When considering to buy a new micro or mini system, you needs to look for various aspects components. Given here is an outline that can help consumers make the right decision.What is a Hi-fi system?These audio units are designed in a manner that they allow individuals to listen to music at different places. There are several components that need to be purchased separately but it can also be bought as a complete packaged system. The three major components of a mini or micro stereo system are as follows:1. Audio source: The audio source could be anything from a CD player, radio device, and cassette player, to auxiliary port, iPod dock and turntable. Majority of systems have two or more of these sources.2. Amplifier: The function of the amplifier is to control the balance and the volume of sound.3. Speakers: Hi-fi systems generally have two speakers for producing stereo sound. With some extremely advanced systems, you will get up to seven speakers, creating the setup of a home theatre.What are the different types of Hi-fi systems?These stereo systems are available in two sizes: Micro and Mini• Hi-Fi Micro systems: These units are small and have a compact size suitable for office spaces or lounge rooms. Most often, they come with an AM/FM tuner, a CD player and an iPod dock in the latest ones. The speakers of a micro system will not be very powerful because their range is between 10 and 30 watts per channel.• Mini systems: These systems are larger and are suitable for bigger houses or public spaces. They come with a multiple-disc CD changer that has the ability to change between three to five CDs at a time. Speakers with this system are extremely powerful and they have a range of 30 to 100 watts per channel. Some mini systems have an unattached subwoofer to amplify bass reproduction.Commonly, Hi-fi Micro systems as well as Mini systems come with speakers. Audio sources will differ depending on the model you choose. The essential components of a system are dependent on your purpose of use and what you want the system to do.Hi-fi systems can playback music from several formats:1. CDs: Almost all systems have an in-built CD player that plays both CD-R and CD-RW format. Many latest systems can playback MP3 as well, making it possible for you to play music from CD’s containing files copied from your computer.2. Radio: Hi-fi systems commonly have an AM/FM tuner. Latest models have a DAB radio tuner making it possible for you to listen to digital radio broadcasts.3. iPod: An iPod docking station is included in some systems. Songs from your iPod can be played through the stereo speakers. You can also charge your iPod by keeping it docked.4. USB drive or MP3 player: Some systems have a USB input. These inputs allow you to connect your MP3 player or iPod for playback. Systems capable of MP3 playback are preferred these days, because they allow you to copy songs to a USB flash drive from your computer and then play them through the stereo system.What more should you look out for?• Output power – 20 watts is optimum for clear sound in a medium-sized room, while 100 watts is required for audible sound across a large house. When you buy a system, check if output mentioned is per channel, or total output.• DVD playback – An in built DVD player is ideal if you want to enjoy quality sound movies, without spending extensively on a home theatre system.• Radio pre-sets – Radio channels can be saved as pre-sets. You can switch from one channel to the other without having to tune the frequency again.