Yamaha RX-V620RDS owner manual Sound Field Program Parameter Editing, What is a sound field?

SOUND FIELD PROGRAM PARAMETER EDITING

What is a sound field?

What really creates the rich, full tones of a live instrument are the multiple reflections from the walls of the room. In addition to making the sound “live”, these reflections enable us to tell where the player is situated, and the size and shape of the room in which we are sitting.

■Elements of a sound field

In any environment, in addition to the direct sound coming straight to our ears from the player’s instrument, there are two distinct types of sound reflections that combine to make up the sound field:

Early reflections

Reflected sounds reach our ears extremely rapidly

(50 ms – 100 ms after the direct sound), after reflecting from one surface only — for example, from the ceiling or a wall. These reflections fall into specific patterns for any particular environment, and provide vital information to our ears. Early reflections actually add clarity to the direct sound.

Reverberations

These are caused by reflections from more than one surface — walls, ceiling, the back of the room — so numerous that they merge together to form a continuous sonic “afterglow”. They are non-directional, and lessen the clarity of the direct sound.

Direct sound, early reflections and subsequent reverberation taken together help us to determine the subjective size and shape of the room, and it is this information that the digital sound field processor reproduces in order to create sound fields.

If you could create the appropriate early reflections and subsequent reverberations in your listening room, you would be able to create your own listening environment. The acoustics in your room could be changed to those of a concert hall, a dance floor, or virtually any size room at all. This ability to create sound fields at will is exactly what YAMAHA has done with the digital sound field processor.

Sound Field Program Parameters

DSP programs consist of some parameters to determine the apparent room size, reverberation time, distance from you to the performer, etc. In each program, these parameters are set with values precisely calculated by YAMAHA to create a sound field unique to the program. It is recommended to use DSP programs without changing the values of parameters; however, this unit also allows you to create your own sound fields. Starting with one of the built-in programs, you can adjust those parameters.

Each DSP program has a set of parameters that allow you to change the characteristics of the acoustic environment to precisely create the effect you want. These parameters correspond to the many natural acoustic factors that create the sound field you experience in an actual concert hall or other listening environment. The size of the room, for example, affects the length of time between the early reflections. The “ROOM SIZE” parameter provided in many of the DSP programs alters the timing between these reflections, thus changing the shape of the “room” you are listening. In addition to room size, the shape of the room and the characteristics of its surfaces have a significant effect on the final sound. Surfaces that absorb sound, for example, cause the reflections and reverberations to die out more quickly, while highly reflective surfaces allow the reflections to carry on for a longer period of time. The digital sound field parameters allow you to control these and many other factors that contribute to your personal sound field, allowing you to essentially “redesign” the concert halls, theaters, etc. provided to create custom-tailored listening environments that ideally match your mood and music.

See “Sound Field Parameter Descriptions”.

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