We will have this info in the english manuals, but I would give the info now to our customers. Some already know this way.
You know that SD amps have a clipping indicator LED. It will flash on the exact moment that the output signal reaches the voltage of the power supply.
Example:
On the pic below the power supply voltage is indicated by the horizontal traces and the sine wave is being reproduced at the output of the amp at full amplitude. The clipping LED will flash when the peak voltage of the output signal is equal to the power supply voltage. Any further increase on the volume will make the wave become clipped.
Our testing indicated a 10% clipping maximum is still good for the score. Some systems (with higher power handling capabilities) will handle more, gaining but not much.
(images belongs to startproducingmusic.com)
Ok, now you know what I´m talking about, so lets do the correct adjusting:
SPL competitors
Equipment needed: voltmeter, sine wave disc
1- Put a sine wave disc, you can record sine tracks of any duration using the free program AUDACITY.
2- Disconnect the speaker wires from the amp and set it volume (gain) at minimum. Put the voltmeter (set to volts AC) leads on the output of the amp.
3- Set the HU for 70% of its maximum (or another level, if you know where the HU will distort) All bass gains should be 0.
4- Play the track, slightly set the amplifier (always checking the voltage) knob level (gain) to the position where the yellow LED will indicate clipping. Small changes to the knob can make big changes the voltage on output.
5- SHUT DOWN
6- Reconnect the speakers cables and be happy.
Normal use:
Keep an eye on the clipping LED, fast flashing is OK, too much is not OK.
INFO:
A: There is no danger on the procedure because the amplifiers have PWM power supply, that will limit the voltage without any load on output thus avoiding damaging the output devices (over voltage).
B: When you set to clip at a certain volume without load, when you apply the load the power supply of the amp will have a small voltage drop making the wave clip a little bit, this procedure will set the amp to its max SPL. Further setting may be required because systems will differ.
posted
Very informative Murilo. Nice to see you teaching school here
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