The Pursuit of Clean Tracks - EMusician

The Pursuit of Clean Tracks

Last year, I had the pleasure of recording Julie Day’s debut album (www.julieday.org). Julie wanted the sound of a small jazz combo playing in a small, intimate environment. Most tracks were recorded live, with drums, upright bass, rhythm guitar, and piano, usually recorded simultaneously, along with a scratch vocal. Lead vocals and some solos were the main overdubs.
Author:
Publish date:

Due to the relatively sparse arrangements, any noise on individual tracks would definitely stick out, so keeping things clean was a priority. Here are some of the steps we took to make sure we had truly “sanitized” tracks. (Also refer to my column in the August issue, “You Want Good Sound? Go to the Source,” which deals with getting good sounds before you even hit the record button.)

BE QUIET!

Isolation from outside noise is crucial: While you may be able to edit out some noises, that’s not always possible, and rarely ideal. If your regular room suffers from outside noise problems, try to record during quiet times, move the essential gear to an alternate location for the tracking, or rent time in a different studio for recording really quiet tracks. Some other tips:

n Don’t overlook noise sources and issues inside the room. Fluorescent lights and CRT monitors can cause hum or “hash” in electric guitar and bass pickups, and transformers can induce hum. But there are also some trickier issues. For example, in a post-production situation, video might be monitored on a standard NTSC television as a “reality check.” Yet televisions produces a fairly loud signal at 15.734kHz (NTSC) or 15,625kHz (PAL or SECAM), so doing that little “fix-up” narration in the control room might well record the horizontal oscillator sound as well. The “sledgehammer” solution is a steep notch filter, but the easiest solution to a variety of problems is an LCD monitor, which doesn’t emit the same kind of radiation (and also uses less electricity and gives off less heat).

n Avoid ground loops when connecting your equipment. Create some cables with the shield disconnected at one end only, mark them carefully, and patch them in one at a time to check if the “broken ground” can interrupt a ground loop (but never try to stop a ground loop by lifting the ground pin on an AC cord).

Use high-quality AC line filters and conditioners (e.g., from Furman, Equi=Tech, etc.) to reduce EMI and RFI noise that can come in over the electrical lines. If you measure the before-and-after noise of some pieces of gear, you’ll find this can cut noise by several dB.

n Consider using close-miking techniques to achieve a higher sound source-to-noise ratio. The further the mic is from the sound source, the more preamp gain you’ll need to get decent levels into your DAW. But also remember mic placement is always subservient to musical considerations. Because Julie’s CD was a jazz project, I used the more overhead mikes as the drum sound’s foundation (although I did fill them out with a bit of judicious close miking).

n Although you can bypass mic and preamp noise altogether with many instruments by recording direct, make sure you can afford to give up the “air” that recording from an acoustic sound source or amp delivers.

n Experiment with your keyboard’s volume level, as most output controls have a place where they produce the best balance of strong signal and low noise — usually in the upper 20 percent of their range.

ALL THE GAIN’S A STAGE

Optimizing levels at each stage of the signal chain is vital. Too little signal at the start of the chain will require too much gain later on in order to get good levels to your recorder, which means added noise. Any self-noise that is present in the mics will be amplified and accentuated by the preamps, and especially by compression, as compression brings up the relative volume of any low level noise. The more of anything you put in the signal path, the more noise you’ll hear. Less is more (and noise is cumulative), so unless there is a good sonic reason to stick something into the signal path — don’t.

With Julie’s voice, I used a Soundelux ELUX 251, Vintech Dual 72 pre, and a touch of Aphex 106 compression when tracking. We didn’t need EQ going in, so we didn’t use any. As we were going for a close and intimate sound, Julie used a soft and breathy voice, and I placed the mic in really close to capture the detail and intimacy we sought. Julie knows how to work a mic — leaning in closer for quieter passages, and pulling back a bit when letting it rip, which helps a great deal. If only all singers knew good mic technique, engineers (and gear) wouldn’t have to work so hard.

The compression wasn’t slammed; on average I kept it to 2–4dB of reduction on the peaks, and never more than 6dB. I could have done away with the compression and had a bit less noise on the vocal tracks, but the slight increase in noise from the compression was a worthwhile tradeoff to achieve a more intimate and detailed vocal where you could hear all the nuances of Julie’s singing. The goal is to be musical, so I’d rather have a musical track with a hint of noise than a completely clean track that isn’t as musical. As you all know, making a record involves thousands of tradeoffs.

Next month, we’ll cover a few more ways to “keep it clean,” with an emphasis on working in the digital domain.