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What is...? (A short glossary for newcomers)

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  • What is...? (A short glossary for newcomers)

    Amplifier- A device used to increase the gain of a signal to a listenable level. These come in many varieties. The most common for home theater is a receiver which is an all-in-one solution to be discussed later.

    Analog- A word used to describe a signal or device that operates without using digital components. It could be a solid state amplifier, tube amp, turn table or tape deck. Also could be used to describe a cable, though this can be misleading as there is no discernable difference between an analog or digital RCA cable.

    Bookshelf Speaker- A sometimes deceiving term used to indicate a small speaker. Most nowadays would NOT fit on a standard bookshelf. Generally a two-way design featuring a woofer and a tweeter of various sizes and designs. This is your “basic” speaker.

    Blu-Ray- The winner of the recent “format wars” for high definition next generation DVD style content. Developed by Sony, this format is lauded for its high storage capacity and its ability for copy protection. Like HD-DVD, it presents movies in full HD with enhanced sound capabilities.

    Cathode Ray Tube (CRT)- An analog television using a tube to display a picture. Known for being heavy but also very good looking for most resolutions. Basically phased out of the market but some are still available. They are very heavy and prone to magnetic interference from non-shielded drivers.

    Center Channel- This is a speaker designed for use in the middle of your system, either above or below your screen. It has the hardest job of all home theater speakers and is most of the time the most neglected due to space and WAF concerns. It must reproduce nearly all of the dialogue of a movie and all the sounds that occur in the middle. The best center is one that matches your mains perfectly, but most of the time it is of a different design for space and symmetry considerations.

    Class A-Type of amplifier. To keep things really basic we will say that they sound good but are wholly inefficient devices which means they make a lot of heat.

    Class AB-Another type of amplifier. Not generally regarded for their sound quality these amps can make a lot of power with more efficiency than a class A. Usually used in PA or pro equipment for sound reinforcement. Some modern amps will switch to AB after a certain output point to increase efficiency and power at a sacrifice for quality.

    Class D-This is a digital amplifier which generally uses pulse width modulation (PWM). Known for their efficiency and cool running even in high power scenarios. Some people feel these amps sound too “sterile or cold” in relation to their clean digital sound.

    Clipping-A general term used to describe distortion of a signal. Generally sounds harsh or garbled.

    Component Video-A video cable capable of full HD resolution. This cable carries an analog video signal among 3 cables, a red, green, and blue. These are basically 3 RCA cables put together.

    Composite Video-This is the old school standard video, the Yellow RCA. All information is sent on a single cable which is why the other standards look better.

    Coaxial cable- This is a single cable that can actually take different forms. It may be the simple cable style connector (called F connector) or could be terminated in RCAs. Digital sound cables are called digital coax because they are a single RCA connector design.

    Crossover- A generic term for any device, active or passive, that filters the sound going to your speaker. This can be a high pass (blocks lows), low pass (blocks highs) or band-pass (blocks lows and highs, letting some middle frequencies through). Your most common active crossover is the one built into receivers. These will limit the low frequencies to your main and surround speakers and route the signal to the subwoofer.

    Cube speaker- This is your standard HTIB (home theater in a box) or computer speaker. A small, usually single driver, enclosure with limited frequency response on both the high and low end. Usually compensated by a poorly designed subwoofer to enhance the midbass region, which only results in a boomy and directional sound.

    DAC- Digital to Analog Converter. This device is found in anything that is digital but can send an analog signal. It takes a digital format from an optical or coax cable (generally), converts it to an analog signal and sends it out via RCA cables (generally). Found in DVD players, CD players, PC soundcards, Receivers, HT preamps etc… Also available as a high-end stand alone option mainly for music use.

    Digital output- This can refer to many different cable types available on the market. The most popular for sound are SPDIF (optical) and Digital Coax (coaxial) but there is also a balanced format transmitted on XLR cables called AES/EBU. This is uncommon with consumer level equipment. If video is transmitted digitally it will be done via HDMI or DVI. Note that HDMI can also carry the audio signal.

    Dolby Digital-A sound compression technique used to bring theater quality surround sound to your home. While it is limited in bitrate, it is still more than adequate for most users. This format comes in many flavors- DD, DDplus (HD), DD-EX (6.1), Dolby TrueHD (HD).

    Driver- A generic term for any singular speaker that may make up part of a multi-driver loudspeaker.

    DTS-Digital Theater Sound. A rival to dolby digital that never really caught on for mainstream use. It too is just a compression scheme, but it is capable of higher bitrates and therefore a better over all sound presentation. Usually seen on “special edition” DVDs or high-end movies. This format also comes in many flavors- DTS, DTS-ES (6.1), DTS HD (HD), DTS MasterHD (HD).

    DVD player- The standard for video playback currently. DVD is a small, CD sized disc that can hold an entire movie and sometimes extra content on it. It can be two sided and have double layers. The layer transition is that pause you see in movies, sometimes done artfully, other times horribly and you panic thinking something is wrong for a split second. The player itself is a laser device, just like a CD player, but at a different frequency. Most DVD players today can output 480p over component cable or even upscale to HD resolution. Note that even though the signal is upconverted it is still DVD resolution and will not look that much better. DVDs support 6.1 channel sound in Dolby Digital or DTS format.

    F3-This is the -3dB point of a speaker, or, when the frequency response starts to roll off. This will give you an idea of the kind of response you will get, but realize that rooms tend to change this number…sometimes significantly for better or worse.

    Frequency response- This is the working band of the speaker or other component. Human hearing is considered 20hz-20000hz and as a simple guide you could consider the following general responses:
    Tiny cube 100hz or higher -15,000hz (small 1 driver cube)
    Small bookshelf 80hz -20,000hz (4” driver and tweeter)
    Med-Large bookshelf 55hz-20,000hz (5.25-6.5” driver and tweeter)
    Small tower 45hz-20,000hz (single bass driver and tweeter)
    Mid tower 40hz-20,000hz (any combination)
    Large tower 35hz-20,000hz (any combination)

    Full-range speaker- Kind of a myth in the real world, a full range speaker would produce the full spectrum of sound 20hz-20000hz. In practice this usually involves a very large cabinet that most people simply could not get away with. Luckily, the addition of a subwoofer makes it easy for just about any speaker combination to achieve full-range sound.

    HD (HDTV)- High definition (Television). A generic term for anything that is broadcast at 720p or higher.

    HD-DVD- A next generation DVD format that is now dead. Designed by Toshiba and Microsoft, HD-DVD was the first available format that used new technology discs to display movies in full HD resolution. They also had support for advanced sound codecs which allowed a much fuller presentation and possible 7.1 support.

    HTIB (Home theater in a box)- A generic term for a complete system in one container. Usually consists of 5 cubes, a subwoofer, and a dvd/receiver system. A lot of people start with these and then move on to higher quality components. The kicker is that there are a lot of systems that start not too far over the standard HTIB price and will give the user much more enjoyment.

    HT (Home theater)- A generic term for any room in your house that has a 5.1 or greater surround sound system. Some people have dedicated rooms that feature a “real” theater like experience all the way down to the seating and popcorn makers.

    Headroom-A term used to describe reserve power before an amplifier or signal distorts or clips. Modern rock does not need much due to compression of the signal, but classical music and well-recorded music of other genres really need reserves to create a natural presentation. Amplifiers have to increase 2x in wattage to increase volume by 3dB so if you needed 18dB of headroom with a 5w steady-state amplifier, you would need 320w to achieve this.

    High pass- A crossover slope that attenuates low frequencies. These are seen at the passive level on tweeters and at the active level on receiver crossovers to prevent damage to the main speakers due to low frequency energy.

    Integrated Amplifier- This is an amplifier as described above that also has some form of a preamp stage in it. It will have volume control and possibly multiple inputs and maybe even outputs. These can be multi-channel, but are generally 2 channel due to its intended use as a standalone sound system.
    Regular guy.
    Tubey or not tubey, that is the question :smoke1:

  • #2
    LCD- A type of display using liquid crystal. Popular in use today as HDTVs and computer monitors. Capable of full HD output, but is dependent upon model.

    LCR-A designation some manufacturers use to indicate a speaker may be used as a Left, right or center channel.

    LFE- (Low Frequency Effect). This signal is the .1 in the 5.1 scheme. It is a dedicated bass channel that is automatically routed to the subwoofer. This is not to be confused with the low frequency energy that might also be sent to the sub via system crossover frequency.

    Low Pass- A generic term for a crossover that blocks high frequency energy. On the passive level it is used on the woofer in a 2-way speaker. On the active level it is used to route frequencies to the subwoofer that may be dangerous for your main speakers.

    Midbass-A term used to describe the upper bass frequencies.

    Midrange-A term used to describe the mid-range frequencies normally considered to be the vocal range. In speaker terms it is usually a smaller cone speaker, say 4” average and if used in a 3-way system, would have a band-pass crossover.

    Optical cable- This is the SPDIF cable which stands for Sony-Philips Digital Interface Format. This uses an optical signal to transmit digital sound information. (It’s the one that looks like a red light when on!).

    Plasma TV- Television using plasma as its picture creation source. Popular with larger sized HDTVs. Known for their picture quality and high prices.

    Phono-This is a jack used for a turntable. Many receivers still have a phono-in which means they have a built in preamp. Phono inputs will also have something called RIAA equalization which is a passive EQ that is made to supposedly make all records sound the same universally.

    Phono preamp- A preamp designed strictly for use with a turntable. You will notice it always has a ground screw in addition to the standard RCA connection. This device will contain the RIAA EQ and a preamp to increase the output signal of the turntable.

    Plate amp- An amplifier built onto a plate for use with powered speakers or subwoofers. Generally these amps are high distortion, high power designs because it is hard to hear under 10% distortion through a bass driver. This keeps the amps at a lower cost than an audiophile version would be.

    Preamp (2ch)-This is a high end device that is basically just a source switch. Some preamps are passive which means they are just jacks and switches, while others can be solid state (possibly using op-amps) or tube driven which uses tube plates to create gain.

    Pre/pro (HT)- You can consider this a receiver without an amplifier built in. It handles all your signal switching and digital sound processing.

    Projector (PJ)- A device that projects its image onto a screen from a distance. Modern projectors are either LCD or DLP technologies and are capable of full HD output. CRT projectors are also built, but are pretty much specialty items. They are known for their picture quality, but also their high price, pickiness, and weight. Most people who have a “true home theater” use a projector for the full experience. The downside is short bulb life and high replacement cost.

    RCA- A standard connection device. Usually red and white when dealing with audio. It is a single conductor system that has a center pin that carries signal and a ground wrapped inside the jacket.

    Receiver- A standard home theater and general purpose device. This is an all-in-one for most people. It can receive digital and analog sound and video signals, process them, and output them via an internal amplifier, usually 5 or more channels. A great starting point in the world of home theater and sound reproduction in your home.

    S-video- An upgrade over composite, this cable carries video information on two conductors instead of one. It provides a slight increase in video performance.

    Single driver fullrange- A unique type of speaker that is meant to perform full-range duties without separate drivers or crossovers. These speakers have a unique sound but generally cannot make bass unless put in a large, unsightly horn.

    Speaker- A generic term that can mean a single driver or a full loudspeaker cabinet.

    Subwoofer- A large speaker dedicated to bass below 100hz. Generally 8" or larger but there are several good 6.5" examples now. These speakers are usually powered by a plate amp built into the back of the enclosure. This is the .1 of your 5.1 system.

    Toe-in- A term used to describe angling the speakers in towards the center position. Usually only a few degrees will do you. Toe-in can help with imaging and soundstage and an extreme amount will give you a mono, center channel only type of sound with only the Left-Right speakers operating.

    Toslink-A term for the digital coaxial cable. Developed by Toshiba as a rival for the SPDIF format. They are still both generally used and accepted.

    Tower speaker- A large, lean cabinet (hence the name tower) housing any multitude of drivers. They can be small (midtowers) or large and can be simple 2-way or any combination of complex arrangements.

    Turntable-A record player. Popular still in some groups, known for warm, smooth analog sound. A very costly investment
    Regular guy.
    Tubey or not tubey, that is the question :smoke1:


    • #3
      Besides work. ;)

      I did it all in word then pasted. :goodvibes:
      Regular guy.
      Tubey or not tubey, that is the question :smoke1:


      • #4
        How about some more vague terms?

        laid back


        • #5
          Added toe-in and headroom.

          The others are very subjective. Maybe a paper on speaker characteristics is more in order for those?
          Regular guy.
          Tubey or not tubey, that is the question :smoke1:


          • #6
            good list, Bill.

            How about adding HT-bypass?


            • #7
              What is "reference levels", pertaining to volume? What do people mean when they say they have their volume at -5db? -5 from what?


              • #8
                Originally posted by Jack
                What is "reference levels", pertaining to volume? What do people mean when they say they have their volume at -5db? -5 from what?
                The movie industry has set up various audio standards over the years to try and insure a consistent experience theater to theater, and one of those is the "reference level." Basically it set the max peak level at 105db from the full range channels and 115 db from the subwoofer, measured at the seats.

                In practice, test tones or pink noise on a CD or DVD can be recorded with relation to max and then used to calibrate. Most AV receivers have built in test tones as well for setting up channel levels.

                The way it works with most receivers (it varies unit to unit read the instructions) is you set the master volume to 0.0 and then play a test tone through each channel one at a time. Your receiver should have a channel level setting or trim level setting menu where you can measure the test tone and adjust until it reads properly. The built in test tones in most receivers are at -30db and therefore should measure at 75 db at the seats. Simply play the tone and adjust until you read 75 db on your SPL meter. Move on to the next speaker and repeat. Note that some of the popular setup DVD's have the tones recorded at -20db so you would look for 85db on the meter.

                Once calibrated, if you say you are listening at -6 db, I can listen to the same movie in my calibrated room and have a darn good idea of exactly how loud it was for you.


                • #9
                  Ah, now I see, thanks! I assume when you say set the master volume to 0.0, you mean as high as it goes? Because when I set it to O, the test tones are of course inaudible. I'll have to pick up a SPL meter one of these days, been meaning to get one. I've just been using Audyssey on my Onkyo to set the speaker levels and then fiddling with it manually to get it just where I want it.


                  • #10
                    Your receiver may not be designed for reference calibration then. A typical AV receiver has a master volume scale that measures in negative db over a range that is usually something like -60 to +12 where 0 is generally pretty darn loud.


                    • #11
                      Ah, learned something else new today. Yeah, it's an Onkyo TX-SR505, not exactly top of the line :)


                      • #12
                        I randomly ran across this thread today looking up DAC stuff and thought I'd give it a bump...
                        :bump 1:
                        HT Gear (AVS Link)
                        Rk: MA WR-37-32
                        Pwr: 20A, Surge-X SEQ, M1500-UPS
                        Proj: JVC RS20, 128" 2.4:1 CaradaBW, ISCOIIIL, CineSlide, RadianceXE
                        Cbl: DirectTV C31/700 Genie receiver
                        Rec: 5308CI + XPA-3
                        BR: Oppo BDP-103
                        Gm: 360 Pro
                        LR/C: RS1KSig/RSC200Sig
                        S/R: RSS300/RS250MkII
                        Sub: SVS PB12-Ultra/2
                        Off: HRT MS DAC, USP-1, UPA-2, ERC-1, Ultra10, WAF-1 Ninja+No-Rez
                        Off2: Gizmo, WAF-1
                        TCA: 3x Gizmo 1.0or,5x v1.0M; 5xWAF-1


                        • #13
                          M.I.A. - BillNChristy and Dweekie. :sigh:


                          • #14
                            Originally posted by dvenardos
                            M.I.A. - BillNChristy and Dweekie. :sigh:
                            Really. I know that Bill got his home theater flooded last year and that kind of turned him off of the hobby. Dweekie is around once and a while.