Digital Audio Glossary

ADC - Stands for analog digital converter. A anolog singals into digital signals. Normally information is transmitted, by modulating a transmition. This information describes any system.

Analog converter's can turn signals from analog to digital even before transmitting over communication things and lines. For example a modem turns signals from digital to analog. Other things such as telephone lines, they only carry analog signals.



Alias frequency. These are used in a lot in studios. Without these you could have any type of vocals or live instruments on sings. They are used to change the analogue waveform such as microphone recordings.  The analogue conversion involves quantization , it introduces a small amount of errors. When Computers take samples of the wave form fromn the audio it calculates the amount of depth to take. The higher the bit the more information/quality it would have - this means that the quality of the sound will sound even more better with higher bit. You would be able to hear little things that have a low volume to it... little things such as instruments, you will be able to hear every instrument.

 When it has a low bit, which is 16 bit... it would have less information/quality of the sound. The bit wouldn't capture every sound there is and you wouldn't be able to hear everything to the full extent.
Aliasing is also to do with samples as well. These refers to a effect that causes different signals and it makes sound distorted when sampled.
An example of Alias:             Anti - Alised                                          Alised

Aliasing takes off the quality more and makes it distorted... and smaller. Aliasing = less quality.

 

Binary - This means two, as in two parts. In music terns it has a 1 way how bit resolution is read. When computer takes smaples... the waveform in the audio mesures how much to by the amount of depth.If you have a higher bit, the depth would also be higher which means more wuality. but If you have a less bit, that means less depth which also means less quality. Examples of higher bits is when you buy music from itunes, CD's Etc but when you download things off Youtube it has a less resoultion because the bit is more less as it is a Mp3. However Itunes is Mp3 but it has the same quality and information as a CD information would do than a Youtube one. When downloading a Track from Youtube, it also compress the track as well, this means that it is less clear and you wouldn't be able to listen to the full quality.

This is an exmaple of how Analog data/digital data is captured on to a CD. It has numbers from 0 to 1.

 

Bit depth - is like the quantity that estimates the signal. More bit depth the more accurate many sounds will cone out... But the less depth you have the less quality your sound will come out.
The bit depth determine the dynamic range of recording
The dynamic range increased BG 6, dB for extra bit used
A 16bit word length theoretically gives 96dB of dynamic range
A 24bit word length gives 144 dB.

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 The Clipping - Clipping is when audio signals or wave forms is pushed. This mostly happens when the amplitude is over the limit. Clipping is like amplitude is all about the level. In Logic If the volume goes over the limit that means it is peaking, (It goes red in the dBFS meter bar) and it sounds really loud, with a lot of distortion, it makes a crush sounds. Sometimes it depends on what instrument it's peaking at, for example if you have a bass and it's peaking then it would sound really distorted. If you have a electric guitar and it's peaking then it would definitely sound distorted. Many producer's have to fight and make sure that their sound doesn't peak and sound distorted.

DAC - This stands for Digital to analog converter. This converts digital code to an analog signal, it is the opposite of a ADC (Analog Digital Converter). Siganls are transmitted in Digital form instead of Anlog DAC sends digital informtation in music player's and it coverts digital video signals to analog in televisions and mobile phones... to show colours and the picture. They work like a electronic processor inside Media things and digital audio information.

 

dBFS - The digital level measurement unit is dBFS (Decibel full scale)
0 = number of bits. 'dBFS measures the decibel amplitudes levels in Digtal system'. A digital signal that don't have 0 dBFS can still clip because of the signal reconstruction, it can make the meter bar clip and turn into red. On Logic you will see that it has numbers next to the volume bars, this shows what number of dBFS it is at. It's over the limit the dBFS would have a high number which would probably be (6,0), if it goes over (0,0) that means it''s clipping. If it has a minus (-4,7) this means that it won't go over the limit, distort or clip. It wouldn't show that it has a red bar.

 

Digital audio interface - This allows equipment such as audio mixers recording devices and other things to intercvonnected without taking away any signal quality. It can takes of audio and turn them into digital. when you are encoding a audio signal in digital... sound goes through the ADC and it's used to econde it as a Digital signal.

 

Digital effects processor- A effect processor is like a electronical device that changes singal to add special effects. It's commonly used for guitars, and it acts as preamp device which sends signals to the guitar amplifier. This can be used for live performances or to be used for your track if you're recording. It can contain a lot of effects, things like:
Reverb - This makes the instrument/vocaller sound like he is being played in a hall, it's like a echo effect except it slowly decays, so it makes sound obvious that it doesn't have an echo.
Distortion - This changest the quality of the sound, to make it sound like it has that crunch sound. It takes away a bit of quality as well.

Dither - What dither does is that it makes the all of the little things to the highest quality, it adds sound to the sound signal. The only time you add dither is when you have a 16 bit track. You only add this when you are puttin, your music on a CD. When your track is 24 bit, you do not need to add the dither, this is because at 24 bit the quality would be really good, and for 24bit you do not add this to your CD only if you're putting your track on your phone or USB.

 

Digital mixing console - A mixing console is a electronic device for, routing, combing and changing the dynamics of a digital audio sample. A mixing console controls the out puts in a professional studio, it works like a romote for softwares... Softwars like Logic pro 9. It controls the volumes, the microphones and other things. They are mainly used either in recording studios, broadcasting, television, film productions, public address or a sound reinforcement system.

 

Sample rate - This defines the number of samples per unit. Sample rates must observe the Nyquist Theorem. This theorem states that the sample rate needs to be at least twice the frequency of the highest audio frequencies to be digitised, in order to eradicate distortion. Number of sample taken every second = sampling frqeuncy or sample rate (Hz or kHz). Time = 1 second sample rate = 5Hz.

Examples:
- Telephone, walkie-talkies = 8,000 Hz
- Audio CDs for lower quality = 11,025 Hz
- Camecorder, video tapes ETC = 32,000 Hz
- Audio CD (MPEG-1), Mp3  = 44,100Hz