ENGLISH
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16
BLOCK DIAGRAM DESCRIPTION
The Physio control voltage acts independently on the VCA with its operation threshold slightly lower (3
dB) that of the temperature limiter and a low compression ratio; its optimised attack time constant allows
it to start operating without any subjectively unpleasant transient effects.
Interchannel regulation (11)
As described before, each transducer is individually servo-controlled for temperature.
This means in practice that, in case of a potential risk detected, protective operation would only affect the
concerned driver. Your driver will be protected but the overall system tonal balance could be altered if the
different channels are not heating at the same time. In addition, triggering a temperature protection
means that the loudspeaker has already lost some efficiency (power compression up to 3dB in extreme
cases)
The purpose of interchannel regulation is to cancel that effect by linking VCAs together. When the
protection is activated on one channel and reaches a predetermined threshold, the regulation section
begins to correct the balance between the different channels (HF, MF, and LF) by acting on the
concerned VCA.
Peak limiter (12)
The peak limiter primary function is to avoid massive clipping of the amp, which can have some very
audible artefacts.
The threshold of the peak limiter is determined by the user to match its amplifier. See in “ Amplifiers
(Gain, Power)” page 25.
The second function of the peak limiter is to avoid huge amounts of power being sent to a driver. Each
driver is protected in temperature and displacement but there could be other factors of destruction that
cannot be predicted by simulation (especially mechanical damage to the cone…). Each driver is specified
for a certain power handling and a factory set peak limiter threshold is tuned to avoid any abuse.
Delay & polarity inversion (13)
Input to output delay without filtering is 2.2ms (due to the digital processing). The latency time of the
NX241 used to be 1.4ms. Since the LOAD2_21 the latency time of the NX241 has been artificially
extended to 2.2ms to achieve phase compatibility with the NX242 (and so the delay between the 2 units
is less than a sample). For that reason:
Do not mix NX241 with a LOAD earlier to 2.20 with the NX242
This delay will prevent also compatibility with analogue TDcontrollers.
A
NALOGUE AND DIGITAL
TD
CONTROLLER SHOULD NOT BE MIXED IN THE SAME SYSTEM
.
Factory set-up delay
Note that each output may contain a small phase adjustment delay at the crossover point. Also, a polarity
inversion may be performed. These adjustments are part of the factory set-ups and are necessary to
time-align the corresponding cabinet that is selected.
NX242 USER MANUAL LOAD2_22
DATE : 12/3/2004
