Nexo NXAMP User Manual download pdf (Page 16)

ENGLISH

PAGE 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.

ANALOGUE AND DIGITAL

TDCONTROLLER 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

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Nexo NXAMP User Manual Page 16