Voltage fluctuations are a problem for any home theater setup, as large power amplifiers found in subwoofers, projectors, RPTV's, and multi-channel power amplifiers tend to create voltage fluctuations in your home's AC power. These low voltage fluctuations can be rather large, reducing your home's wall voltage from a nominal of 117 volts to as low as 100 volts when a loud passage of music, movie soundtrack, or bright and colorful picture via a projector is encountered. A drop of voltage of this magnitude means a dimmer picture for a projector, or a significant loss of power for an amplifier. For example, a 200 watt per channel amplifier will be able to output only 160 watts under these conditions. Further, line voltages in your home fluctuate sometimes as much as 5 volts depending on the time of day.
Higher fluctuations can cause excessive heat and occasionally damage.
In conclusion Power conditioners have come a long way in the last few years. It is clear that if protection for your equipment is the primary focus, then there are a number of excellent choices on the market today. If, however, you are also interested in picture quality and sound quality in your audio video system, then you should consider a more technologically advanced method of power conditioning if you would like to have all that is possible from your home theater investment.