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Entries found for search: echo

anechoic : Without echo. Said of an acoustic which is free-field, and specifically of a room which is designed to produce no reverberation or other echo effects. This is achieved by giving the walls very irregular surfaces of considerable and varying depths so that, in theory, all sound waves which strike them are completely absorbed and not reflected. Anechoic chambers are used to test audio equipment and for other types of acoustic and electromagneticelectro-magnetic research.

echo : An audio effect which is a discrete (where the onset of the repeated sound is distinct) repetition of a sound arriving at least 50ms after the incident sound, as opposed to reverberation, which is a continuous wash of closely spaced, non-discrete, echoing sound. See delay(3).

flutter echo : An acoustic effect where sound is reflected back and forth between two parallel surfaces such as walls. The same effect as standing waves, but at lower frequencies, flutter echo is created when reflections are lower than 15Hz, or when walls are greater than 25’ apart."

MIDI Echo : A feature that routes MIDI messages appearing at a device’s MIDI In-port through its processor, unaltered, to the MIDI Out port. This allows control of a MIDI sound module simultaneously from a sequencer and a keyboard. MIDI Echo differs from MIDI Thru in that there is a direct, hard-wired connection between the MIDI In and Thru jacks, so the datastream doesn’t pass through the device’s processor.

slap echo : The single repetition of a signal at a fixed time delay to simulate an echo from a single reflecting surface, as opposed to a multiple echo from a time delay, where the delayed signal is repeatedly fed back into the delay input. The sound is repeated once or twice only, with a short delay of 40-60ms.

pre-echo : (1) Depending upon the width of each frequency band in a transform coding scheme, it is possible for the decoder to produce variable amounts of pre-echo. For example, a sudden transient that has its rising edge contained within a frequency band:. The codec quite correctly detects the transient’sits presence and codes the information within the appropriate band, and also uses that information to re-use bits from surrounding masked envelopes. Upon decoding, the output level is turned on the for complete duration of the coded frequency band, which means that the signal will be heard before the arrival of the actual transient. Such pre-echoes sound very much like analog tape print-through and may produce unacceptable results, particularly on material containing large numbers of sharp level excursions. (2) In room acoustics, any early reflections of sound that occur within about 40 ms, the shortest time for which the ear can distinguish two non-simultaneous sounds. Some digital reverb devices include simulated pre-echoes as a part of their hall simulation program."

tape echo : An early method of producing echo effects by means of a tape loop. See loop(2).

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