CEDAR Audio Declickle 2 for Cambridge

The Problem:
In 1990, CEDAR invented real-time digital declicking and decrackling, demonstrating them to amazed audiences at the 89th AES Convention, held in Los Angeles that year.  However, these earliest digital declickers and decracklers suffered from a limitation; while they removed impulsive noises from the majority of material, they could damage the sounds of brass instruments, solo violins and sometimes human singing.

Despite years of research, this problem remained, and all declickers based on the techniques contained in CEDAR's original research still suffer from it.

The Solution:
The Declickle™ 2 is the lastest generation declicker and decrackler module, offering better impulsive noise detector and a better interpolator than any previous declicker or decrackler. This results in superior performance across a wider range of material than ever before. Indeed, this performance is so good that, in almost all cases, it is not possible to hear that the signal was damaged prior to restoration. The Declickle™ 2 module is available as a free upgrade for all owners of the original Declickle™.

Why Declickle™ 2?
Unlike a standard declicker, Declickle™ 2 is able to detect high densities of low amplitude, short duration disturbances within the signal.  A standard click-detection algorithm will miss smaller impulses, and it will fail to cope with the high density of those impulses.

However, removing each of these unwanted impulses using a basic interpolator is not satisfactory because of their fundamental nature.  Standard algorithms assume that a click or scratch has totally corrupted the audio and that there is no useful information about the signal during the click.  Since the disruptions that cause crackle are very small they may be considered to be additive, and this assumption is no longer appropriate.  Declicking a crackly signal discards a lot of useful information that an optimal algorithm can use to improve the quality of the processed audio.

Despite the power of Declickle™ 2, its user-interface is extremely simple and quick to use, and is suitable for users with limited audio engineering experience.