Vocal Recording Basics Part 2: Signal-to-Noise (SNR)

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As mentioned in Vocal Recording Basics Part 1, recording technique is more valuable than equipment. The primary tenet of a good, clean-sounding recording comes from a high signal-to-noise ratio.

Signal-to-noise is the difference between the desired recorded material (e.g., your voice) to the noise level (electrical noise, room echo, environmental noise, etc.). The less noise in the recording, the better. You can measure and define the signal-to-noise ratio in decibels, but we’ll spare the details for another post. Simply listening should be enough to determine a quality recording with high SNR. Once you learn the difference, you’ll find that a recording with poor signal-to-noise just “feels” sloppy and unprofessional. 

Recording equipment manufacturers often tout the signal-to-noise performance of their the equipment. Premium recording devices specify upwards of 110 dB SNR, A-weighted. Expect to pay a hefty price for minor (less than 5dB) improvements in signal-to-noise for professional equipment.

While high signal-to-noise ratio offer superior results in a technical sense, they’re largely irrelevant for most devices made in the last twenty years. Using proper recording practices, you only need about 60dB of SNR for a professional-sounding recording. Before digital recording came along, reel-to-reel studio master tapes were used as the standard recording format in the music industry. Artist fro Frank Sinatra, The Beatles, Pink Floyd, and Michael Jackson all recorded on reel-to-reel tapes that were then state of the art. At the very maximum, these tapes had less than 77dB of SNR. FM radio averages less than 60dB SNR, and cassettes tapes were even lower at around 50dB SNR. 

Why do professional audio manufacturers wish to sell us mic preamps and analog-to-digital converters with such high signal-to-noise ratios? The lower noise floor is advantageous for specialty recording applications, but provide little value for home studio recording. 

The Noise That Matters

Self-noise from electronics are not the cause of poor recordings, which means that your recording equipment isn’t the problem. Noise in amateur recording results from the following:

  • Room reverberation (sometimes referred to as “echo”)
  • Environmental noise (e.g., dogs barking, noisy neighbors, and computer fans)
  • Poor gain staging, or recording too quietly, then adding more gain in postproduction

If you can address those two problems, then you can create professional sounding recordings quite easily. Having a decent microphone helps, but you’d be surprised at how much a difference it makes even recording into your phone. Here’s how to deal with noise. 

  1. Get Closer

Get close to your microphone. Keep your face within five inches of the microphone at all times. As you increase your distance from the microphone, you also decrease your signal level. Get too far away, and the signal (your voice) to noise (ambient sounds) become equal. Our ears and brains cannot easily distinguish between noise and voices that are of equal loudness. You must increase the volume of your voice in the microphone relative volume of your ambient environment. 

If you get pops or “plosives” into the microphone, you can turn your head slightly during “p’s” “b’s” and “t’s” or use an inexpensive pop filter. 

  1. Project

Speak as if you’re addressing an audience. I’ve lead training sessions and workshops, and the biggest mistake beginners make with recording is speaking too softly. Your voice is the signal and your ambient environment is the noise. 

Think of turning your voice up as equivalent to turning your background noise down. If you’re close to your mic and speaking loudly, your environment will be nearly inaudible. It sounds bizarre, but if you’ve never tried it, you’ll be astounded by the difference. This is why you’ll see television interviewers using handheld mics at concerts, parties, red carpet events or anywhere is full of ambient noise. Speak loudly and getting close to the microphone works wonders in even worst environments.

  1. Record in a Large Room

Contrary to popular belief, larger rooms are preferable for recording. Small sound booths are used in professional studios to acoustically isolate a singer or instrumentalist from louder instruments. In other words, sound booths act as a quiet chamber, not as an acoustically desirable environment. Many home studios set up booths incorrectly thinking that a booth has inherent recording advantages. 

The goal here is to eliminate noise in the form of room echo, or reverberation. As you speak, sound bounces off of walls and returns back into the microphone. These acoustic reflections decrease in volume with distance. Therefore, the farther you are from your walls, the lower the noise from acoustic reflections will be. Ideally, record in a large room with carpeted floors, as hard surfaces can cause acoustical reflections for any environment. 

It’s worth mentioning that there’s a tradeoff between ambient noise level and acoustic reflections. If your largest room has only hard surfaces or has a loud ambient noise level, then you’re better off with a smaller room. Recording in a living room with a blaring TV nearby or with bustling traffic outdoors will not suffice. Your quietest room is always your best option, but opt for a large quiet room over a small one. 

  1. Remove Noise Wherever Possible

This one’s a no-brainer, but you’d be surprised how many things make noise until you start recording. Remove ticking clocks, unplug any AC transformers, turn off dimmable or fluorescent lights, and get a long cable to get your microphone away from your computer’s noisy fan. Always listen before recording, and keep your ears pealed for anything that might be making noise in the background. 

Summary

Controlling your physical location, proximity to your microphone and the level of your voice, goes a long way toward making professional-sounding recordings using any equipment. Try these techniques while recording into a smartphone and notice what a difference it makes. Keep in mind that entry-level studio equipment is good enough to create a professional sounding recording, and focus on making major improvements in your technique, not your gear. 

Continued in Part 3

CEO and Founder of Finewav. Instagram: @ErykThompson Vero: @ErykThompson

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