MACKIE C300Z
Owner's Manual

PROTECTION
A protection circuit is built into the C300z to protect the high-frequency compression driver from excessive power. When the power to the HF driver approaches the maximum, the power delivered to the driver is momentarily reduced. 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, excessive distortion), you can still damage the speakers in the C300z by overdriving them past their recommended ampli�er power-handling ratings, or past the point of ampli�er clipping. Such damage is beyond the scope of the warranty. stops, and is characterized by a ��at-top� appearance to the waveform when viewed on an oscilloscope.
Normal Sine Wave Signal

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Clipped Sine Wave Signal

Amplifier Power
We give you three power-handling numbers for the C300z: rms (continuous), music, and peak. So how much power do you really need to drive the C300z? 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 ampli�er that is rated at twice the continuous power rating of the loudspeaker (into 8 ohms). For the C300z, this would be 300 watts x 2 = 600 watts per channel into 8 ohms. This insures that the ampli�er can reproduce peaks that are 6 dB higher than the continuous (rms) power-handling rating before clipping occurs.

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 ampli�er whose power rating is below the maximum power-handling rating of the loudspeaker, then they can�t possibly damage the loudspeaker. But if the ampli�er is driven into clipping, even a lower power ampli�er 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 the 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.

RIGGING
The C300z cabinets are �tted with ten rigging points as shown in the diagram on the previous page. These are M10 inserts. M10 threaded eyebolts (M10 x 1.5 mm x 20 mm) are available to �t in these inserts (PA-A1 Eyebolts). WARNING: Never attempt to suspend the C300z loudspeakers by their handles. If you want to suspend them, use the rigging points only. Consult a professional rigger or structural engineer prior to suspending loudspeakers from a structure not intended for that use. Always know the working load limit of the structure supporting the loudspeaker array. Always make sure that the rigging hardware minimum rating is at least �ve times the actual load.
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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 ampli�er) reaches its maximum level. The input signal to the device may continue to increase, but the output simply