Short definition
Sound insulation prevents sound from passing from one room into another – for example, between an interpreting booth and the hall, or between neighboring booths.
Detailed explanation
While absorption improves sound within a room, insulation is about separating two areas. A well-insulated interpreting booth ensures interpreters hear the hall only through their headphones – not raw through the walls – and, conversely, that their own voice doesn't leak into the hall or the neighboring booth.
This is critical at multilingual events: if several booths sat side by side without insulation, the interpreting languages would interfere with each other. That's exactly why ISO 2603 (fixed booths) and ISO 4043 (mobile booths) define minimum values for sound insulation. For mobile booths, this insulation is the key difference between a standard-compliant "real" booth and a makeshift table or partition setup.
Relevance in this subject area
Without adequate insulation, clean simultaneous interpreting with multiple languages isn't possible. It's the basic prerequisite for booths to work side by side at all.
Practical example
At a five-language conference, five mobile booths stand in a row. Thanks to ISO 4043-compliant sound insulation, no booth interferes with another – each language stays cleanly separated.
Related terms
Sound absorption, Interpreting booth, ISO 2603, ISO 4043, Simultaneous interpreting