
contained in
the LevelmaXTm
suite, which was co-developed
with JbL resulting in another 2-3 db
more usable peak SPL from JbL
VerTec arrays.
The Patented Class-I amplifier engine
used in all I-Tech HD amplifiers
CHALLENGE: SMART LIMITING
developing the i-Tech hd was not
without its challenges, such as addressing multiple types of onboard limiting. Peak and RmS limiting require
aggressive yet sophisticated limiting –
the trick is catching that first transient
without squaring it off and making the
sound gritty. however, another type
of limiting is needed to handle long-term thermal issues. The answer was
to integrate dSP-based intelligent and
adaptive limiting, in which attack and
release are based on the actual frequencies each specific channel is passing.
all three limiter systems (peak, RmS
and transducer thermal) are tuned to
work together using either a pre-opti-mized auto mode or a manual mode
to allow advanced users to tweak certain parameters, if necessary. This was
CROSSOVERS
a lot of attention was paid to the finite
impulse response (fiR) filters. They
make the transition between band
passes while maintaining the proper
linear phase relationship and frequency
response. The code for these was developed from the ground up and it was not
a trivial process due to the large amount
of processing power the fiR demands,
versus infinite impulse response (iiR)
minimum-phase filters. The challenge
in using the fiR in a live application is
achieving the steep roll-off rates with
low latency. in order to achieve linear
phase response, a longer delay time is
incurred than would be necessary with
an iiR filter. With fiR filters there is a
direct trade-off in terms of performance
versus latency, but the key is to improve
stop-band rejection.vit’s something
we spent a lot of time refining. This
is where the new Sharc chips really
shine. The Crown algorithm utilizes
the latest fast-convolution ff T technologies in a proprietary manner which
has been optimized for this processor
to deliver the lowest possible latency
with the lowest possible processing
overhead, so you can achieve extreme
crossover roll-off rates with very good
stop-band attenuation – the stop-band
performance is typically 10-20 db better than other dSP products while
reducing the potential for phase rotation between bands and any filter-driver
phase interaction.
The rear panel, showing all connection points of an I-Tech HD amplifier.
OTHER CLEVER STUFF
The i-Tech hd has two fans, one each
for the power supply and the amplifier section, as did its predecessor. but
there is a significant difference. Rather
than having both fans react when either
section of the amplifier topography
required it, each fan in the i-Tech hd
operates independently of the other.
also, each fan’s tachometer reports the
fan speeds to the dSP and will alert the
user if there’s a malfunction.
