'Soundproofing' or 'sound isolation' - which is correct?

Some people talk about soundproofing, others about sound isolation. But which is correct? And what about sound insulation - is that correct too?

By David Mellor, Course Director of Audio Masterclass

We received a comment recently saying that where we mention soundproofing at Audio Masterclass we should use the term 'sound isolation' instead, which is supposedly more correct.

Well the short answer to that is that we tested both terms in the marketplace a few years ago, and our results showed that vastly more people were interested in The Audio Masterclass Guide to Soundproofing, than they were in The Audio Masterclass Guide to Sound Isolation.

So we use soundproofing because most people readily understand what it implies. And when we talk about soundproofing, we explain what it really means (and how it is a different concept to acoustic treatment).

Sound isolation is however a useful term in the sense of being a desirable state to achieve.

So if for instance a studio has an isolation booth, then the implication is that sound from outside the booth doesn't get in, and sound from inside of the booth doesn't get out.

Perfect sound isolation is however extremely difficult to achieve in practice, to the point that you could never say that a booth is completely isolated and actually soundproof.

Sound insulation is an expression that is often used to mean the process of achieving sound isolation.

So you could design a booth with a modest amount of sound insulation. When constructed, you would call this your 'isolation booth'. It would be neither completely isolated nor soundproof, but it would provide a certain amount of separation from the main recording area and you would find it useful.

If in future you wanted to upgrade the degree of isolation, you would upgrade the insulation by thickening the walls, improving the seals and blocking any transmission paths.

To be honest, more important than worrying about fine distinctions between soundproofing, sound isolation and sound insulation is to understand the difficulty of achieving an effective degree of soundproofing or sound isolation. For this reason it is important to seek expert advice, otherwise a considerable amount of time, effort and money could be wasted.

Having said that, we did find two examples of places that are completely soundproof to the world...

This...

and this!