Alder Audio’s debut mic is at once innovative, classy and highly affordable.
In many ways, the ribbon microphone is the quintessential ‘boutique’ product. It’s a fundamentally simple design that is nevertherless amenable to endless modifications and improvements, and the all‑important process of fitting and tensioning the ribbon can’t easily be done other than using skilled human hands. With the popularity of ribbon mics showing no sign of declining, it’s no surprise that manufacturers continue to innovate.
The newest faces in this particular sphere are Alder Audio, an American manufacturer led by Tyler Campbell, and their launch product is a passive ribbon microphone called the H44. This uses a ribbon motor design that has several interesting features. Like most ribbon mics, its pickup pattern is natively figure‑8, but it’s designed in such a way that the front and rear of the mic have intentionally different frequency responses. (If that’s not what you want, Alder also make the symmetrical H44S.) The most interesting development, however, and the one for which Alder Audio have been granted a patent, concerns the ribbon itself.
The functional principle of a ribbon mic is simple: a very thin, lightweight strip of metal foil is suspended between the poles of a magnet. When sound incident from outside causes this strip to vibrate, electromagnetic induction generates a tiny alternating current, which is then passed to a step‑up transformer to generate a more workable output voltage.
The ribbon itself is usually made of aluminium or an aluminium alloy, and for a number of reasons, it needs to be corrugated. This makes it easier to tension the ribbon correctly, increases its effective length and hence increases the sensitivity, and most of all, helps to make it more elastic and thus more durable. A strip of foil 2 microns or so thick is inherently fragile, and if it were simply stretched flat within the frame, the slightest air movement would be enough to break it.
Alder Audio’s key innovation is a new pattern which they refer to as...