Powere speakers (or active speakers) are speakers that have built-in amplifiers. They can be connected directly to a mixing console or sound source, without the need for an amplifier. Such speakers are available with passive or active crossovers built into them. Powered speakers avoid the necessity of speaker to amplifier matching and limiting is built in. Another advantage of powered speakers is a reduction in the length of cable between amplifier output and speaker driver (some claim this affects maximum slew rate, the rate of change in audio signals) since cable length is very small in powered speakers. Powered speakers ease set-up issues for an audio system, at least to some extent. However since low-level signal cables have to be run to the speakers from a signal source, noise pick-up can be a problem. This can be reduced (even effectively solved) by incorporating "balanced" line inputs into the speakers. When driven by balanced signals (and cables) from the sound source, noise can be greatly reduced. Some powered speaker manufacturers, notably DB Technologies and Phonic, are now incorporating UHF wireless receivers so the speaker requires only a power lead.