Inter-Sample Voltage Peak Limiter Threshold (Isvpl Threshold); Inter-Sample Voltage Peak Limiter Profile (Isvpl Profile); Maxpeak Level (Maxpeaklvl); Maxrms Level (Maxrmslvl) - Lab.gruppen PLM series Operation Manual

9. Front Panel Interface

9.13.2.5.1 Inter-Sample Voltage Peak Limiter Threshold (ISVPL Threshold)

The purpose of the ISVPL is to prevent the voltage at the PLM's output terminals exceeding a pre-
determined value. Selecting ISVPL (soft button 2) permits adjustment of the configured threshold value, in
the range 17.8 V to 193 V. (Note this represents an instantaneous peak voltage, not the RMS value of the
output signal.) Within block parentheses, the actual value is displayed. The actual value can be limited by
the maximum voltage a particular PLM Series model can produce.

9.13.2.5.2 Inter-Sample Voltage Peak Limiter Profile (ISVPL Profile)

Selecting the ISVPL Profile will optimize the ISVPL limiting for the specific frequency band. Selecting ISVPL
Profile (soft button 3) permits individual adjustments per channel between two profiles; Universal and Sub/
LF. The ISVPL Profile affects attack and release times for the ISVPL limiter and Voltage Clip feedback.
Universal is default for PLM 10000Q and Sub/LF is default for PLM 14000.
The remainder of the limiter adjustments refer to the
LimiterMax within the Lake processing system,
which features control of both peak and RMS levels,
referred to as MaxPeak and MaxRMS respectvely.
Full details of the operation of LimiterMax can be found in
chapter 5.2.3 of the Lake Controller User Manual.

9.13.2.5.3 MaxPeak Level (MaxPeakLvl)

This sets the maximum peak signal level at the Processor's Module outputs. It is adjustable from -30 dBu to
+30 dBu in 0.1 dB increments. The MaxPeak level parameters may also be adjusted from the Lake Control-
ler software.
The Group Sum value is also displayed (in brackets) for this parameter for each channel.

9.13.2.5.4 MaxRMS Level (MaxRMSLvl)

This sets the maximum RMS signal level at the Processor's Module outputs. It is adjustable from -30 dBu
to +30 dBu (the default setting unless another range has been specified in the Module settings) in 0.1 dB
increments. The MaxRMS level parameters may also be adjusted from the Lake Controller software.
The Group Sum value is also displayed (in brackets) for this parameter for each channel.

9.13.2.5.5 MaxRMS Corner (MaxRMSCor)

The transfer curve of the RMS section of the Lake LimiterMax is selectable to "soft-knee" or "hard-knee"
characteristic. With a "soft-knee" curve, limiting is gently increased as signal level approaches the threshold,
whereas with a "hard-knee" curve, full limiting is applied to any signal exceeding the threshold by any
amount, but none to signals below the threshold. The Corner parameter is selectable in 0.1 dB increments
from -100 dB to 0 dB (the default setting unless another range has been specified in the Module settings),
this figure representing the level below the limiter threshold at which compression commences. Thus, the
greater the value (negatively), the "softer" the knee. A setting of 0 dB implies a "hard-knee" characteristic.
The LimiterMax Corner parameter may also be adjusted from the Lake Controller software.

9.13.2.5.6 MaxRMS Attack (MaxRMSAtk)

This sets the attack time of the MaxRMS limiter. It is selectable in 0.1 ms increments from 1 ms to 500 ms
which is the default setting unless another range has been specified in the Module settings. The attack time
parameters may also be adjusted from the Lake Controller software.
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PLM Series Operation Manual rev 1.1.3