by Steve Cunningham

If you do any type of remote recording, at some point you will need a noise reduction program. Hum, buzz, air conditioner noise, general room noise — any of these will give you fits if you need to clean them using EQ or expanders or any of the other tools with which we make do. Many of today’s editors come with their own noise reduction functions or plug-ins. Some are quite good, while others... well, not so much. Then there are the third-party noise reduction plug-ins, some of which we’ve reviewed here (Waves’ Restoration Bundle and Bias’ SoundSoap Pro). The Waves bundle is particularly good, but it comes at a high price ($1200 for the native version).

iZotope have recently released their own noise-reduction program. It’s a standalone program called RX, and it lists for $349 USD, substantially below the third party plugs. What’s more, RX offers five distinct modules: a de-clipper, a de-clicker, a de-noiser, hum removal, and spectral repair, all in one interface. I’ve mentioned iZotope recently in connection with their Radius time-stretching software, which is now used in Adobe Audition 3, Pro Tools 7.4, and other editors. The programmers at iZotope seem to know what they’re doing with DSP, so let’s see how they do with some sonic nasty bits.


RX runs on both Windows and Mac computers, using Win XP, x64, or Vista, and Mac OS 10.3.9 and later (it’s a Universal Binary to boot). The application takes less than 35 MB of space, but it does all its work in RAM, so you’ll need free memory of about three times the size of your file at minimum — as always, more is better when in comes to RAM. The same goes for processor speed, since RX’s processes are computationally intensive. I performed my evaluations mainly on a 2.16 GHz MacBook Pro with 2 GB of RAM. It’s a reasonably current machine, yet some processes still took considerable time as we’ll see.

Installation is quick and easy, and I had no issues. RX is copy-protected, and you have a choice when you register the product of using a challenge/response serial number system, or of using a $40 iLok (of course if you already have one you can simply add the auth to that iLok). I chose the iLok, and I’m doing that more often than ever because I find the iLok to be convenient when working on multiple editors and multiple computers. I can move the iLok between Macs and PeeCees without having to think much, and my plugs are available wherever I’m working. In either case, the program will work as advertised during a 30-day demo period, except that saving is disabled, so you’ll have time to see if it works for you.