Mackie S500 Benutzerhandbuch

S500 Series Loudspe

ak

ers

A protection circuit is built into the S512, S515 

and S525 to protect their high-frequency drivers from
excessive power. When tripped, the protection circuit 
substantially reduces the power to the HF driver. After
the driver cools to a safe operating temperature, the 
protection circuit resets and normal operation resumes. 
However, if the protection circuit senses excessive power, 
it will trip again. In this case, it is necessary to reduce
the power to the loudspeaker by either turning down the 
gain controls on the power amplifier or turning down 
the master volume control on the mixer or other sound 
source.
 

CAUTION: The protection circuit is designed 
to protect the HF driver under reasonable
and sensible conditions. Should you choose 

to ignore the warning signs (i.e., frequent clip LED
indications on the mixer or power amplifier, excessive 
distortion), you can still damage the drivers in the S500 
Series loudspeakers by overdriving them past their 
recommended amplifier power-handling ratings, or past 
the point of amplifier clipping. Such damage is beyond the 
scope of the warranty.

The S500 Series loudspeakers have three power-

handling numbers: continuous, program and peak. 
So how much power do you really need to drive these 
loudspeakers? The answer to that question depends on
what type of program material you are running through 
the system and how loud it needs to be. 

Some audio signals have lots of momentary peaks 

whose amplitudes extend far above the average overall 
level of the program. Percussion instruments are a 
good example of this. Other types of signals, like highly 
compressed rock music, have a higher average signal 
level with fewer peaks. Speech reinforcement requires
less power overall, but involves large moment-to-
moment variations in level.

Assuming you want to use the full capability of the 

loudspeaker, and the program contains at least some 
momentary peaks, we recommend that you use an 
amplifier that is rated at twice the continuous power 
rating of the loudspeaker (into 8 ohms). For the S512
loudspeakers, this would be 250 watts x 2 = 500 watts 
per channel into 8 ohms. This ensures that the amplifier
can reproduce peaks that are 6 dB higher than the 
continuous (rms) power-handling rating before clipping 
occurs.

•  S512: 500 watts into 8 ohms (250 watts rms x 2)
•  S515: 600 watts into 8 ohms (300 watts rms x 2)
•  S525: 1200 watts into 8 ohms (600 watts rms x 2)
•  S518S: 900 watts into 8 ohms (450 watts rms x 2)

Speaking of clipping, this is likely the number one 

cause of damage to loudspeakers. Clipping occurs when 
the signal at the output of any device in the system 
(not just the amplifier) reaches its maximum level. The 
input signal to the device may continue to increase, but 
the output simply stops, and is characterized by a “flat-
top” appearance to the waveform.

Clipping interrupts the motion of the transducer, 

creating distortion and excessive heat in the driver, 
which can damage it over time.

Some folks think that if they use a power amplifier 

whose power rating is below the maximum power-
handling rating of the loudspeaker, then they can’t 
possibly damage the loudspeaker. But if the amplifier is 
driven into clipping, even a lower power amplifier can 
damage the loudspeaker.

The bottom line is that to prevent damage to the 

loudspeakers, you must have a properly operating sound 
system. Proper operation of a sound system includes 
being aware of types of audio signals being reproduced, 
controlling the output levels accordingly, and operating 
all the devices in the system so that no clipping occurs 
within the signal chain.

Normal Sine Wave Signal 



Clipped Sine Wave Signal 

