SENSITIVITY – SOUND PRESSURE LEVEL - DECIBEL

The sensitivity specifies how easy the loudspeaker is for an amplifier to run. A value of 90 dB says the speaker gives a sound level of 90 dB at 1 Watt signal in. The sound pressure level (SPL) is a measurement of the amplitude of sound and is measured in decibels, abbreviated as dB. The absolute weakest sound a human can hear is just below 0dB, and the upper pain threshold that our ears and brains can tolerate is around 130dB. When the SPL is increased by 10 dB, we experience a doubling of the sound level. A normal conversation has an SPL of around 70 dB, while a jet plane at close quarters has a level of 130 dB or more, which is close to or over our pain threshold.

SOUND STAGE

When you listen to a speaker you should get the feeling that the sound is 3-dimensional. If a speaker delivers a good sound image you should be able, with your eyes closed, to place the location of individual instruments, voices, sound effects, etc., without noticing the location of the speaker itself. The speaker's placement and its ability to spread the sound are very important to a faithful reproduction of the intended sound image.

SPEAKER LEVEL INPUT

If the amplifier is missing a subwoofer output, the loudspeaker cables from the amplifier should be drawn to the speaker level input and then from the speaker level output to the loudspeakers.

SPEAKER WIRE AND BINDING POSTS

Your sound system will never be better than its weakest component. If you have put your money into expensive electronics and speakers, you should also look at your choice of speaker wire. Wire of good quality can make a difference in how your sound system performs. The best wires are made of higher-grade copper, which has a very good conductivity. Wires come in several thicknesses. Choose a thick cable, at least between 12 – 16 AWG (American Wire Gauge), which suits most good quality systems. The speaker wire can be connected between speakers and receivers/amplifiers in different ways. It is best to choose electronics and speakers with heavy-duty nickel- or gold-plated binding posts that accept bare wire, banana plugs or spade lugs. It is also an advantage if there is a good amount of space in the area around the binding posts, allowing you to have ample maneuvering room for your fingers.

STEREO

From the Greek word for solid. Identifies sound recording and reproduction by more than one (mono) channel. In home music reproduction, 'stereo' came to mean two channels (left and right). In the film industry, however, 'stereo' came to mean at least four channels. Besides left and right channels, proper movie stereo - like Dolby cinema and home theater formats - has a center channel to keep dialogue centered on the screen, plus one or more surround channels (see Surround sound).

SUBWOOFER

A loudspeaker specially developed for playing deep bass – frequencies below 100 Hz. your amplifier drives a passive subwoofer. A powered subwoofer has a built-in amplifier.

SUPER AUDIO CD (SACD)

CD discs recorded in the Super Audio format reproduce frequencies far above the range that is audible to humans. However, some people believe that this more complete sound picture delivers a better listening experience. SACD uses a process called 'Direct Stream Digital' (DSD) to achieve a sampling rate of 2.82 MHz – 64 times more than a normal CD disc. SACD discs can only be played on stereo systems that support the Super Audio format.

SURROUND SOUND

The term surround refers to the speaker’s reproduction of ambience, atmospherics, and occasional special effects from any point around the listener by means of multi-channel sound recording and reproduction. The speakers placed in the back of home theater are usually called surround speakers.

THX®

THX is a standard for optimizing the presentation of sound and images in a movie. George Lucas, the man behind the Star Wars movies, is also the man behind the THX standard. In order to qualify for a THX stamp, a product or theater must first be approved by Lucas Film. THX is therefore not a sound system, but rather a quality guarantee.

TWEETER (TREBLE)

The tweeter reproduces the highest notes. The frequency range is usually between 4000 – 20,000 Hz. However there are sound formats that theoretically can reproduce higher frequencies than 20,000 Hz. In spite of this, the human ear can’t hear frequencies much higher than 20,000 Hz.

VOICE-MATCHING

In a home theater it is important that sound from the different speakers sound the same. Voice matching means that the reproduction of voices from the speakers has been matched with each other so they sound the same no matter which speaker they come from. If the voices that ‘wander’ between the speakers across the sound stage (as the actor moves) sound different, the sound will be experienced as unnatural. To guarantee the same tonal quality across the sound stage, drivers and crossovers of the front speakers should be the same. It is preferable, of course, to have exactly the same sidespeakers as front speakers.

WATT OCH EFFECT

One of the most popular terms in the HiFi field is watt. A watt is a unit of measurement describing how much electrical energy per second an amplifier can deliver to a speaker and how much electrical energy per second a speaker can handle. A watt is not a measurement of quality, but rather a measurement of quantity, in other words, the volume of sound. The quality of the amplifier is closely linked to its ability to deliver enough current to the speaker. Current is measured in amperes. A speaker needs current to transform the electrical music signal into music that is pleasing to the ear. The more current the amplifier can deliver to the speaker, the better the music reproduced by the speaker will be. A good amplifier can dynamically deliver between 50 and 100 amperes.

WOOFER

The woofer usually reproduces the midrange and bass notes. The bass frequency range normally lies between 20 – 200 Hz, and the midrange is usually between 200 – 4000 Hz.