Sound Output

Sound Blaster 7.1 PCI Express Sound card

How is sound created & outputted?

Sound can be created and outputted through various different ways and has been the longest serving type of media to be outputted through a device with the creation of the radio. Sound can be outputted out of any device is normally linked closely with video, with video & sound being captured seamlessly together and then outputted through various means. Computers, gaming systems & various other devices all make use of sound through different ways which I shall be looking at in the next section, breaking down each type of sound output & technology and look closely and what it does and how it can be used.

Types of sound:

This is the sound output and devices I shall be looking at;

• Sound Cards
• Audio Processor
• Mono Output
• Stereo Output
• 3D Sound Output
• Surround Sound
• Channels
• Sampling Rate
• Memory
• Media Communications Processor
  

Sound Cards:

Sound cards are a widely used hardware to boost audio for systems such as computers which lack in audio processing. Computers today normally provide audio output which is built into motherboards allowing the user to connect devices through a jack lead and have sound output, however this type of audio quality is limited to the type of motherboard being used. For example, gaming motherboards have 7.1 audio systems built into the motherboard with the ability to output surround sound, however older motherboards only provide 2.1 audio output meaning that surround sound is not possible. Due to this the expansion of a sound card is normally used to get better audio quality & surround sound.

Depending on the type of card which has been put into the system depends on the quality which will be outputted, if a old more low spec card is used, the quality in sound isn't going to be great compared to a £100 sound blaster card which is used in audio defining hardware for Dj's & producers as the quality is far more advanced. 

Audio Processor:

Audio processing is used to ensure that analogue and digital sound outputs are correctly outputted when transmitted. The audio processing takes place just before the signal has been transmitted and ensure that the quality of the audio is correct making adjustments to the audio data before it is outputted, audio processing also ensures that over-modulation doesn't occur meaning that the sound quality will be disrupted a lot. It also ensures that the level of noise is reduced to a manageable amount allowing the loudness to be corrected & reduced when necessary. 

They're many methods in ways audio can be processed & modified:
All of these effects can be applied to a audio transmission to change how they are outputted.

• Echo
• Flanger
• Phaser
• Chorus
• Equalization
• Filtering
• Overdrive
• Pitch Shift
• Time Stretching
• Resonators
• Robot voice
• Synthesizer
• Modulation
• Compression
• 3D effects
• Reverse echo

Mono Output:

Mono output is where there is only one channel of output, so this would be used with such things as a headset or speaker where all sound is channeled through and outputted through one single channel. In terms with gaming this would be used with the Xbox Live Headsets & Bluetooth devices where only a single channel is needed for the sound to be outputted through the headset speaker. This is due to all the audio of other people speaking through their headsets being outputted through the single channel.

Stereo Output:

Stereo allows for more than one channel to be outputted through a device, this would be used with such speaker configurations like 2.1, 5.1 or 7.1 where more than one output device is used & different sound is filtered through different channels to provide surround sound or left-channel/right-channel configurations. These are also used in more powerful, headsets & headphones where they can channel alternative sounds through different outputs.

3D Sound Output:

With the advancements made in sound technologies and graphical advancements in gaming, they have created the option of 3D sound output to create a more complex and enjoyable gaming experience as more people are upgrading to home cinema systems they can provide a 3D sound system quite easily to work with their games. 3D sound has been a used technology mostly in cinemas & more advanced systems which require good audio quality. 3D can give the impression of real life sound quality coming through the speakers.

Surround Sound Output:

This works in a very similar way to how 3D works however it doesn't give the same impression of real life audio, although it does give a more advanced sound quality. This is due to sound being outputted through 5 different speakers which are situated around the person, this allows for background sounds to be played in the back speakers and more foreground audio to be played in the front 3. This is commonly used in more advanced audio set ups like home cinemas and PC speaker's such as the Logitech z 5500 7.1 surround sound setup.

Channels:

To output sound channels are used to control where certain elements of audio will be outputted from and allow for a more advanced speaker setup to be made. Channels allow for surround sound and 3D audio configurations to be created & work through these 7 channels; 

0	1	Front left	White
1	2	Front right	Red
2	0	Center	Green
3	5	Low frequency	Purple
4	3	Surround left	Blue
5	4	Surround right	Grey
6	6	Surround back left	Brown
7	7	Surround back right	Khaki

These are the sound channels in which are used in sound cards & sub woofers for large speaker configurations.

Sampling Rate:

This where when sound and audio is recorded and collected, the sampling rate looks at how many samples it can take per unit of time such as a Millisecond, where the more samples are taken the higher the quality of the audio. Throughout time more sample rates have been created and designed to get a better audio quality to output through modern day speaker configurations. 

Here is a breakdown of the sampling rates which are used;

8,000 Hz - Telephone & Encrypted Walkie-Talkies along with wireless communications
11,025 Hz - Quality sampling rate for audio CD's
16,000 Hz - Used in VOIP (Voice over internet protocol)
22,025 Hz - Used for low frequency audio quality
32,000 Hz - Used for digital video recorders & mini DVD recorders
44,100 Hz - Most commonly used for audio formats
48,000 Hz - Most worldwide used sampling rate with most audio frequencies based around the sampling rate
88,200 Hz - Used in professional recording and high-end audio quality