Audio Systems
Frequently Asked Questions
What is an audio channel?
An audio channel is a signal path of audio information.
When a piece of audio is recorded the producer/sound engineer may combine information from complimentary instruments or microphone positions to make any one channel.
This audio will then be used in playback by being directed to the appropriate playback channel.
What is multi-channel surround sound?
Surround sound describes the playback of audio information that uses multiple audio channels to the front, sides and/or rear of the listener.
Surround sound is perhaps best known from use in cinemas where audiences are enveloped in an audio experience to compliment the visual performance.
The commonest form of multi-channel playback is 5.1 channel – the five channels are centre, front right, front left, rear right surround, rear left surround. The .1 is the subwoofer for low frequency audio.
What is 5.1 and 7.1 channel playback?
5.1 or 7.1 Channel playback systems are multi-channel audio systems that deliver the audio through either 5 or 7 channels.
What does the .1 mean in 7.1 or 5.1 playback?
The .1 refers to sounds that are in the frequency range less than 100Hz. These are commonly referred to as the Low Frequency Effects (LFE) and are reproduced by the subwoofer, hence the .1 has come to be used to describe the subwoofer in an audio system.
What is LOGIC7?
Harman Kardon LOGIC7 is an audio processing technology/system that allows any audio source to be played back in 7.1 channels — putting stereo music tracks into surround sound.
The use of seven channels (rather than the traditional five for multi channel playback) allows the creation of a larger audio sweet spot.
The total systems approach taken by Harman Kardon means that all elements of a LOGIC7 system — the amplifier, the speaker technologies and the system integration into the vehicle — work in harmony. Each system is specifically designed for the vehicle it is fitted to.
What is the benefit of having a higher number of speakers?
Each of the speakers in a sound system is working at an exceptionally high speed to recreate the required sounds. Having a greater number and range of speakers allows them to be more specialised in the frequency range that they cover. The speakers are also able to respond more quickly to the audio information they should be creating as they are not trying to do several jobs simultaneously.
Is there a benefit of having more than one speaker per channel?
Any one channel of audio information can have several speakers working in harmony to deliver the audio information for that channel. Each speaker will be able to focus on a different frequency range of the audio performance and so will be able to deliver that information more accurately to the listener.
Amplifiers are sometimes described as having more channels than the total system has, why is this?
The channels used in describing the overall system are the total number of channels used in playback e.g. LOGIC7 is described as 7.1 channel playback.
The channels used in describing the amplifier are a measure of how many speakers (individually or in pairs) the amplifier is controlling separately — i.e. an 11 channel amp could be using 5 channels to control individual speakers, 4 channels controlling pairs of speakers and 2 channels dedicated to the subwoofer control.
What is discrete playback?
Discrete playback describes a method of playback of multi-channel source material. 5.1 discrete channel media such as DTS & Dolby Digital are the most popular forms of multi-channel Movies and Music today. This media contains at least 6 independent audio channels and requires at least six defined channel locations for optimal playback.
What is DSP (Digital Signal Processing)?
DSP is a means of handling audio information while it is in digital form. It allows the transfer of the information with minimal loss of detail and allows a vast number of calculations to be made in real time to ensure playback purity.
What are MMX (metal matrix) speakers?
Harman Kardon’s patented metal matrix speaker cones are manufactured by anodising both sides of an aluminium core to a precisely controlled thickness. This gives a strong, but lightweight, speaker cone that minimises distortion and delivers crisp performance.
Harman’s metal matrix speakers were originally developed for high end audiophile systems for the home.
What is a “Racetrack subwoofer”?
A key part of a quality audio system is its ability to recreate the low frequency effects from a passage of music or film. This requires a large speaker with the ability to control the movement of large volumes of air — a subwoofer.
When the audio system is one fitted within a car, the space available to be dedicated to a subwoofer is at a premium — a racetrack subwoofer has an elliptical shape which helps to maximise the use of the available space.
What is the audio sweetspot?
The audio sweetspot is where all of the audio information, stereo or multi-channel, is received by the ears at exactly the right time to deliver the prime listening position.
