Sample Rate Converter (Src); Automatic Fallback Option; Benefits - L-Acoustics LA-AES3 Manuel D'utilisation

5.2.3

Sample Rate Converter (SRC)

The SRC embedded in the LA-AES3 board has been selected to support a wide range of input formats (16-24 bits/
44.1-192 kHz). It converts any of them to the 24 bits/96 kHz format used by the internal clock of the amplified
controller. The SRC is a high-quality hardware component (140 dB dynamic range, THD+N<-120 dBfs, strong input
jitter attenuation) and provides constant propagation delay regardless of the input sampling frequency.
Note: There is no external synchronization mode. The amplified controller's clock always runs using its high-precision
internal quartz at 96 kHz. It ensures low jitter and high audio quality while preserving isophase required for line source
systems.
5.2.4

Automatic fallback option

A fallback option is selectable to prevent sound cut in case of digital signal failure (no clock, loss of lo ck, CRC error,
bipolar encoding error, data slip), switching automatically from AES/EBU to ANALOG inputs.
Seamless switch is available since LA-AES3 allows setting even level and propagation delay for both AES/EBU and
ANALOG signal paths.
After the digital signal has returned to normal state, reverting to the AES/EBU input mode is not automatic and must be
done manually by the user (one click is sufficient for all concerned amplified controllers by using LA NETWORK
MANAGER software).
Note: Invalid audio (validity bit)
A validity bit at non-audio value will not trigger the automatic fallback. Instead the signal will be muted.
5.3

Benefits

Keeping the signal in the digital domain by using the LA-AES3 board will provide the following benefits (with any digital
mixing desk or any audio network) compared to the analog signal distribution:
 Better audio quality by removing one D/A - A/D cycle.
 Better dynamics thanks to the digital links' immunity to ground loops.
 Optimized level chain by removing the risk of level misalignment between console and amplified controllers.
 Digital signal refreshed at each amplified controller in a daisy-chain.
 Improved maximum cable length: tested up to 305 m/1000 ft at Fs = 48 kHz with 3 types of AES/EBU rated
cables (Belden ® 1696A, Klotz Cables
Note: The tests have been done with single cuts of cables. Using several pieces to build a 305 m length cable
will reduce performances.
LA-AE S3_UM_ML _2.0
® OT234H, and Sommer Cable
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® SC BINARY 234).
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