EFFECTS

Sound effects, i.e. the non-musical elements on a soundtrack, other than dialogue.

FOLEY

The art of recreating incidental sound effects, such as footsteps or rustling clothes, synchronized with the moving picture. Named after one of its first practitioners.

HIFI	HiFi is an abbreviation of the word High Fidelity. This term means that a true HiFi system has a natural sound reproduction that reflects reality.

HIGHPASS FILTER (HI-PASS)

With the highpass filter, the sidespeakers’ lower frequencies are chosen. If highpass is set to 90 Hz, the sidespeakers will not reproduce sound below 90 Hz. The sidespeakers are relieved of the heavy workload of reproducing low bass. The highpass filter only works when the subwoofer is connected to the pre-out/man-in on the amplifier.

HOME THEATER

When you watch a movie the sound is a big part of the experience. That's why a lot of time and money are spent on sound when a movie is produced. This is very obvious when you watch a movie in a movie theater. The sound fills the entire auditorium and embraces the audience in a way that a regular TV cannot even come close to. A home theater system gives you the sound the filmmakers had in mind when they made their movie. You have your own small movie theater where you can recreate the magic you would otherwise only experience in a big theater. Before you choose a speaker you should first decide if you are going to have an analog or a digital system, because the number of speakers and their placement is different for each of these systems. The most common is the 5.1 format which consists of 6 separate channels. Since the channel for deep bass does not have a full frequency range, it is called a ".1" channel. The speaker set-up for the 5.1 format consist of three front speakers (where the center speaker is placed above or underneath the image source), two surround speakers and one subwoofer.

IMPEDANCE

Impedance is a measurement of resistance. The speaker's resistance identifies how difficult the speaker is to run. Resistance is measured in ohms. The lower the ohms, the “easier” it is for the amplifier to run the speaker. A speaker's impedance – or electrical resistance as a function of the frequency - is a measure of the electrical load placed on the amplifier by the speaker. The greater the impedance, the smaller the amount of current flowing through the speaker will be. A speaker's normal impedance is 4 or 8 ohms. This means that a speaker with an impedance of 4 ohms needs an amplifier that can deliver more current. The lower impedance, the higher the demand placed on the amplifier.

JUDGING SPEAKERS

Once, some sound engineers decided to apply what was, to say the least, a peculiar standard: namely, if a speaker had a straight frequency response in an echo-free (anechoic) test chamber, then the speaker's frequency curve would also be straight in a room at home. However, it's not that simple – the acoustics in a padded test chamber and those in your living room have nothing in common. If you've never been in an anechoic chamber, then you should know that the acoustics there resemble those of a small closet filled with winter overcoats. In an ordinary room at home, on the other hand, all sorts of sounds are reflected as they bounce off walls, floors, ceilings, furniture, etc. If you put a conventional speaker in a room at home and measure the frequency response, it will be anything but straight. From this, we can learn that the measured frequency curves in the speaker’s specification don’t really say much about how the speaker will sound and perform in your own living room. How a person will experience sound is personal and there are no measurements or specifications that can replace your own ear. Always listen to the speaker before you decide. Keep in mind that most new speakers need to play for a while before they perform at their best. The membranes are moving and, from the beginning, their suspension is stiff. This stiffness is softened the more you play them and this contributes to a faster and more precise movement of the cones.

LFE-OUTPUT

If the amplifier has a separate subwoofer or LFE-output, you connect an RCA-cable to this.

LOWPASS FILTER (LO-PASS)

Most subwoofers have a LowPass filter. This filter lets sound through below a specific frequency and stops the higher frequencies. Set at 100 Hz, the frequencies above 100 Hz are muted and are consequently not heard. A LowPass filter should be as ‘steep’ as possible (12dB - 36 dB). LowPass always works, no matter how the subwoofer is connected to the amplifier.

MAGNETIC SHIELDING

Loudspeakers contain magnets and are therefore shielded to prevent disturbances of the TV screen. However, this is not a 100% guarantee of non-interference with television display.

MIX	The blend of dialogue, music, and effects that make up a film's soundtrack. Also, when used as a verb, the process of assembling and balancing these elements electronically, thereby creating the final soundtrack.

MONO	The term mono identifies recordings and reproduction through one channel.

MP3

MP3 is today's most used standard for digitally compressed music. Its advantage is that you can house a large amount of music on a relatively small hard disk. A portable 20-GB MP3 player like an iPod can store about 5,000 tracks. The 'downside' of MP3 and similar compression formats is that conversion to the format degrades the quality of the recording in the process of compression. When listening through a pair of ear-pod speakers, you probably won't notice the difference, but when you play an MP3 track through a good sound system with good speakers the difference becomes noticeable – particularly in terms of bass losses and a 'narrow' sound picture with less detail. If sound quality is important to you, don't be satisfied with PC sound quality in your sound system.

OPTICAL SOUNDTRACK

A clear photographic strip adjacent to the picture on a 35 mm movie print, varying in a width according to the sound. As the film is pulled through the movie projector's sound head, a narrow light beam passes through the moving soundtrack, causing the intensity of the beam to vary. The varying light fails on a sensor that creates electrical signals for the theater's loudspeakers to convert back to sound.

PASSIVE RADIATOR

A passive radiator is actual nothing more than a bass-reflex port. The technique is used to avoid long bass-reflex pipes. The bass-reflex principle means that the air pipe in the bass-reflex port is made to resonate so that the port generates the bass sound. If there is insufficient air volume in the speaker cabinet, the bass-reflex pipe must be very long if it is to resonate in the right way. That is why a passive radiator is used, and its moving mass matches the air volume in the bass reflex port. When the passive radiator resonates, it provides the right bass pressure. The rest of the bass sound is generated by the active bass element.

PHASE ADJUSTMENT

A function with active subwoofers letting the bass play in phase or out of phase with the side speakers. Correctly set, the bass will be experienced as synchronized.