Amplifiers range in both size and cost. Small battery-powered amplifiers usually provide enough support for a sidewalk musician and are relatively inexpensive. By contrast, professional amplifiers, which may be a necessity for most bands, often are quite large and expensive, costing several thousand dollars. These amplifiers can be heavy and difficult to move, making transportation to and from shows a chore.
The biggest pro of amplifiers is that they amplify the sound. The increased decibels make even the gentlest song sound powerful. A single amplifier easily makes the sound loud enough to play a packed coffee house. Amplifiers are necessary for instruments like the electric guitar, which, without an amplifier would sound quite dinky.
Amplifiers require power, lots of it. Power sources may not be readily available or, even if they are, the amplifiers may cause a short by drawing too much power. Musician who constantly rehearse with amplifiers can expect their electricity bills to increase. Musicians should always check with the venue to make sure that sufficient power is available to power their equipment.
Most amplifiers feature a basic to advanced equalizer. This allows users to tweak the bass, mids and treble at a minimum and customize specific frequencies in advanced setups. The EQ greatly helps to tune the sound coming from the amp and make the music sound more "produced."