Unit 25: Sound recording- Noran

digital audio- is technology that can be used in sound recording and reproduction systems. It will record, store, generate, manipulate and reproduce sound using audio signals encoded in digital form. 

analogue- a wave is recorded or used in its original form. An analog recording is one where a property or characteristics of a physical recording medium is made to vary in a manner analogous to the variations in air pressure of the original sound. 

Audio signal path/flow- the order of operations a sound goes through. when you record an instrument, the sound goes through different stages before you hear it through speaker/headphones. 

sound-microphone-audio need-recorder import-record amplifier-

SD card-hard drive-converter- 

Sound levels game- sound is measured in decibels (db) 

Recording levels- audio levels should stay on the negative side of the number scale should never go above 0 (db). If it goes above 0 it will have audio distribution. -10/-12 for recording person audio. Crazy environment drop the db. If a person gets louder you will drop the db. 

Sound file format- (mp3) formats or audio codecs are those strange file names.

What are the two types of signal paths and what is the difference?

the two types of signal paths are digital audio and analogue. The difference between them are digital audio will record, store, generate, manipulate and reproduce sound using encoded in digital form whereas, analogue is where a property of characteristics of a physical recording is made to vary in a manner of analogue to the variations in the air pressure of the original sound. 

uncompressed file formats-

- Broadcast wave format (BWF or BWAV)

- pc standard

- waveform audio format (WAV)

- Mac standard

- audio interchange file format (AIFF)

- pulse-code modulation (PCM)

- compact disc digital audio (CDDA) 

lossless audio- This is a compression technique that decompresses audio files back to their original data amount. Lossless methods can provide high degrees of digital compression, but there is no loss in size or sound quality. 

- ATRAC

- apple.m4a

- MPEG-4

- WMA 

Lossy- the original bit depth is reduced to remove data and reduce the file size. The bit depth becomes variable. 

- MP3

- Vorbis

- ATRAC lossy

- WMA

Types of sound recording set ups:

- portable/ battery operated, (field/ location recording, interior and exterior, custom recordings).

-studio/ mains operated application, (studio recording, recording software for computers).

Field recording is the term used for an audio recording produced outside of a recording studio, and the term applies to recordings of both natural and human-produced sounds. - Lavaliers mics are really good at capturing sound as long as they are not to close to a person speaking and which is why they are good for outside recording as they can pick up natural sounds the best. Lavaliers are small and portable, making them useful for on the go recordings. the microphone considered to be the best for field recording is a dynamic microphone which are great for recording anywhere- omni directional. 

Hypercardioid and Supercardioid Microphones are powerful condenser microphones that record sound coming in from the front and sides, not from the rear. Shotgun mics are a good example of this type of microphone. They are useful in outdoor situations because they reject sound from the rear.Location sound recording is a production sound mixer, location sound recordist, location sound engineer or simply sound mixer is the member of a film crew or television crew responsible for recording all sound recording on set during the filmmaking or television production using professional audio equipment.

There are many good studio recording software's that can be used including Audacity which is available for Mac and PC, and is a popular choice for free audio software. 

Recording level measurements:

- A VU meter is used to measure power levels of audio frequency signals. Such meters employ special ballistics that average out complex waveforms to properly indicate program material that varies simultaneously in both amplitude and frequency.

- A PPM meter is a peak programme meter (PPM) is an instrument used in professional audio that indicates the level of an audio signal.

 The difference between the two are that a VU meter displays the average volume level of an audio signal. A PPM displays the peak volume level of an audio signal. ... But for a complex audio signal (speech or music), the difference between the average level (VU) and the peak level (PPM) can be 10 to 12 dB!

Frequency response is measured in Hertz, it defines the range of sound that a microphone can reproduce and how its output varies within that range. The frequency response is the most significant factor is determining the sound signature of a microphone. the frequency response of a mic is represented graphically by a response curve. the two most common types are flat response and shaped, or tailored, response. 

1/4 Mono jack, guitars, keyboard, right angle version, used for instruments, speaker cables.

1/4 Stereo jack, connect to a stereo output, mixing desk, balance cable, guitar amps.

Stereo mini jack, headphone sockets, plug phone/tablet in a amplifier, input/output plug.

Phono, video input/output.

3-pin XLR connector, male (input) three sticks/female (output)three wholes connector, connect more than one cable together, long cable runs, used for microphones and speakers. 

Speakon connector, connecting speaker to amplifiers, female- speaker cable, male, use screwed in connections.

The main problem when recording outside would be the sound of the wind, to solve this you will place a windshield on the microphone which will help prevent the wind from being heard in the background. 

Reverb, (short for reverberation) is the acoustic sound environment that surrounds a sound. Natural reverb exists everywhere. Whether the space being described is a bathroom or a gymnasium; the essential characteristics. 

cite this for me- referencing

• The Doppler effect, sound object moves towards you (ambulance coming closer becoming louder), higher pitch, sound waves decrease when moving away.
• Sound radiation- energy moves to one place to another, speaker playing music the sound is radiating into your air shows the way it is moving. 

Behaviour of sound at different altitude 

- sound can move through water faster than through air

Waves does not stop when it hits an obstacle.

Reflection- when the sound waves bounces off the object, creating an echo, occurs of hard surfaces, sound wave can not get far into the surface (concrete, brick). 

Refraction- change in the direction of waves passing through different mediums.

Absorption- sound waves are 'trapped' by the object, where its energy is transformed into a small amount of heat. soft objects (soft furnishing sofas cushion) pillows absorb sound wave to turn into heat.

sound frequency- Frequency, sometimes referred to as pitch, is the number of times per second that a sound pressure wave repeats itself. ... The units of frequency are called hertz (Hz). Humans with normal hearing can hear sounds between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz are known as ultrasound.

Octaves- the measure of distance between two notes 

Harmonics- unwanted higher frequencies which overlay on the fundamental waveform creating a distorted wave pattern.

How is sound transmitted through the different mediums:

- walls

- glass

- water

- air  

 

Sound is transmitted through different types of mediums. Sound transmitted through walls if sound is placed next to the surface, you will then get some of the acoustic energy will reflect/ bounce back off of the wall. As a wall is a solid, when sound hits the wall it will vibrate to the other side. 

Sound being transmitted through glass transmits energy as it has low frequencies. Sound travels faster through glass than air as the glass material is much denser than air. When travelling through glass molecules compress against on another. The molecules are more rigid which causes sound to travel faster. 

Sound travelling through water the sound passes through and vibrates into your head. However, when the sound is above the surface it vibrates only into the eardrum, depending on how loud the sound is. Sound travels roughy around 1,480 metres per second in water, compared to air travelling at 343 meters per second. 

Sound traveled through air is an energy which is made by vibrations. Vibrations are made by movements of different particles. The sound carries on until the particles run out of energy. 

 

Different sound recordings

https://docs.google.com/document/d/1XXRDYwA82_qLqK0FMmAjcFbLdVh4DOY3VlRZiQ_DUac/edit?usp=sharing