Lab.gruppen PLM 20K44 Operation Manual page 81

The improvement in noise performance (at the cost of losing headroom and compression features) is only 0.6 dB;
it is therefore not recommended to optimize performance in this manner.
10.3.3.2. Analog Input Gain Structure Examples
Figure 10.4 illustrates how to minimize absolute noise while limiting the available SPL. Input Clip: 12 dBu
• Amp Gain: 22 dB
• SNR: 105.5 dB
• Absolute Noise Floor: -71.5 dBu
• SPL is limited to -8.9 dB relative to clip in this minimum absolute noise level example
60,0
40,0
20,0
0,0
-20,0
-40,0
-60,0
-80,0
-100,0
-120,0
-140,0
Analog AES Input Input Mixer
Table 10.4: Analog: Low Noise with Limited Output (Low Input / Low SPL)
Figure 10.5 illustrates how to minimize absolute noise while achieving full power. In this illustration it can be seen
that there is no available headroom.
• Input Clip: 12 dBu
• Amp Gain: 30.9 dB
• SNR: 111.3 dB
• Absolute Noise Floor: -68.4 dBu
80,0
60,0
40,0
20,0
0,0
-20,0
-40,0
-60,0
-80,0
-100,0
-120,0
-140,0
Analog AES Input Input Mixer
Table 10.5: Analog: Low Noise with Full Output Power (Low Input / High SPL)
Module In Module Out Amp Attenuation
Module In Module Out Amp Attenuation
Analog Ref Amp Gain ISVPL Output
Analog Ref Amp Gain ISVPL Output
PLM+ SERIES Operation Manual rev 3.0.1
10. Application Guide
Clip
Nominal
Noise
Clip
Nominal
Noise
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