Quick Links
So you’re new to the whole home theater thing, and you’re not sure what all the terms mean. Well, these are some of the most important concepts you should know, so time to get your learn on.
These terms are in order of what I thought was related, instead of alphabetical.
Channels
This refers to the number of audio channels. Each channel is its own independent audio stream.Stereo audiohas two channels of audio, for example. Mono audio has just one. Stereo is the most common setup in general, but big multichannel systems are at the top of the pile when it comes to immersion and more common for home theater systems. Sometimes you’ll see a decimal point in audio channel numbers, such as “2.1,” which means there are two audio channels, and one dedicated subwoofer speaker.
Surround Sound
Surround sound systems have many channels, typically five or seven, arranged around the listener to create an immersive experience where you can hear where things are coming from with high precision. Of course, the media you’re watching must be mastered for surround sound to take full advantage of a setup like this.
Dolby Atmos
Atmosis a surround sound mastering standard that’s mainly known for adding height channels, which means having speakers on the ceiling (or upward-firing floor speakers that bounds off the ceiling) that let you hear things going overhead, or coming from above. It supports up to 128 audio channels when mastering, depending on the implementation, and can map virtual sound “objects” to specific positions within 3D space using those height channel speakers. Of course, to take full advantage of Atmos, you need some pretty elaborate gear.
DTS
DTSor Digital Theater System is a competitor to Dolby, and there have been various DTS codecs over the years. If you check the back of a DVD or Blu Ray, you’ll usually see which DTS version its mastered for, but as long as your audio system supports DTS you should hear something come out of your speakers. DTS is widely used and supported.
THX Certification
This is a certification from Lucasfilm that means a given piece of gear complies with their strict criteria for audio reproduction. You’ve probably seen the THX logo and booming, sweeping intro sound before. Gear with a THX sticker carries a premium. However, just because something lacks this certification, doesn’t make it worse than THX-certified gear!
Subwoofer
This is the big boom-boom speaker that’s specially designed for low-frequency sound. I like putting mineagainst my movie couch. Some surround sound systems even come withtwo subwoofers.
Soundstage
This is the spatial arrangement of what you perceive when listening to something. For example, in orchestral music, your brain might hear how the different instruments are arranged from the point of view of the microphone.
Frequency Response
This is the range of audio frequencies a speaker can produce measured in Hz (Hertz). Human hearing typically falls between 20Hz and 20KHz. The wider the frequency response range, the more accurate and true the sound reproduction is compared to the original recording. So wider is generally better.
Crossover
A crossover is an electronic device (or a software function) that determines at which frequencies sound should be sent to different speakers. For example, if you have a speaker cabinet with a tweeter, midrange speaker, and subwoofer, the crossover will only send frequencies to each speaker that it’s best suited for. By giving each speaker the optimum range of frequencies, you’ll get better, fuller, and well-separated sound.
Speaker Sensitivity
This is a speaker specification measured in dB (decibels), and is measured one meter away from a speaker receiving one Watt of power. So a sensitivity of 90dB means it produces 90dB of sound pressure using one watt of power from the amplifier. Remember that for every 3dB increase you get double the pressure, since dB is not on a linear scale.
Sensitivity is useful for a number of things, such as figuring out how loud a given speaker can get paired with a specific amp. It’s also useful to ensure that if you’re connecting multiple speakers to one amp, that some aren’t a lot louder at the same amplification levels.
Alteratively, if you have a setup where every speaker isn’t the same distance from you, you can compensate for the loss of volume by using speakers that are more sensitive, and then by the time the sound arrives at your ears, the volume levels are the same as the speakers closer to you. As you can see, this is a pretty useful number!
