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Now looking at definitions starting with letter "h"

Haas effect : The Haas Effect refers to the brainís ability to integrate incident sound and early reflections into a single sound. Those early arrivals which occur within the first 5-35ms that are not more than about 10dB louder than the direct sound will be combined and added to the first arrival and localized to its source. If the delayed sound is more than 10dB louder or the delay is greater than 35ms, the listener will perceive distinct echoes.A psychoacoustic phenomenon where an instrument or soundís apparent localization will shift in the direction of the earliest signal. This is a type of sensory inhibition which causes the response to the direct sound source to inhibit response to the reflections. Haas further noted the Precedence Effect: the position of a perceived sonic image created by two sound sources depends on both the arrival times and the relative levels. If two sound sources arrive at the same time and at the same level, human aural perception will image the sound toward the centerpoint between the two sounds. If two sounds are equally loud, the image will shift toward the earliest-arriving signal. Further, if one source is louder, the image can be moved back to the center between the two sources by adding delay, provided that the delay time is less than 25ms. Beyond 25-30ms, the ear begins to hear the delayed sound as a discrete echo and the image shift effect no longer works. This phenomenon is usually used to simulate a stereo image in a monophonic recording where the original signal is panned hard left and a copy is delayed (1-50ms delay) and panned hard right. The Precedence Haas Eeffect may be mitigated by slightly attenuating the volume of the dry sound.

half track : (1) A recording format in which two parallel tracks are recorded in a single pass on a tape, each track using slightly less than half of the tape width. On some machines, a very narrow track with SMPTE or other synchronizing information is recorded and reproduced in the guard band. In this case, the data is frequency-modulated onto a very high-frequency tone in order to minimize crosstalk or bleeding into the audio. (2) A tape machine which records on half of the tape width only. This allows the tape to be inverted at the end of its play time, doubling the recording time for a given length of tape. See also two-track, four-track."

half-space loading : The placement of a loudspeaker against a wall or other hard, reflective surface. Such a placement typically improves the performance of a loudspeaker, enabling a wider dynamic range, as well as improving the amplitude response of the speaker. An alternative to placing the loudspeaker in a free-field.

half-step : The musical interval of a minor second in a diatonic scale, equal to 100 cents. In equal temperament, there are twelve semitones in each octave, so in the equal tempered scale, the minor second has a frequency ratio of the , or about 6%. In just intonation, the minor second has a frequency ratio of 15/16 . Also called a semitone. See scale.

half-time : See alla breve.

handles : Sound sections between works in a production track that enable the re-recording mixer to cross-fade smoothly between shots with different backgrounds and/or room tones.

handshaking : In data transmission, the process of checking that a receiving device is ready to receive, or that a transmitting device is ready to transmit. Also, the method whereby such checking takes place. In MIDI, handshaking occurs in System-Exclusive, where messages are sent between two devices to ensure that both are present and that both have received or transmitted blocks of data.

hang : In film, the act of playing back a given element during a mix for the purposes of adding the track(s) to the mix. "We wonít premix the Foley cloth but will hang it at the final mix instead."

hangover : The resonance which continues in a loudspeaker cone after the input signal has stopped. See also damping factor, impulse response, ringing.

hard disk recording : A computer-based form of tapeless recording in which incoming audio is converted into digital data and stored on a hard disk. The digital counterpart to direct-to-disc analog (vinyl) recording, but being digital, the recording can be edited.

hard knee compression : A characteristic of certain designs of a compressor wherein nothing happens to an input signal until the signal reaches the threshold limit, but as soon as it does, the full level of gain reduction is applied, as determined by the ratio control setting. A graph of the input gain against the output gain will show a sharp change in slope at the threshold level. Compare with soft knee compression."

Hardware : Any tangible physical computing asset.

harmonic : A frequency that is a whole-number multiple of the fundamental. For example, if the fundamental frequency of the sound is 440Hz, then the first two harmonics are 880Hz and 1.32kHz. A harmonic is the same as a partial where the partials exhibit the property that the overtones are mathematical multiples of the fundamental frequency. See harmonic series, Appendix† C.

harmonic distortion : The onset of harmonic distortion is the displacement of energy from a single frequency to its harmonics. The presence of harmonic frequencies added to an output signal by an electrical circuit or speaker, generally undesirable, caused by the system not being perfectly linear, such as when an amplifier is operated in a nonlinear portion of its transfer curve. It is expressed as a percentage of the original signal:

(Total Signal - Fundamental Signal) THD = Total Signal In a perfect audio device, such as an amplifier or tape recorder, the output signal would be a replica of the input signal with no changes except possibly the amplitude of the signalmaybe power level. See also doubling.

harmonic enhancement : A technique used by aural enhancers. See harmonic synthesis."

harmonic envelope : The natural decay in the harmonics of a natural instrument over time.

harmonic series : A set of all of the frequencies which are an integral multiple of the frequency of the lowest tone, or fundamental. Humans perceive a harmonic series as a single pitch whose tonal quality is determined by the exact mix of related harmonics present. Below are illustrated the first sixteen harmonics in the harmonic series for the fundamental, C=65.4Hz. The notes indicating the 7th, 13th, 14th and 15th harmonics occur slightly flat or sharp of the notated pitch.See harmonic, partial.

harmonic series tuning : A tuning system which is based on the first sixty harmonics of the tonic, resulting in a tuning which is not based on the usual diatonic scale. There are more notes per octave as the tuning progresses up the harmonic series; the top 32 keys of a keyboard cover one octave in pitch.

harmonic structure : The sequence of chords used in a piece of music.

harmonic synthesis : A technique used by aural enhancers which creates new high-frequency harmonics not present in the original recording. Adding a small amount of carefully controlled distortion can make a sound quality appear cleaner and more detailed. This happens by sending some dry sound to a side-chain highpass filter. The output of the filter is processed dynamically to add phase-shift and create synthesized HF (only) harmonics related to the dry signal.

harmonizer : See pitch-shifter.

hat : See top hat.

haystack filter : See bell filter.

HBA : host bus adapter. Hardware that provides interface services, both at the PHY and logical layers, between some communication standard and a computerís operation system.

HCA : Host Channel Adapter. The IB component that connects a processor to other IB devices. An HCA is a bridge and must communicate with both other HCAs and TCAs. HCAs hookup, somehow, to your PC. Just how isnít yet established, though they may be integrated onto the motherboard, presenting and external physical connector for linking, it should allow I/O subsystems, like Ethernet, fibre Channel, SCSI and interprocessor communication to converse through the infiniBand switch fabric, without complex hardware or software interfaces.

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