PAGE
21/24
PROTECTION INFORMATION NOTES
USER MANUAL LOAD1_80
DATE: 30/08/00 12:48
Physiologic Dynamic Control
The so-called Physiologic Dynamic Control is intended to avoid unwanted effects as a result of a
too long attack time constant. By anticipating the operation of the temperature limiter, it prevents a
high level Audio signal appearing suddenly then being kept up for a period, which is long enough to
trigger the temperature limiter. Without this, a rough and delayed gain variation would result which
would be quite noticeable and unnatural.
The Physio control voltage acts independently on the VCA with its operation threshold slightly
above (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
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
The peak limiter primary function is to avoid massive clipping of the amp, which can have some
very audible artefacts and in some cases may be dangerous for the Cabinets. (Modulation of the
amplifier’s rails can create very low frequencies not filtered at all by the NX241 or some harmonics
at high frequency and level…)
The threshold of the peak limiter is determined by the user to match its amplifier. (3 MENU AMP
POWER and AMP GAIN).
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.
Summary of Contents for NX241
Page 1: ...NX241 DIGITAL TDcontroller User Manual ...
Page 27: ......
