Review: iZotope Neutron
Need an assistant? Help is on the way with iZotope’s intelligent mixing plug-in.
Being the control freak I am, when algorithmic plug-in wannabes try to take the reins of my mix with their so-called ‘intelligence’, I typically bow out with a polite, ‘thanks, but no thanks.’ When iZotope debuted Neutron with the bold claim it would be your ‘personal mixing assistant’ I was naturally skeptical.
After using the plug-in for a few weeks now, let me say upfront: Neutron won’t mix your song for you… and that’s a good thing.
iZotope’s marketing may allude to the auto-mixing paradigm, but the real purpose behind Neutron’s artificial intelligence is to simply ‘assist’ by alerting you of potential pitfalls in your mix’s frequency balance and optimising each track to make it more mixable. While that sounds more tolerable than a plug-in getting its digital mitts all over the faders, I still approached the plug-in with suspicion. Would it be another one of those algorithmic mastering duds?
Neutron’s brain has two main assistive components; Track Assistant and Masking Meter. iZotope says Neutron’s Track Assistant “acts like an assistant engineer getting you to an optimal starting point so you can start mixing creatively.” Chris Lord-Alge eat your heart out! In use, the spirit of Track Assistant is to iron out wrinkles in a track, not to assume artistic license. You can choose between Subtle, Medium and Aggressive modes which affect the intensity of the created settings. Three more options — Broadband Clarity, Warm and Open, and Upfront Midrange — alter the flavour of Track Assistant’s settings. Overall, I thought it produced the most usable results in Subtle mode.
What could be seen as an oversight is that Track Assistant doesn’t process your track from a whole mix perspective — it only bases processing decisions upon hearing a track in isolation. More often than not you EQ an instrument very differently in solo than in the context of a mix. It does a respectable job, though the logical next step would be to have enough CPU power for the algorithm to weight up each track in the context of the entire mix.
Masking Meter is a bit closer to that ideal. It only kicks in if you have Neutron instantiated on more than one track in your session; say the guitar and keyboard buses. By clicking the Masking button in the EQ processor on either track, you select which of the other Neutron-loaded tracks you’re wanting to ‘investigate’ — in this case, let’s say guitars. The GUI changes to show two EQ curves, one for each track, and grey shaded areas appear to display where frequency collisions are occurring as the track plays. Naturally guitars and keyboards will occupy much of the same portion of the spectrum, so where these collisions are ‘problematic’, a little red exclamation mark appears. You can then carve out some space on either track’s EQ curve within the single Neutron instance. If you change the curve of the instrument not associated with the current track, it will automatically update the EQ curve on that channel’s Neutron instance.
To be honest, I found this a tad gimmicky. It’s not much help if you’re comfortable mixing with your ears. It seems Masking Meter is primarily targeted to those who are a bit newer to mixing and might not be familiar enough with what different frequency ranges sound like to create space in a mix themselves. Still, the feature is well implemented and easy to use.
NEED TO KNOW
Assistive Channel Strip Plug-In
Neutron’s EQ is clean and musical. iZotope sure hasn’t skimped — you get eight fully parametric bands, plus a shelving EQ and filter at each end of the spectrum. The EQ is equally at home surgically correcting tracks or enhancing with broad-Q curves.
Each band can be static or dynamic. Using the EQ in dynamic mode means each node respond to its own frequency point, or another node (think sidechain equalisation). This is useful in specific scenarios where you want the amount of EQ applied to a frequency to punch harder when there’s more going on in that frequency range: for example, a piano that sounds too rumbly only when the low notes are played loudly. Compress or Expand options let you select whether the EQ node boosts or attenuates when source material exceeds a variable threshold. Call me old-school but static EQ curves will keep me happy for the most part. But again, it’s a very musical-sounding EQ that’ll rival many other third-party plugs you may have.
We all know the adage ‘mix with your ears, not your eyes’, so I’m generally wary of flamboyant visual readouts while mixing. Having said that, the GUI iZotope has employed for Neutron’s two compressors is slightly addictive. Gain reduction is graphed in real-time so a quick glance shows you not only how hard the compressor is working, but how often. If your source material is something percussive like drums or acoustic guitar, the drawing looks a lot like a heartbeat on a life-support machine. Attack and release times are easy to read as well. Faster settings result in a spikier graph and vice versa. Say you’re wanting to lop off only the loudest transients on a pair of overheads — this kind of GUI makes it super easy to dial in visually.
The compressors have both Modern and Vintage settings, and the graph display is only shown when Modern is selected (needle-style meters for Vintage). Like the Transient Shaper, you can use it in multiband mode (three bands), or as a single processor. Slower, smoother settings seemed to bring out the best in Neutron’s compressor modules. A little grainy break-up was introduced when pushed hard with quick attack/release times and low thresholds. Overall the compressors have a gluey character and love sitting on mix buses and stems. Both compressor modules have a Mix slider so you can easily add parallel compression.
Neutron’s Transient Shaper is a delightful little tool that’s, in my opinion, the highlight of the channel strip. You get the option to split the source signal into three frequency bands and apply very individual treatment to each. There are three settings to determine how the plug-in alters the audio — Precise, Balanced and Loose. Furthermore, each band offers Sharp, Medium and Smooth settings, and the ability to increase or decrease Attack and Sustain material accordingly.
Don’t expect ‘point-and-shoot’ results with the Transient Shaper. Instead, imagine how you want your track to sound, consider what needs to change in the lows, mids and highs to get there, and tweak as necessary. I was mixing a song with an acoustic guitar track that sounded nice and clean in solo, but flat and lifeless in the mix. By increasing the Attack in the high band on the Sharp setting, the track instantly perked up. To keep it supported and full, I turned up the sustain in the low and mid bands using the Smooth setting. It worked a treat. Conservative settings brought about more natural results, but in busy mixes you can get away with heavy-handedness.
The Exciter shares a lot with the Transient Shaper: it has the same three global modes; Precise, Balanced and Loose; and also splits into three bands if you choose. On top of these, each band has an X/Y pad where you can dial in your harmonic distortion flavour of choice, from Warm to Tape to Retro to Tube. When split into frequency bands, the Exciter becomes a neat tool that can liven up a track with very little effort.
iZotope released Neutrino as a freebie not long before the grand unveiling of Neutron. Spectral shaping applies low-ratio dynamic processing to different portions of each track’s frequency spectrum to create a more focused, clear mix when Neutron is inserted on every track in your session. Choose the type of source material it’s working on (Drums/Percussive, Vocals/Dialogue, Guitar/Instrument, Bass), and it subtly works its magic. Neutrino is featured as part of Neutron, albeit a very small part, and Track Assistant intelligently figures out which of the four settings to use. If you’re really sold on what Neutrino does to your mix, I’d recommend sticking the smaller freebie plug-in on every track as a large session full of Neutron instances will hog CPU resources.
MULTI-TOOL FOR MIXING
Neutron isn’t a mini utility plug; it’s a fat Swiss army knife. It’s probably one of the best channel strips I’ve used — and ironically, the assistive tools played little part in forming that opinion. Leaving Track Assistant aside, not only do you have a mountain of processing options within the one plug-in, but each processor sounds fantastic in its own right. I’d buy Neutron for the Transient Shaper and Exciter alone.
Speaking of which, you’ve got two options if you choose to purchase the plug-in: Neutron, or Neutron Advanced. The latter gives you each channel strip component as an individual plug-in, plus surround support up to 7.1. Neutron also comes part of iZotope’s Music Production Bundle 2.
If Nectar, Ozone, and RX have taught us anything, it’s that iZotope loves to give us whopping great, borderline-overkill plug-ins that thoroughly cover every base, and then some. Neutron is no different. Though iZotope pitches Neutron’s artificial intelligence as its main selling point, don’t let that lead you to believe it’s not a high-quality tool for audio professionals. In fact, Neutron’s sound quality and functionality is what I found most attractive. Highly recommended.