In fluids such as air and water, sound waves propagate as disturbances in the ambient pressure level.

The loudness of these disturbances is called the sound pressure level ( SPL ), and is measured on a logarithmic scale in decibels.

) or " plus or minus 1dB " ( roughly the sound level difference people usually can detect ).

It is used primarily in its decadic fraction, the decibel ( dB ), for signal strength and sound pressure level measurements, while a unit for one tenth of a byte, i. e. the decibyte, is never used.

Players were patiently refined until fundamentally sound instead of being hastily advanced to the next level.

Programming features such as randomization, variables, and intermap script activation enable smooth hub gameplay and are responsible for most of the special effects within the game: On-screen messages ; random sound effect and monster spawning ; sidedef texture changes ; versatile control of polyobjects ; level initialization for deathmatch ; and even complex environment changes such as earthquakes manipulating floor levels and textures.

Around the year 1900 Lord Rayleigh developed the duplex ( combination of two ) theory of human sound localization using two binaural cues, interaural phase difference ( IPD ) and interaural level difference ( ILD ) ( based on analysis of a spherical head with no external pinnae ).

The theory posits that we use two primary cues for sound lateralization, using the difference in the phases of sinusoidal components of the sound and the difference in amplitude ( level ) between the two ears.

However, as a result of conservative fiscal policies and a sound financial system, in 2010 the country credit rating improved slightly to BB + and was kept at that level in 2011.

The frequency of a filter and the envelope attack, or the time it takes for a sound to reach its maximum level, are examples of synthesizer parameters, and can be controlled remotely through MIDI.

Audio control surfaces often resemble mixing consoles in appearance, and enable a level of hands-on control for changing parameters such as sound levels and effects applied to individual tracks of a multitrack recording or live performance output.

When morphemes combine, they influence each other's sound structure ( whether analyzed at a phonetic or phonemic level ), resulting in different variant pronunciations for the same morpheme.

* The maximum sound level achievable was quite limited, being limited to the physical amplification effects of the horn,

There were some user made level editors, a random level generator from Apogee, maps, sound files, etc.

One problem with acoustic stethoscopes was that the sound level is extremely low.

As the more complex sound signal is broken into the smaller sub-sounds, different levels are created, where at the top level we have complex sounds, which are made of simpler sounds on lower level, and going to lower levels even more, we create more basic and shorter and simpler sounds.

The lowest level, where the sounds are the most fundamental, a machine would check for simple and more probabilistic rules of what sound should represent.

Once these sounds are put together into more complex sound on upper level, a new set of more deterministic rules should predict what new complex sound should represent.

At this point, a second layer of nodes represents higher level features of a sound input which is again statistically evaluated to see what class they belong to.

Last level of nodes should be output nodes that tell us with high probability what original sound really was.

The earliest of viols would also have had the ends of their fretboards flat on the deck, level with or resting upon the top or sound board.

It is unknown how the sound level of a toroidal whistle would compare to that of a high frequency conventional plain whistle of the same diameter.

Above all though, the Satyr with flute has a small companion for him, shows the deep connection with nature, the soft whistle of the wind, the sound of gurgling water of the crystal spring, the birds singing, or perhaps the singing a melody of a human soul that feeds higher feelings.

A dog whistle exploits this by emitting a high frequency sound to call to a dog.

Many dog whistles emit sound in the upper audible range of humans, but some, such as the silent whistle, emit ultrasound at a frequency in the range 18 – 22 kHz.

Clarke style rolled metal whistles tend to have an airy " impure " sound, while Generation style cylindrical instruments tend to have clear or " pure " whistle sounds.

Kwela is the only music genre created around the sound of the tin whistle.

A whistle or call is a simple aerophone, an instrument which produces sound from a stream of forced air.

A whistle may also contain a small light ball, usually called the pea, which rattles around inside, creating a chaotic vibrato effect that intensifies the sound.

A steam whistle works the same way, but using steam as a source of pressure: such whistles can produce extremely high sound intensities.

The Fox 40 whistle is a pealess whistle which creates sound using air pressure only.

The traditional samba whistle has three tones, but as the size of the percussion section rose, pealess whistles became more popular due to their high pitch and their loud sound.

The lyrebird is capable of imitating almost any sound and they have been recorded mimicking human caused sounds such as a mill whistle to a cross-cut saw, chainsaws, car engines and car alarms, fire alarms, rifle-shots, camera shutters, dogs barking, crying babies, music, and even the human voice.

A civil defense siren ( also referred to as an air raid, civil defence, tornado, tsunami, fire, flood, weather, time, curfew, earthquake, storm, police, emergency, hurricane, or other outdoor warning siren / whistle / horn / alarm ) is a mechanical or electronic device ( modern-day sirens are electrically powered whether they are electronic or electro-mechanical ) for generating sound to provide warning of approaching danger and sometimes to indicate when the danger has passed.

It is a subset of the much older International Code of Signals ( INTERCO ), which originally included visual signals by flags or flashing light, sound signals by whistle, siren, foghorn, or bell, as well as one, two, or three letter codes for many phrases.

The whistle punk's job was to sound a whistle as a signal to the yarder operator controlling the movement of logs and act as a safety lookout, and a good whistle punk had to be alert and think fast as the safety of the others depended on him.

However, he is dull-witted and has a weakness: the sound of a bell makes him dance, and he cannot stop dancing until he hears a whistle.

The modern slide whistle is perhaps most familiar in its use as a sound effect ( as in the sound tracks of animated cartoons, when a glissando can suggest something rapidly ascending or falling, or when a player hits a " Bankrupt " on Wheel of Fortune ), but it is also possible to play melodies on the slide whistle.

Its whistle blew loudly as it neared Castor River, the sound echoed over the distant hills, a signal to the mail carrier, the draymen and anyone else who might want to meet the train.

The sound of a hawk's whistle or scream makes the iguana freeze and it becomes easier to capture.

A drum would sound the simultaneous attack, and a whistle would signal that Kira was dead.