Q: “More and more I am seeing the phrase ‘gold sputtered diaphragm’ with microphones. What’s the benefit of this?”
A: This is kind of a funny one to us. Gold is an extremely effective conductor of electricity, which is why you sometimes see it added to audio and video connectors. Sputtering is a technique for applying a molecular layer of atoms to a surface. A gold sputtered diaphragm therefore has a very thin layer of gold on its surface, which makes the surface a much better electrical conductor. The conductivity of the diaphragm surface is important to the manufacturing of condenser microphone capsules. By sputtering gold on the surface of some strong and lightweight material the diaphragm can remain very rigid, yet very agile in terms of being able to be quickly moved by small and/or sudden air movements (i.e. transients); and remain very efficient electrically, all of which are important for accuracy over a wide range of audio dynamics. Gold sputtered diaphragms have been around for many years, and in general are considered an essential part of any high quality condenser capsule. It has only become a marketing term in the last few years. In fact, it is because it’s essential and pretty much a given in condenser diaphragm manufacturing that most of the “old guard” mic manufacturers (AKG, Neumann, etc.) haven’t really talked about it until more recently as it has become somewhat of a catch phrase.
In short, it’s not unusual. It’s essential. Therefore it really doesn’t mean much in terms of distinguishing one high quality product from another. Consequently we sort of smile when we hear manufacturers making a big deal about this.