1. Sound Theory: The origin, propagation and reception of sound – Wave nature of sound –
Reflections, defraction - Amplitude –frequency and phase – Simple and complex waves - Octave,
harmonics, tones and semi tones – Musical sounds and noise – White Noise and Pink Noise -
Human ear – Psychoacoustics and Psycho Acoustical effects - Perception of loudness, pitch and
direction – Ear training
2. Introduction to Studio equipments: Various stages of production: Recording – editing - mixing
and mastering – Studio equipments: Microphones – Consoles – Recorders – Reference Studio
Monitors – Audio interfaces – Effects processors – Audio cables, interconnects and patchbays
3. Audio Measurements: Logarithms – Linear and logarithmic scale of frequency – Decibels -
Decibels for measuring signals – Different types of audio meters – Decibels for measuring
acoustic properties – Weighing networks – Noise flow: Nominal level, Peak level, Signal to Noise
ratio, Headroom and dynamic range – Frequency response, THD – Transient response
4. Microphones: Dynamic microphones – Principles of operation – Condenser microphones –
Electret condenser microphones and ribbon microphones – Microphone sensitivity and polar
patterns – Mic pre-amplifiers – Phantom power – Microphone techniques : Close micing –
Ambient micing – Accented micing – Stereo micing techniques: AB – XY – ORTF – MS – Glumline
– Microphone Accessories: Mic Stands, shockmounts, windshields, pop filters
5. Effects and Signal Processors: Dynamic processors: Compressors – expanders – limiters and
gates – Effects Processors: Reverberation units – delay – phasers and flangers
6. Principles of Digital Recording: Continuous time signals and discrete time signals – Binary
numbers - Sampling – Nyquist Theorem – Quantisation – PCM – Analog to digital converters and
Digital to Analog converters – Word clock – Audio cds – Digital tape recording systems – DVDs
and Bluerays
7. Amplifiers and Speakers: Different types of drivers and specifications – Loud speaker cabinets –
Infinite baffle and vented speakers – Two way and three way configurations – Cross over
networks – Active speakers – Different types of amplifiers – Power rating and impedence
matching –Modes of operation: Stereo, parallel and bridge
8. Surround sound technology: Dolby surround prologic – Dolby digital – DTS – DTS HD Master –
Dolby True HD – Theatre sound – Specifications – A chain and B chain
9. Broadcasting Technology: AM and FM – Television sound – Surround sound for television –
Audio quality
10. Acoustics: Sound isolation and treatment – Effect of boundaries – Standing waves –
Reverberation time – Room dimensions
11. Audio file formats: Compressed and uncompressed audio – Examples and applications
12. Audio for automobile
Understanding the design-layout-specification-power requirements-system, speaker
integration and configuration-measuring method.
REF:
http://documentation.apple.com/en/logicexpress/effects/index.html#chapter=4%26section=1%26tasks=true
http://www.doctorproaudio.com/doctor/temas_en.htm
http://www.presonus.com/community/learn/dynamics-processing-terms-and-tips
http://www.rane.com/note155.html
http://makingmusicmag.com/difference-between-phase-flanger-and-chorus-effect/
http://www.uaudio.com/blog/flangers-and-phasers/
http://docs.otslabs.com/OtsAV/help/index.htm#references/understanding_dynamics_processing.htm
http://www.recordinginstitute.com/da154/ARP/chap3Sig/asp2.html
http://www.jiscdigitalmedia.ac.uk/guide/audio-processing-dynamics-and-compression
http://www.dummies.com/how-to/content/dynamic-processors-compressorslimiters.html
http://www.geofex.com/article_folders/phasers/phase.html
http://www.soundonsound.com/sos/mar06/articles/qa0306_1.htm
http://www.doctorproaudio.com/doctor/temas/dynamics-processors-compressors_en.shtml
http://www.nch.com.au/wavepad/index.html
http://www.avid.com/Trial/ProTools
http://www.stereotool.com/download/
http://www.hongkiat.com/blog/25-free-digital-audio-editors/
white,pink,brown noise
http://www.troycarter.com/the-difference-between-white-noise-and-pink-noise-by-troy-carter/
http://en.wikipedia.org/wiki/Colors_of_noise#White_noise
White noise[edit]
Main article:
White noise
White noise spectrum. Flat power spectrum.
(logarithmic frequency axis)
White noise is a
signal (or process), named by analogy to
white light, with a flat
frequency spectrum[1] when plotted as a linear function of frequency (e.g., in Hz). In other words, the signal has equal
power in any band of a given
bandwidth (
power spectral density) when the bandwidth is measured in
Hz. For example, with a white noise audio signal, the range of frequencies between 40
Hz and 60 Hz contains the same amount of sound power as the range between 400 Hz and 420 Hz, since both intervals are 20 Hz wide. Note that spectra are often plotted with a logarithmic frequency axis rather than a linear one, in which case equal physical widths on the printed or displayed plot do not all have the same bandwidth, with the same physical width covering more Hz at higher frequencies than at lower frequencies. In this case a white noise spectrum that is equally sampled in the logarithm of frequency (i.e., equally sampled on the X axis) will slope upwards at higher frequencies rather than being flat. However it is not unusual in practice for spectra to be calculated using linearly-spaced frequency samples but plotted on a logarithmic frequency axis, potentially leading to misunderstandings and confusion if the distinction between equally spaced linear frequency samples and equally spaced logarithmic frequency samples is not kept in mind.
[2]
Pink noise[edit]
Pink noise spectrum. Power density falls off at 10 dB/decade (−3 dB/octave).
The frequency spectrum of
pink noise is linear in
logarithmic space; it has equal power in bands that are proportionally wide.
[1][3] This means that pink noise would have equal power in the frequency range from 40 to 60 Hz as in the band from 4000 to 6000 Hz. Since humans hear in such a proportional space, where a doubling of frequency (an octave) is perceived the same regardless of actual frequency (40–60 Hz is heard as the same interval and distance as 4000–6000 Hz), every octave contains the same amount of energy and thus pink noise is often used as a reference signal in
audio engineering. The
power density, compared with white noise, decreases by 3
dB per
octave (density proportional to 1/
f ). For this reason, pink noise is often called "1/
f noise".
Since there are an infinite number of logarithmic bands at both the low frequency (DC) and high frequency ends of the spectrum, any finite energy spectrum must have less energy than pink noise at both ends. Pink noise is the only power-law spectral density that has this property: all steeper power-law spectra are finite if integrated to the high-frequency end, and all flatter power-law spectra are finite if integrated to the DC, low-frequency limit.
Brown(ian) noise[edit]
Main article:
Brownian noise
Brown spectrum (−6 dB/octave)
In fields that adopt precise definitions, the terminology "red noise", also called Brown noise or
Brownian noise, will usually refer to a power density which decreases 6 dB per octave with increasing frequency (density proportional to 1/
f 2)
[1] over a frequency range which does not include
DC (in a general sense, does not include a constant component, or value at zero frequency). In areas where terminology is used loosely, "red noise" may refer to any system where power density decreases with increasing frequency.
[4]
The first definition can be generated by an algorithm which simulates
Brownian motion or by
integrating white noise. "Brown" noise is not named for a power spectrum that suggests the colour brown; rather, the name is a corruption of Brownian motion. "Red noise" describes the shape of the power spectrum, with pink being between red and white. Also known as "random walk" or "drunkard's walk" noise.
Blue noise[edit]
Blue spectrum (+3 dB/octave)
Blue noise is also called azure noise. Blue noise's power density increases 3 dB per octave with increasing frequency (density proportional to
f ) over a finite frequency range.
[1][5] In computer graphics, the term "blue noise" is sometimes used more loosely as any noise with minimal low frequency components and no concentrated spikes in energy. This can be good noise for
dithering.
[6] Retinal cells are arranged in a blue-noise-like pattern which yields good visual resolution.
[6][7]
Violet noise[edit]
Violet spectrum (+6 dB/octave)
Violet noise is also called purple noise. Violet noise's power density increases 6 dB per octave with increasing frequency
[1][8][9] (density proportional to
f 2) over a finite frequency range. It is also known as
differentiated white noise, due to its being the result of the differentiation of a white noise signal.
Grey noise[edit]
Grey noise is random white noise subjected to a psychoacoustic equal loudness curve (such as an inverted
A-weighting curve) over a given range of frequencies, giving the listener the perception that it is equally loud at all frequencies.
[citation needed] This is in contrast to standard white noise which has equal strength over a linear scale of frequencies but is not perceived as being equally loud due to biases in the human
equal-loudness contour.
It dawned on me the other day that there is a lot of people out there that do not know the difference between white noise and pink noise. So I decided to give a little explanation on the subject, with some sound and pictures to go along.
As well, I figured it might be important to young producers who might have read somewhere to use “white noise” in their songs (like everybody else in EDM nowadays) but are curious to know exactly what it is.
So what is white noise?
White noise is a random signal with a flat power spectral density. In other words, the signal contains equal power within a fixed bandwidth at any center frequency or equal energy per frequency. The fact that it has equal energy per frequency is very important to remember when trying to explain the difference between the two (I often forget so please don’t quiz me if you ever bump into me in the streets)
I have uploaded a 5 second clip of white noise (it’s downloadable in case you feel like doing something with it). Here’s what it sounds like:
White Noise
Just sounds like random shit eh? Well now try listening to pink noise (downloadable) as well and see if you can tell the difference.
*Note* I have color co-ordinated the players in case you are deaf, which in that case, it would be pointless for you to try to listen to them.
Pink Noise
See there is a slight difference and now I’ll explain what pink noise is.
Pink noise is a random signal with a frequency spectrum such that the power spectral density (energy or power per Hz) is inversely proportional to the frequency or equal energy per octave.
White noise is equal energy per frequency. Let’s look at a 3D analysis of my white noise followed by a spectrum analysis
And the spectrum analysis
Looks somewhat even right? This is because with white noise, no matter what frequency in the frequency spectrum, the same amount of energy is present.
But now let’s take a look at a 3D analysis and the spectrum image of my pink noise.
And the spectrum of the pink noise
If you notice, it looks like its getting weaker as you go from low frequencies to high frequencies. This is because the farther up you go in the frequency range the more the energy is spread out. So for example lets start at 440hz A. The next octave lower starts at 220hz and the next one higher is at 880hz (its always half the hz for the previous octave or double the hz for the next octave). So although there is only 220hz in the lower octave and 440hz in the higher octave they both have the same amount of energy within them, so it must be distributed differently at each frequency.
To really clarify this if you can imagine that the frequency range of 27.5hz-55hz contains the exact same amount of energy as the frequency range of 7040hz-14080hz in pink noise, you should understand what I mean.. But you can see that in the pics (which is why I included them!)
So why don’t producers choose to use pink noise rather than white noise? Well my guess is because in the higher frequencies, pink noise doesn’t nearly have as much energy as white noise and you generally cut the lows out of white noise or any kind of transistion fx (in most cases). I think if you did the same thing to pink noise you would be left with a tinny sounding powerless thing as the meat is in the lows (I haven’t tried that out).
So what’s pink noise good for then? Sound guys use it to test whether sound systems have a flat frequency response in the spectrum of their interest. And also I think when you turn on the tv late at night once a station is off the air, what you’re hearing is pink noise (but I’m really not sure).
Oh and there’s another type of noise I decided I like to talk about since normally you only hear about whiteand pink noise. There is also brown noise. It’s a random signal as well but it decreases in power by 6db per octave. And to put in to terms what “6db” means, it pretty much means that its half as loud every octave. So it gets quiet pretty quickly in the higher frequencies. I’ve uploaded a small 5 sec clip (again downloadable) for you to hear what it sounds like.
Brown Noise
No pictures or anything for this one. Not that I can’t provide them. I’m just too lazy and don’t really feel like it.
So remember…
White noise = Equal energy per frequency
Pink noise = Equal energy per octave
Brown noise = -6db per octave
Purple noise = +6db per octave
Loudspeaker
http://en.wikipedia.org/wiki/Loudspeaker
http://electronics.howstuffworks.com/speaker7.htm
http://answers.yahoo.com/question/index?qid=20080410074611AAXDHzH
http://www.differencebetween.net/object/difference-between-woofer-and-subwoofer/
http://www.ehow.com/facts_7662281_difference-between-woofer-subwoofer.html
Driver Types
In the last section, we saw that traditional speakers produce sound by pushing and pulling an electromagnet attached to a flexible cone. Although drivers are all based on the same concept, there is a wide range in driver size and power. The basic driver types are:
- Woofers
- Tweeters
- Midrange
Woofers are the biggest drivers, and are designed to produce low frequency sounds. Tweeters are much smaller units, designed to produce the highest frequencies. Midrange speakers produce a range of frequencies in the middle of the sound spectrum.
Ben S answered 6 years ago
There are different types of speakers designed to play different frequencies which humans can hear (typically 20Hz - 20,000Hz)
Subwoofers are the largest of these three types and plays the lowest frequencies, known as the sub-bass range from about 20 - 30Hz to around 80 - 100Hz. These are usually located in the boot of the car as the enclosure can take up a lot of space.
Next is the mid-bass range which is reproduced by your normal speakers that you would find in your doors. these can range in size from 4" to 7" and reproduce the frequencies between 100Hz to about 5000Hz but this largely depends on the tweeter.
Finally the tweeter, it is the smallest of the three and is designed to play the highest frequencies, also known as the treble from 5000Hz to 20,000Hz. Again this largely depends on the tweeter itself. People usually put these high on the doors or on the dash to raise the "stage height"
IID And ITD
http://www.cs.sfu.ca/~tamaras/localization/ITD_IID_Cues.html
