M-Audio WizooVerb W2 [27/132] What causes reverberation

What Causes Reverberation?

English

Courtesy of this combination, WizooVerb W2 offers unprecedented pro-

cessing options and surprising ﬂexibility, as well as outstanding sound

quality.

The following of rule of thumb applies to WizooVerb: HDIR is the best choice when you

want to accurately replicate a real room (natural reverb). AIR is the preferred choice if

you want more editing options or need to conserve computer performance. Because

the principles behind the modes are so different, each offers very different creative

possibilities that are explained fully in the following chapters. In beiden Modi haben

Sie prinzipbedingt unterschiedliche kreative Möglichkeiten, die später noch weiter

unten ausführlich erklärt werden.

What Causes Reverberation?

Let’s review some basic acoustics.

When a sound source sends an acoustic wave out into a room, it is re-

ﬂected as well as absorbed by the walls, ceiling and ﬂoor, as well as by all

the objects in the room.

Reﬂection: If the direct path between the sound source and listener is un-

obstructed, the direct sound arrives at the ear ﬁrst. It is followed by early re-

ﬂections that rapidly condense to form the tail. Reverberation can be di-

vided into three phases, depending on the time of the reﬂections’ arrival.

Though one phase morphs smoothly and seamlessly into the next, each

can have a varying impact on our perceptions:

❖ Reﬂections up to about 20 ms are largely perceived as unpleasant color-

ing.

❖ Reﬂections up about 20 to 50 ms serve to create a sense of spatiality,

that is, a room.

❖ After about 50 ms, reﬂections usually have condensed to create the dif-

fuse tail.

Absorption: Sound loses energy with every reﬂection so that towards the

end the tail tapers off gently. The time elapsing between the direct sound

and the tail’s decay is called reverberation or reverb time.

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