What’s better about Powered PA speaker vs. the old school of amplifier separates comes down to convenience and sound quality. Before the affordable active speaker, sound engineers and busy musicians (or their roadies) had to haul around a rack full of heavy amplifiers and all the required cables and speakers - all of which have been replaced with the active speaker!

An active PA speaker is simply a speaker that has all of the power and connections inside the same cabinet as the speaker. This all-in-one design also takes the pressure of those of us who really don't know how to choose the right amp and speaker combonations, which can lead to degraded sound quality at best and blown or damaged gear at worst.

Most active powered speakers now feature sophisticated internal circuitry, including an electronic crossover. Their power amplifiers are optimized to work at their peak with each speaker component as well as tightly coupled to the transducers via servo feedback circuitry. In other words, the transducers can "talk back" to the amps to let them know how best to react for power and performance. This closed system means total, precise control and far better sound. Sophisticated signal processing circuitry  within the cabinet lets you exercise control over a wide range of critical functions that you cannot get from a passive crossover system.

An active crossover network is used to divide the audio into frequency ranges that are more suitable for the drivers that will be used to reproduce them. Bi-amplification is the process of dividing a single audio signal into two frequency ranges, which are then sent to two separate amplifiers that in turn drive separate loudspeakers. Bi-amplification also allows the amplifier(s) to be chosen or designed specifically to match the speakers and enclosures. Bi-amping, tri-amping, and beyond have been used in sound reinforcement systems for years and have become quite common in active studio monitors as well.

A crossover is a device that divides an audio signal into separate frequency ranges to route to different transducers (speakers, tweeters, horns, etc.) in an audio reproduction system. You can accomplish this easilly by running the audio through a set of filters. For example, a 2-way crossover may include a lowpass filter that passes a signal with low frequencies to a woofer and a highpass filter to pass frequencies to the appropriate for the tweeter.

Crossovers can be "passive" or "active" designs. Passive crossovers are typically found inside speaker cabinets along with the speaker components, but can be purchased as external components.  The external crossover devices is often connected to their respective speakers via a single jack, but sometimes each speaker component also has its own jack in case you want to bypass the passive crossover.

Active crossovers are for line level signals, therefore they are placed in the audio chain before the power stage and route each frequency range to its own power amp and its own transducers. This is where we get the terms "bi-amp" and "tri-amp".

There are many different types of filter configurations used in crossovers and each can produce subtly different acoustic results. The biggest variable is how steep the roll-off, or rate of attenuation, is at the cutoff frequency. Common configurations are 12, 18, or 24dB per octave. Each design has its own strengths and weaknesses, but in general steeper roll-offs are considered better in modern applications.

Looking to add some low-end thump to your PA system without having to upgrade all your existing gear? Then you're in the market for a subwoofer. A subwoofer is a speaker that's dedicated to producing the lowest tones in your PA system.

Subwoofers handle reproducing audio signals in the 20-100Hz range - sometimes a bit higher and occasionally a bit lower. A sub is used to reproduce the lowest octave or two, below where many "full-range" speakers can effectively operate. It takes a lot of amplifier power and usually very large speaker to produce those low tones at auditorium or even room volumes. If a sub were incorporated into a full-range speaker, the cabinet would be quite difficult to carry.

When the kick drum goes "tick" instead of "thump," or when nobody is picking up the beat and the dancers are just staring at you waiting for some low end thump to guide their movements, you are in need of a subwoofer.  Going past that, adding subwoofers to handle the low end can also take the pressure of your existing speakers and make them less prone to problems or blowing.

As with full-range speakers, you can get powered and un-powered subwoofers. Powered models are very convenient - just plug in and go. Un-powered models will require a separate power amplifier (with LOTS of power) and even possibly an external crossover.

The basic concept of speaker cables is simple: They're wires that connect the output of your mixer, powered mixer, or power amplifier to the input of your loudspeaker(s). Choosing the right connector type is critical; be sure to refer to your owner's manual for your speakers if you're not sure what type of connector to use. There are a number of factors to take into consideration before actually connecting your speakers. The first determination is whether your connection is "balanced" or "unbalanced."

Balanced
Balanced refers to a "3-legged" type of AC electrical signal having two "legs" independent of ground. One is generally considered positive (+) and the other negative (-) in voltage and current flow with respect to ground. Both carry the signal. There is no "signal" carried in the shield or ground connection. The benefit is that any noise that gets induced into the line will be common to both the positive and negative sides and thus canceled when it arrives at its destination, assuming the destination is balanced. This phenomenon is called "Common Mode Rejection." It happens because the receiving device sees the common noise in the signal as out of phase with itself, and cancels it. Balanced lines are generally best for long cable runs due to their ability to reject induced noises. Cables with XLR and TRS type connectors are designed to transmit balanced audio from one balanced device to another.

Unbalanced
An audio signal requires two wires or conductors to function. In an unbalanced situation, one of those conductors is used to carry both the audio signal and ground (shield). Unbalanced circuits tend to be less expensive to construct, but they are much more susceptible to induced noise problems than their balanced counterparts. This is because any induced noise in one conductor is not canceled by similar noise in the other conductor and may be carried with the signal into connected equipment. In general, unbalanced lines should be kept as short as possible (under 25-30' maximum) to minimize potential noise problems. Two-conductor cables with TS or banana plug connectors are the normal cables for unbalanced audio.

Once you have determined whether your connection is balanced or unbalanced, the issue of speaker connectors can then be addressed. There are five common types of connectors: TRS and XLR for balanced connections then TS, banana plugs, or bare wire for unbalanced connections.