Accuton BD30-6-036 Diamond Tweeter

The Accuton BD30-6-036 is a diamond dome tweeter intended for loudspeaker designs where the high frequency section is expected to disappear rather than to draw attention to itself. It belongs to Accuton's diamond range, in which the dome material is chosen for its extreme stiffness-to-mass ratio rather than for cost or ease of manufacture.

The design work around a driver of this quality is worth doing properly, because a diamond dome exposes crossover errors that a softer tweeter would have masked. The first decision is the crossover frequency. Diamond domes are light and stiff, which is exactly what makes them fast, but it also means there is very little mechanical damping to absorb low frequency energy that a shallow filter allows through. A steeper slope of 18 or 24 dB per octave, set at or above the manufacturer's stated minimum, is the safe and the better sounding choice.

The second decision is level matching. High quality tweeters are frequently more sensitive than the bass or midrange driver they are paired with, and the difference has to be removed with a series resistor or a proper L-pad. Doing this by ear is a false economy: measure the summed response on the finished baffle, because baffle step and diffraction move the balance by several decibels regardless of what the individual driver data sheets say.

Finally, treat the physical mounting with the same care. Recess the flange flush with the baffle, keep sharp edges away from the dome, and align the acoustic centres of tweeter and midrange, either by stepping the baffle or by correcting the delay electronically.