Complex sentence: Another advantage of powered speakers is a reduction in the length of cable between the amplifier output and the speaker driver (some claim this affects maximum slew rate, the rate of change in audio signals) since cable length is very short in powered speakers.
Split into simpler sentences: Another advantage of powered speakers is a reduction in the length of cable between the amplifier output and the speaker driver. Some have also described this as affecting the maximum slew rate, the rate of change in audio signals since cable length is very short in powered speakers.