Loudspeakers

Protection

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

Series

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.

S500

 

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.

 

 

Amplifier Power

 

 

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.

 

 

 

 

 

 

 

 

 

8

S500 Series Loudspeakers

 

 

 

 

 

 

 

 

Recommended Power Ratings

•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)

Preventing Loudspeaker Damage

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.

Normal Sine Wave Signal

Clipped Sine Wave Signal

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.