As the sound reaches both mics at slightly different times, the resulting interference creates frequency peaks and troughs that wreak havoc on the recorded dialogue.
This is often the result of signals from separate boom and lavalier mics being collapsed into a single channel, rather than split to separate tracks. More of a challenge is one of the more frustrating issues that can arise when working with location dialogue recording: comb filtering. It takes very little time for Unfilter to analyse the problem and apply corrective equalisation to bring the signals back to life. Simple examples of corrections that Unfilter can make include compensating for overzealous high– or low–pass filtering that has removed too much bass or dulled the top end of a signal. The controls in the Process section determine the degree to which this function is applied. In order to remove the applied filtering, Unfilter then creates a transfer function, which can be thought of as a ‘mapping’ of the frequencies that need to be manipulated in order to restore the signal to a more desirable state. It accomplishes this with what Zynaptiq call “real–time blind de–convolution” to analyse the signal and guess at what was done to it. I Can See Clearly NowĪt its heart, Unfilter is designed to estimate the frequency response of a filter that has been applied to a piece of audio, then apply a complementary filter to reverse its effects. To put Unfilter and Unchirp to the test, I assembled some pretty difficult test material to find out if they live up to Zynaptiq’s claims.
For sound–design applications with Unfilter it’s possible to use a mouse (or better yet your finger on a Slate Raven) to employ a real–time resonance filter during playback. Herein lies the power of these plug–ins, and their potential for creative sound design applications: in Unchirp, these nodes allow you to adjust the threshold and frequency amounts independently, offering greater control and flexibility. There are a number of curve types that connect the nodes in either linear or smooth transitions or stepped edges and peaks/dips. Zynaptiq’s Unfilter can correct not only broadband tonal imbalances, but comb filtering too.Each display offers a Breakpoint Editor, which allow you to enter a number of points to either influence the intensity of the processing in certain frequency ranges, or serve as a dedicated EQ. This colour scheme allows input and output data to be displayed simultaneously without feeling too cluttered to view. Both plug–ins sport a graphical display that provide live visual feedback of both frequency and amplitude of input (in magenta) and output signals (for Unfilter) or clean components (for Unchirp) in mint green. I really like these: they’re not just easy to use with a mouse, but are fun to use on a multi–touch display, and make it very easy to see at a glance what your settings are. They function as vertical faders, and have a horizontal line along with a colour–coded border that accompany movement. The graphical interfaces of both processors feature the unique spherical controls, referred to as Trackball Sliders, that are found on other Zynaptiq plug–ins. None of these tasks are easy to accomplish using conventional processors. Unchirp is designed to remove artifacts that arise from broadband noise reduction and lossy audio encoding, and can also restore transients lost or smeared as a result of over–compression. Unfilter promises to help remove comb filtering in dialogue recording, as well as providing easy–to–use, intelligent corrective equalisation.
Following the release of their de–reverberation software Unveil (reviewed in SOS July 2013: Zynaptiq continue to upend the status quo with another pair of interesting utility plug–ins that not only offer a unique approach to conventional signal processing, but also tackle problems that previously were considered nearly impossible to solve. Zynaptiq are one such, and have carved out a niche for themselves by focusing on innovative digital processes that have yet to be realised by mainstream developers. Innovation doesn’t come easy, and sometimes requires bold steps from small companies who have fresh ideas and a willingness to think different. Zynaptiq’s innovative processors are claimed to address previously intractable problems with recorded audio.