Text: James Roche
Okay, the drums are sounding great, the guitars are all plugged and exciting, and the vocalist is back from the café. Time to record!
Fast forward to the next day, as I listened to the mega-hits-in-the-making… What’s all that noise? Where is that hiss coming from? That annoying buzz? There’s a hum in there too! And the vocalist sounds like she’s running a saliva factory – clicking and crackling through the whole take. I can’t use this!
It’s moments like these when some noise-reduction software can come to the rescue. Plug-ins and standalone apps from Waves, Sony and many others are designed to get rid of those pesky non-musical audio artefacts – and I can testify to how marvellous the results can be.
Recently I used Izotope’s RX2 noise-reduction plug-ins to help me turn a whole album’s worth of basketcase multi-tracks into noise-free bliss.
BROADBAND NOISE: DEATH BY VALVE
RX2 packs a number of task-specific plugs. The first one I needed was Denoiser, which removes broadband and tonal noise that remains largely constant throughout a recording. I had a percussion mic that, unnoticed on the day, was producing a lot of white-noise. It was the only mic on this particular instrument, a djembe, and there just wasn’t enough spill of djembe in the other mics for me to mute the noisy track. It sounded like a valve with one foot in the grave! The band didn’t play to a click, so I couldn’t easily overdub one instrument of a percussionist’s entire performance. In other words, I had no choice but to use this track.
Noise reduction plug-ins work by ‘learning’ a noise profile. If you can isolate just the noise and play that into the plug-in, the software can go to work on the rest of the track removing that noise profile from the music. At the front of this particular song before the count-in there was absolute quiet from the band so I could isolate the noise. From there I could let Denoiser weave its magic. It worked a treat, turning a crisis into salvation.
LF: SUB BASS SNARL
I might have reduced the audible noise from the dodgy valve but I could see on the spectral display of the plug-in that there was a lot of energy down in the subs, below 40Hz. I couldn’t hear it, but I could certainly see it – it was the loudest frequency band on the track! The likely culprits would be air conditioning and distant traffic.
Usually when I record, I roll off the subs on mics for anything that isn’t specifically a bass instrument or a large drum. However, I hadn’t engineered this particular session, and there was deep dark energy on every mic. Luckily, the Denoiser plug-in handled this job very well, and at the end of the processing I had clean tracks with no rumble and no wideband hiss.
GUITARS: RATTLE & HUM
Next problem – guitars! On this album we used a really old-school guitar, with noisy pickups. The recording had constant hum from both the amp and the guitar, and occasional high-frequency buzzing when the guitarist wasn’t actually touching the strings to earth the instrument.
I applied a combination approach, using the Denoiser for the buzzing and the (aptly named) Hum Removal plug-in for the constant AC noise. Hum Removal has plenty of parameters to play with but I found I was able to achieve my aims by changing the setting from 60Hz to 50Hz, to match the frequency of power in Australia. Like magic, the hum disappeared! I was beginning to love this software. It was saving my bacon.
VOCALS: SPRAYING IT
Time to deal with the vocals. They sounded pretty clean with no real noise or hum problems – but that saliva! It’s in the singing; it’s in the breathing – it’s everywhere! Click, crackle, splurt!
I usually zoom right in and redraw the waveform to get rid of a random click – but this was just too large a task for all this crackling. I needed another solution. I turned to the RX2’s Declicker and Decrackler. Their job is to remove very brief audio artefacts that aren’t like anything else around them. This is more difficult in a vocal where there are desirable sibilants and transients right alongside undesirable clicks. Saying that, I found that with a bit of careful massage I could remove 90% of the saliva problems by using the software, which was a major time-saver.
On another track I also found a use for the Declipper plug-in, which turned a number of moments of slightly distorted vocal back into something useable.
PAID FOR WITHIN A WEEK
This was the first time I’d ever needed so much noise reduction and restoration processing on an album, but I reckon I’ll never leave home without it! It saved me time, and saved the project money by avoiding re-recording. It paid for itself in the first week, and it isn’t often you can say that about a purchase.
Mixing the album was now a pleasure, as I could turn everything way up, get it all forward and present, and the end result was very intimate and up-close. There is no way I could have achieved that result with the noise in there. ‘Keep it clean’ is my new motto!
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