How to get your noise floor under -60 dB

Your noise floor is how loud your recording is when you aren’t talking. ACX, Spotify and Penguin Random House all draw the same line: −60 dB or lower. That’s quiet, but it isn’t silence. Think of a very quiet room, recorded with a mic that’s set up well.

What it’s actually measuring

The check finds the quietest stretch of your file, usually the pauses between sentences or the room tone at either end, and measures its average level. If even the quietest part is louder than −60 dB, the file fails. (Narration Studio ’27 looks at the quietest half second.)

So what matters is how quiet your pauses are. A loud breath or a mouth click usually won’t sink you here. The steady sound sitting under everything will: hiss, hum, fans, traffic.

Figure out where it’s coming from

Record ten seconds of nothing and listen back on headphones with the volume way up. What you hear tells you what to go fix.

• A steady hiss is usually electronic. The mic, the preamp, or the gain turned way up to make up for sitting too far back.
• A low hum or buzz is usually electrical: a ground loop, a cable lying next to a power supply, a dimmer switch. Hum lives at 50 or 60 Hz and the multiples above it.
• A rumble or a whoosh is the room. Fan, heat, air conditioning, the fridge in the next room, traffic, the computer.
• A hollow, roomy sound on your voice isn’t noise floor at all, it’s echo. It does make noise reduction work a lot harder, though.

Fix it at the source first

The biggest win for most home studios is getting closer to the mic and turning the gain down. Every time you halve the distance, your voice gets about 6 dB louder while the room stays exactly the same, so you can drop the gain and the noise drops with it. A hand’s width, four to six inches, is a good place to start.

Then turn stuff off. Fans, heat, air conditioning, the fridge if you can hear it, chargers that buzz. Get the computer away from the mic, or put something between them.

Point the mic away from the noise. Most narration mics hear the least out of their back side, so aim that at the window, the door or the computer.

Soften the room. Blankets, a closet full of clothes, acoustic panels behind and around you. That cuts echo and a bit of the outside noise too.

And if it’s hum, go after it electrically. Plug the computer and the audio interface into the same power strip, keep audio cables away from power cables, and try a different USB port.

Then clean up, gently

Noise reduction and a noise gate can handle what’s left, but both cost you something if you push them.

Noise reduction learns your room from room tone and turns it down. A moderate amount, nobody can hear it. A lot of it, and your voice starts sounding watery or metallic, which is exactly the kind of thing ACX’s reviewers listen for. Record good room tone so it has something accurate to learn from.

A gate pulls the pauses down further. Too aggressive, and you can hear the room cutting in and out around every word.

And don’t go all the way to digital silence. A pause with zero sound in it sounds like a dropout. Penguin Random House even sets a lowest limit, so the pauses keep some room tone: Narration Studio’s PRH preset holds the noise floor between −80 and −60 dB.

Check before you upload

Measure every finished file, not just the first one. The noise floor changes from session to session. A hot day with the AC running can fail where yesterday passed just fine. If one chapter fails and the rest pass, think about what was different that day.