Space and Reverb

When the material already carries space, decide whether you want one room or two before adding reverb.

Related

ReverbStereo TechniquePhase Check

The problem

AI material often arrives with space attached. There is a hall behind the vocal, a room behind the drums, pedal and studio tail on the piano. Many people miss it, add a reverb, and stack two spaces until the mix turns to wash. Whether to add anything, and how much, starts with identifying what is already there.

How it works

Reverb divides into early reflections and a tail. Early reflections tell you distance and room size; the tail tells you length. More reverb does not mean more space; too much pushes every instrument behind the same wall. Space in AI material is usually generated as a whole, so the early reflections do not match the instrument positions while the tail runs long. Adding another reverb gives one event two timelines, blurring attacks and closing the gaps between words. Low-frequency tails also pile up near 200 Hz and make everything dull.

Practice

Listen to the dry signal or the stems and locate the existing space. A separated track has usually had its tail shaved, so a short room can help, with 10 to 20 ms of pre-delay and a 0.8 to 1.2 second decay. If the source already has a long tail, do not add a long reverb; at most use a little early reflection to restore distance. When the space must be unified, send every track to one reverb and let send level set the depth. Keep it to two reverbs per song, with pre-delays within 10 ms of each other, or the space splits. High-pass the send at 200 to 300 Hz to keep the low end out. Automate the amount, using less in the chorus to preserve clarity.

What to listen for

In Mahler's In diesem Wetter, hear whether voice and piano share one space, since two spaces expose themselves immediately. In the slow movement of Haydn's Sonata in E-flat, hear the ratio between the close piano and the pedal decay. In Satie's Gymnopedie No. 3, hear the air between sparse chords, which turns to wash when overdone. Start from the dry signal in all three.

Sources

• 早期反射与尾音的区分，依混响与空间处理通识核对，未抄文本
• Early reflections and decay tails, based on general reverb and spatial practice, no text copied

Used for fact-checking only; all prose is original.