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Plug-In Masters

Whether they favor an all hardware signal path, work entirely in the box or use some combination of the two, the majority of mastering engineers will at some point reach for a plug-in.

 iZotope RX 2 AdvancedWhether they favor an all hardware signal path, work entirely in the box or use some combination of the two, the majority of mastering engineers will at some point reach for a plug-in. So what do the mastering professionals recommend?

Especially on restoration and remastering projects, mastering engineers must contend with various types of unwanted noise, including clicks, pops, crackle, hiss, buzz and hum, as well as all manner of accidental intrusions, such as phones ringing or dogs barking. At the end of 2010, iZotope ( released the latest updates to its award-winning audio repair software suites, RX 2 and RX 2 Advanced, which are designed to repair damaged audio and deliver the best result, whether in mastering, recording or post production.

The software has been especially beneficial in orchestral recordings for Stephen Marsh, of Stephen Marsh Mastering in Hollywood, CA. “I’ve taken out chair squeaks and page flips and the conductor’s baton scraping across the stand,” he reports.

Waves Linear Phase EQFlux BitterSweet IIThe new version of RX 2 adds new Decrackle and Channel Operations modules to the original’s Denoise, Spectral Repair, Declick, Declip and Remove Hum modules. RX 2 Advanced has been enhanced with an adaptive Denoiser mode, a Deconstruct module, new re-sampling, dither and time and pitch control, and other features. Both versions are available as a suite of plug-ins or as an application.

Both versions include new visual tools, including the Magic Wand, Lasso and Brush, which are designed for selecting audio in the file’s spectrogram. “RX is wonderful. You can take a squeaking chair or a cough, and you can draw around the piece and hit delete on the sonogram,” elaborates Steve Turnidge, owner of UltraViolet Studios in Seattle, WA.

Stillwell BombardierThe tools work similarly to graphic design software; the Magic Wand, for example, can automatically select a sound and even automatically select its harmonics. The software’s Spectral Repair functionality will even fill in gaps in the recording after removing unwanted noises.

Turnidge masters wholly within the computer and will shortly publish a book on the subject through Hal Leonard, entitled, Desktop Mastering. Although he has long used Sony’s Sound Forge as his mastering workstation, he notes that RX 2 Advanced’s new ability to host thirdparty plug-ins does offer an alternative platform.

Marsh has an additional reason to be enthusiastic about RX: “The impressive part is how quickly I was able to learn how to use it, and get relatively skilled at it, and how fast it operates. It really does make me a better engineer.”

Ron Boustead, who has established Resolution Mastering in the guesthouse of his Los Angeles area house, utilizes something of a hybrid workflow that combines a few choice pieces of analog hardware with Apple’s Logic ( platform. According to Boustead, “Some of the [Logic] plug-ins are perfectly fine for adding level, particularly the Limiter, which has a look-ahead feature; I use the Limiter fairly often. I use the Multipressor occasionally, and if I’m in the digital realm and I need a touch of EQ, I’ll use the Equalizer. The Linear Phase Equalizer is pretty good, too.”

Among his current favorites, says Boustead, “Lately, I’ve been into the Waves Renaissance DeEsser. I find it very useful and easy to see when you’re manipulating sibilance.”

Indeed, a variety of Waves Audio ( plug-ins gets the thumbs-up from all three engineers. The company has developed numerous plug-ins with applications in the mastering process, gathering together the most useful software into its Masters bundle.

Marsh singles out the Waves Linear Phase EQ for particular praise. “Occasionally, I’ll get score material that was 5.1, and they never did anything other than fold it down and hit record on the 2-track for the stereo version. So you get 5.1 channels of rumble, and you’ve got to do some filtering. There’s nothing as effective at grabbing the fundamental and a couple of harmonics and taking the energy level down, so it’s more like a bass room tone.”

With the exception of a Sony noise-reduction plug-in, Turnidge uses only Waves plug-ins in his signal chain, including the S1 stereo imager, C4 multiband parametric processor and the L3 UltraMaximizer. “The C4 is the heart and soul of my mastering chain,” he comments.

“The secret is to make the file as neutral as possible before giving it to the UltraMaximizer,” he adds. “That’s what all the previous plug-ins [in the chain] are about. Then, with this plug-in, the neutral file becomes beautiful and large.”

Turnidge also recommends Har-Bal (, from the company of the same name. “Craig Anderton uses this as his first stage in mastering,” he reports

The harmonic balancer is a standalone application described by the company as “an FIR digital EQ designed expressly for mastering, with a musician-friendly interface.”

It can be difficult to judge between two files if one has, say, 6 dB of boost applied through compression in a certain frequency range, as the louder file will invariably sound better to most ears. Har-Bal combines spectrum analysis with linear phase digital filtering, also applying essential loudness compensation as the spectral balance is adjusted.

Boustead has a few other recommendations: “There’s a plug-in called The Glue made by Cytomic. At your final stage, it does what it sounds like it would do; it’s basically a compressor that is pretty effective and transparent.”

Introduced in late 2010 and modeled on the revered SSL 4000 Series bus compressor, The Glue’s ( algorithm instead incorporates the performance of an ideal VCA for a sound quality that is closer to the XLogic G Series compressor. Going beyond the functionality of that original ‘80s console circuit, The Glue includes an ultra-fast attack time of up to 0.01mS, plus a Range knob. External side-chain support and an adjustable side-chain high-pass filter are also included.

Less well known, perhaps, are BitterSweet II and a Stereo Tool from French developer Flux (, which Boustead also recommends. Both are available for free download.

BitterSweet is a transient designer that features one large knob that ranges from Sweet (less transient amplitude) to Bitter (maximum amplitude). It incorporates an MS matrix, allowing processing to be applied only to the mid or side (stereo), as well as the center. It supports up to eight channels, although Center and Stereo mode are supported only in 2-channel operation.

The stereo tool offers a permanent vectorscope display with PPM meters and a phase-correlation meter, with individual control of left and right channel gain and pan, as well as phase inversion.

Last, but not least, Boustead recommends Bombardier from Stillwell Audio ( Designed for both mixing and mastering, the bus compression plug-in introduces an interesting mode for the latter known as Bomb. This mode applies almost instantaneous attack and release settings yet with smooth gain reduction. In order to preserve transparency when compressing a full mix, five pre-emphasis filter modes vary Bombardier’s response to the frequency spectrum.