iZotope RX 2 Advanced review: pt. 1/3

iZotope RX 2 has been designed to be the definitive audio restoration application that runs as a standalone or as a plugin directly into your favourite DAW boasting innovative new processing technology for repairing audio that claims to deal with the following:

• Remove hum without sacrificing low‐end frequencies
• Reduce ambient hiss without compromising upper partials
• Eliminate pops and clicks leaving no audible artefacts
• Remedy distortion and even gaps in the audio recording
• Repair audible clipping with perfect precision
• Replace damaged parts with inaudible patches
• Visualise your repairs before and after processing with our revolutionary spectrogram utility
• Record and recall an unlimited number of precise presets within each module
• Use a variety of application modules in any order in virtually unlimited combinations

There are 2 versions for RX 2, a standand and the advanced one we’ve tested. This image will help you comparing the two versions (among the things to notice, the fact they added Radius in the Advanced version, a great tool!)

Now take a look at their video here to see what I am going to be discussing (this article is split in three parts, please follow the links at the bottom of each page).

In the past I have tried many different noise repairing plugins/tools and therefore what has become clear to me is that more often than not I can never get to the heart of the problem without the audio being effected greatly with the introduction of ‘watery’ artefacts that make the audio unusable. I therefore became quite excited by the possibilites Izotope had brought to the table.

Audio restoration can address problems including:

• ambient background noise
• electrically‐generated interference like buzz from fluorescent lights
• hum from bad ground connections
• background hiss from tape
• surface ticks and pops from vinyl
• overload distortion (or clipping)

iZotope RX 2 In Use
The key to successful audio restoration lies in your ability to correctly analyze the subject’s condition in the first place and Izotope even give a whole section of their manual thats discuss’s the best way to convert your recordings from Vinyl and other media and also how to get setup to restore the audio, examining the audio interface, connectors/cables and even your rooms treatment. This is very kind of them and to me it is clear that this company are indeed not only interested in analysing sonic characteristics but they understand it too. They understand that for us to analyse and understand what we are hearing, we need to see this and they do this with in a very simple but effective way by providing us with not only a comprehensive set of tools (which we shall look at) but also a spectrogram and waveform display that help you see and zero in on noise. I’m using Izotope RX 2 Advanced which extends the standard version of RX 2.

Let’s have a look at how useful the spectrogram and waveform display tools are for examining the audio first of all. The spectrogram displays the individual frequencies of the audio over time and can at first take a little getting use to. Below is an image of a simple Sinewave sweep from moving up in pitch from 60 to 12,000 Hz. It is very obvious what is happening to the pitch of the audio – it is moving up! We can see how loud events are by how bright the image is. The black background is silence, while the bright orange curve is the sine wave moving up in pitch.

Typically up to now we are used to looking at simple waveforms and that is all, this ability to see the sound via a spectrogram really is fantastic and is the key to allowing us to see our sound much more clearly and precisely. Looking at something more complex such as the human voice shows just how useful this is.

Here is a short spoken phrase as seen in RX’s waveform view:

Let’s look at the same audio in the Spectrogram so you can now see that the human voice is much more complex than it might seem from looking at the waveform view. Each word is made up of a fundamental frequency (at the bottom of the spectrogram) harmonics that extend above that frequency, sibilance (“S” sounds) that begin or end words, and more, plus, you can now more clearly see the noise that is surrounding the voice.

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