Video and Audio Center Blog



Wednesday, February 4, 2015

CHOOSING AN AMPLIFIER - HISTORY & TIPS



There was a time when the TV ruled the living room, not because of how good the picture was, but more so because it was the only game in town. TVs were tube-based and on average 19" in size and color, well that was an expensive option over black and white. Besides, how many TV shows were in color anyway?

Flash forward 60+ years and 50, 60 and 70-inch TVs now rule. Filled with tech that past TV viewers never dreamed of, one thing is still lacking. Sound. Hence the appearance of the home theater. Savvy TV viewers figured out early on that the audio coming from the TV had limitations. So the TV viewer decided to get full-on speakers and connect them to the TV. This led to multiple speakers able to provide surround sound, rear surround and much more -- thanks to mature technologies like Dolby Digital and emerging technologies like Dolby Atmos.

Arranged around a room, a set of speakers makes what IS a home theater, complimenting the TV's visual might with awesome sound. But to drive the speakers, an amplifier is needed. It too has evolved, becoming the  AV (audio/video) receiver for taking and controlling video so that it can be sent to the TV. AV receivers are impressive to look at; they're usually a jet or matt black with big knobs and multitudes of tabs and buttons controlling a vast array of audio and video features. Even if all you ever use is the remote, the number of choices of sound quality results can seem staggering. Especially if you're less familiar with what makes for good audio. So with that in mind, lets blow away the smoke hiding the basics of what makes for a good AV receiver without having to resort of charts, diagrams or sound theory. It's what you hear that counts.

POWER
An AV receiver gives the amount of power it possesses in watts; for example 150 watts. The more power, the louder the volume can become, but more importantly, the louder it can be before it starts to distort. So a realistic way to look at this might be to say that a 200 watt AV receiver @ 70% volume will sound "cleaner" than a 125 watt receiver turned all the way up. But another thing to keep in mind is RMS --  a number noting the average power output of the speaker over a period of time. For many this is a more accurate way to look at the amount of "oomph" the receiver can turn out to the speakers its in the specifications so all that is needed is to look.

HOW MUCH POWER
An amplifier must supply power to the total number of speakers connected to it evenly. Speakers are rated for their power requirements and so if a speaker with a nominal impedance of 8 ohms is rated at 100 watts, then the amp needs to be rated at about double that -- in this case that would be up to 200 watts per channel. So when getting a receiver for the first time or in tandem with speakers, be sure to check the speakers capabilities in this area first, then make your decision as to the amplifier with this in mind.

HOW MANY SPEAKERS
AV receivers provide for multiple speakers to be attached to them. For a stereo receiver, its just two but for multichannel capable receivers, it can be many (for example, a 5.1 or 7.1 or a 9.2 system in which the 1 or 2 represents a self-powered subwoofer attached). The receiver can have more speaker capability than the speakers in the home theater as you can always add more speakers.


BELLS and WHISTLES
AV receivers offer a wide array of audio modification technologies, from auto calibrating all of the speakers using a microphone to turning off the video circuitry so that the music being played is more pure. Other examples include being able to act as a video switcher and handling 3D video as well as passing through 4K high resolution. More recently Bluetooth has been added and new audio tech such as Dolby Atmos. The main issue here is that this is built into the hardware and so must be present when you get the receiver it cant be updated at a later time.

An AV receiver was once a major investment in terms of cost and commitment, but now they have become more affordable even as the brand names like Denon and Sony and others have maintained their level of excellence for sound reproduction. Pair an AV receiver with a set of speakers and a big TV and your home theater will be a place where many happy hours of listening to music and watching TV and movies will be spent.

1 comment:

  1. These are really best advice, thanks for sharing it . Generally you should pick an amplifier that can deliver power equal to twice the speaker’s program/continuous power rating.


    Andrew@EmergencyAlertingDevicesDeaf

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