USING REVERB
Reverberation is the result of the many reflections of a sound that occur in a room. From any sound source, say a speaker of your stereo, there is a direct path that the sounds covers to reach our ears. But that's not the only way the sound can reach us. Sound waves can also take a slightly longer path by reflecting off a wall or the ceiling, before arriving at your ears. A reflected sound wave like this will arrive a little later than the direct sound, since it travels a longer distance, and is generally a little weaker, as the walls and other surfaces in the room will absorb some of the sound energy. Of course, these reflected waves can again bounce off another wall before arriving at your ears, and so on. This series of delayed and attenuated sound waves is what we call reverb, and this is what creates the 'spaciousness' of a room. |
BELOW IS A VISUAL DIAGRAM 2 GIVE YOU AN EXAMPLE OF HOW REVERB WORKS
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It's very tempting to say that reverb a series of echoes, but this isn't quite correct. 'Echo' generally implies a distinct, delayed version of a sound, as you would hear with a delay more than one or two-tenths of a second. With reverb, each delayed sound wave arrives in such a short period of time that we do not perceive each reflection as a copy of the original sound. Even though we can't discern every reflection, we still hear the effect that the entire series of reflections has. So far, it sounds like a simple delay device with feedback might produce reverberation. Although a delay can add a similar effect, there is one very important feature that a simple delay unit will not produce - the rate of arriving reflections changes over time, whereas the delay can only simulate reflections with a fixed time interval between them. In reverb, for a short period after the direct sound, there is generally a set of well defined and directional reflections that are directly related to the shape and size of the room, as well as the position of the source and listener in the room. These are the early reflections (also called the 'early echoes' despite the general meaning of the word 'echo'). After the early reflections, the rate of the arriving reflections increases greatly. These reflections are more random and difficult to relate to the physical characteristics of the room. This is called the diffuse reverberation, or the late reflections. It is believed that the diffuse reverberation is the primary factor establishing a room's 'size', and it decays exponentially in good concert halls. Once you've created space in your mix, don't give it all away by filling every available gap with heavy reverb. As it happens, reverb is one area where a decent-quality unit really helps, especially if you use a lot of small-room or ambient reverbs. You don't have to spend a fortune: the excellent Lexicon MPX100 costs around $200, yet still offers the general feel of Lexicon's more expensive studio processors. Bear in mind that heavy reverb tends to push a sound to the back of a mix, so if you want a vocal to appear up-front you should use a fairly bright reverb, with 80mS or so of pre-delay. Don't overdo the decay time, either, especially with up-tempo songs. Other effects should also be used carefully -- use an effect because the track needs it, not because you happen to have it! Dramatic effects can be made even more dramatic if you use them for short sections of a song rather than having them full-on all the way through, and delay effects often work best when the delay time is related to the tempo of the song. |
