The basics
A home cinema AV amplifier controls which audio and video source is selected – from devices like your Blu-ray player, DVD player, iPod and CD players – and processes these incoming signals so they can be outputted to your TV and speakers.
Amplifiers are also sometimes referred to as an AV receiver and the small difference is that receivers come with a built-in radio tuner which, in some models, may be in HD and include Sirius Satellite Radio and Internet Radio.
The other main use of an AV amplifier in your home cinema system is to amplify your audio into multi-channels and power your speakers. If you buy a home cinema system all-in-one package then your AV amplifier will come as part of that and with the necessary specifications to handle the system. But, if you are buying the components of your home cinema system separately then you need to find a receiver to match your needs.
Which size speaker system you want will dictate which AV amplifier you need to buy. Most amplifiers have the capabilities to handle the more basic 3.1 and 5.1 speaker systems but, if you want a bigger system than this, then you will have to find an amplifier that can handle more speakers. Some receivers can handle systems with as much as 11.2 channel operation – which means it can provide audio to eleven speakers and two sub-woofers – for the ultimate surround sound experience. This is one of the main considerations when buying your home cinema AV amplifier and sometimes it is a good idea to purchase an amplifier that can handle a bigger multi-channel operation to what you currently have. This means you have the option to add-on speakers in the future if you wish.
Connections
Another important feature of your AV amplifier is the number of connectors it can provide and you will need to find a device that can handle all the parts of your home cinema system. It is also handy to choose a device with a few extra connections so you have the option to add to your system in the future.
HDMI
With most devices offering high definition images and audio it is essential to buy a receiver with a few HDMI inputs. Most home cinema systems are now geared towards HD and, even if you don’t currently have any HD devices, then it is still worth buying a receiver with HDMI inputs so you have the option in the future. Most receivers come with at least three HDMI inputs and some offer up to six. If you own a 3D TV and 3D Blu-ray player, or think you may invest in one in the future, then you need to make sure the AV amplifier has HDMI v1.4 inputs – which can handle 3D signals. HDMI v1.3 will be fine to handle all your HD signals, though.
Digital audio
Audio can be sent via HDMI but it still may be handy to have a few digital audio inputs. This will let you connect up your CD player and digital TV boxes so you can enjoy the sound through your speaker system.
Analogue video
Again, HDMI is taking over the video input and output, but if these connections are handy if you want to connect your DVD player into your home cinema system. Some receivers can convert this signal and output it to your TV through a HDMI cable which saves having to change the input channel on your TV, too.
Audio
The AV amplifier power rating tells you how much amplification your model can provide for each channel in the system. So if you have a 5.1 multi-channel speaker system, each of the five speakers will be amplified by the specific amount of watts, with a low-frequency output is sent to the sub-woofer. However, more power is not necessarily synonymous with better; it is more about finding the right amount to suit you and your living requirements. If your surround sound system is set-up in a smallish room for instance, then you don’t need a huge power rating. A decent sized 50-100 watt system will be more than enough to fill the room with good quality sound.
But, on the other hand, if you have a big room to fill you might need an output power of more than 150 watts to fill the place. You need to make sure the speakers are compatible with your amplifier and that they can handle the power it will supply, though. As a guide you should choose speakers with half the power rating and same resistance as your AV amplifier to get the results you are after.
With the introduction of Blu-ray a whole range of new audio formats have been introduced that offer HD sound to match the HD images. These formats include Dolby True HD, Dolby Digital Plus and DTS which offer better sound quality than the audio formats on DVDs such as Dolby Digital. The majority of AV receivers can now handle these new audio formats but not every system can – especially budget devices – so before buying it is definitely worth checking the capabilities of your AV receiver first.
Extras features
Connect up your iPod
If you have a stereo amplifier then this is a great addition that lets you enjoy your iPod music through your surround sound speaker system. Stereo amplifiers can connect to your iPod with a cable but the best models have a built-in docking station that you can plug your iPod into. When your iPod is connected some amplifiers also let you control the iPod through the amplifier’s remote control or menu buttons.
Multi-room audio
Some AV amplifiers can let you listen to a CD in one room while somebody is watching a DVD – with different audio – in the main living room. Both devices are controlled by the receiver and this is great if you want music in a different room in the house without having the space to set-up a CD player or radio unit.
Networking
Some amplifiers can connect up to your internet router – via an Ethernet cable or over Wi-Fi – and this lets you stream files from your PC. It means you don’t have to bother transferring data to a USB stick to listen to songs and watch videos on the better quality your home cinema system offers. Different models offer different capabilities – some can play internet radio too.
As with most purchases of this type, the range of choices can be slightly daunting. Take into account the points covered above to help you narrow down your options. It is also worth spending some time reading up on AV amplifier reviews, both online and in specialist magazines to see what other users say before making your final decision.