Operation Manual

11. Operation and performance
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D SERIES Lake Operation Manual rev 3.0.4
11. Operation and performance
22
D SERIES Lake Operation Manual rev 3.0.3
11.3.1. Inter–Sample Voltage Peak Limiter (ISVPL)
The ISVPL is a high quality voltage limiter that can deliver seamless limitation to any desired level. It ensures that
the voltage at the output terminals never exceeds the dened threshold. It operates on these principles:
• The signal is delayed slightly to allow the ISVPL to look–ahead and reduce the gain before voltage in excess
of the threshold can appear at the output. This results in zero voltage overshoot at the output with a rounded
limitation up to the threshold.
• The amplitude of the output signal between digital samples is predicted which permits the ISVPL to respond to
analog peaks that may occur at the digital to analog converter.
• The release time of gain reduction is adaptive depending on the dynamics of the signal. It is possible to select
different ISVPL proles for limiting optimization for a specic frequency band and personal preference. The
proles are divided into two categories, with one category optimized for low distortion and the other focusing
on producing high sound pressure level (SPL). Within each category there are proles optimized for the different
frequency bands.
11.3.1.1. Low Distortion Profiles
• Universal – The universal prole is a soft limiter that can be used for all frequencies and is conservative in its
action upon VCL and CPL.
• Sub/LF – The Sub/LF prole is tuned for frequency bands below 600 Hz. It has longer attack and release times
and is less conservative when it comes to acting upon VCL and CPL.
11.3.1.2. High SPL Profiles
High SPL proles do not use the adaptive release time feature. High SPL proles optimized for high frequencies
use less of the look–ahead delay peak–rounding feature; this feature is used most in the Sub prole and least the
HF prole.
• Sub – The Sub prole is optimized for frequencies between 20 – 200 Hz
• LF – The LF prole is optimized for frequencies between 20 – 1200 Hz
• MF – The MF prole is optimized for frequencies between 300 – 6000 Hz
• HF – The HF prole is optimized for frequencies above 1 kHz
11.3.1.3. ISVPL Voltage Settings
The ISVPL threshold may be set at any level between 17.8 V and 600 V in the Lake Controller software. For further
details, please refer to the Lake Controller User Manual.
Lake–enabled amplier devices (D Series Lake, PLM+, PLM) that have a smaller peak output voltage capability still
allow ISVPL speaker threshold settings up to 600 V. When a threshold is set above the current maximum capability
of a power output channel, the actual ISVPL will automatically be set to the maximum ISVPL for that channel.
Therefore, the ISVPL threshold can be set at the Module for the speaker’s maximum capability, and the Module le
remains cross–compatible with all Lake–enabled amplier devices.
Table 11.3 shows the theoretical maximum output power based on only the load impedance and
the ISVPL setting. See the Technical Specications, or use CAFÉ, to nd the available power for a specic
amplier and load.