Studer A1 - A3: SPL and EQ Fine-Adjustment; A3: Distortion Check

A Series Active Monitor Speakers
E4/22 Service Date printed: 29.02.00
4.4.2.5 A3: SPL and EQ Fine-Adjustment
• Set balanced generator to 255 mVRMS (i.e. –11.8 dBV or –9.7 dBu);
• Plot frequency response sweep @ 1 m: tolerance according to the graph
below;
• EQ fine-adjustment possibilities:
1. Overall tweeter level (2.2…20 kHz) with trimmer potentiometer RT300
2. Tweeter level @ 6.0 kHz with trimmer potentiometer RT1
3. Tweeter level @ 9.0 kHz with trimmer potentiometer RT2
4. Tweeter level @ 12.5 kHz with trimmer potentiometer RT3
5. Tweeter level @ 20.0 kHz with trimmer potentiometer RT4.
Note: Basic setting of RT1 through RT4: refer to section 4.4.1.5.
4.4.2.6 A3: Distortion Check
• Set balanced generator to 255 mVRMS (i.e. –11.8 dBV or –9.7 dBu);
• Plot a 20 Hz…20 kHz THD sweep @ 1 m: < 1.2% (48 Hz…20 kHz).
SPL @ 1 m
20 50 100 200 500 1 k 2 k 5 k 10 k 20 k
+10
0
–10
–20
–30
[dB]
[Hz]
–10 dB Roll off
THD + N
20 50 100 200 500 1 k 2 k 5 k 10 k 20 k
10
2
1
0.2
0.1
[%]
0.5
5
[Hz]