How quiet is the Orfield Laboratories anechoic chamber?

What the numbers mean

How it was measured. Ambient (background) sound level inside the anechoic test chamber at Orfield Laboratories, Minneapolis, measured for Guinness World Records on 19 November 2021.

An anechoic chamber absorbs sound instead of reflecting it, and a good one is also isolated from noise outside. The figure Guinness records is the chamber's own background level, the faint residual sound present when nothing inside is making a noise. A negative decibel value simply means a sound pressure smaller than the 20 micropascal reference that defines 0 dB.

Orfield's room has held the record three times. Guinness World Records says it first took the title in 2004 with a background reading of -9.4 dBA, recorded -13 dBA in 2012 after improvements, lost the record in 2015 to an anechoic chamber at Microsoft's headquarters in Washington (-20.35 dBA), and regained it in 2021 at -24.9 dBA. Orfield Laboratories lists its three results as -9.4, -13.4 and -24.9 dB, so the two sources differ slightly on the 2012 figure.

With the outside world removed, the body becomes the loudest thing in the room. Company founder Steven Orfield told MailOnline, as quoted by Guinness, that you hear your heart beating, sometimes your lungs, and your stomach gurgling loudly.

Is it safe?

Below 85 dBA, the level NIOSH allows for a full 8-hour day. At this level, sound is not a hearing risk however long it lasts, though it can still disturb sleep or concentration.

Protecting your hearing

No hearing protection is needed: the room is far below the level of a quiet breath. People who feel uneasy in total silence can simply leave; the discomfort comes from the lack of sound, not from noise.

Earplug and earmuff ratings (NRR in the US, SNR in the UK and EU) are lab figures; real-world protection is usually lower. How to read the ratings.

Compared with sounds nearby

Using midpoints of each range. Energy multiplies by 10 every 10 dB; perceived loudness roughly doubles (why).

• Microsoft anechoic chamber (−20.6 to −20.4 dBA): it has about 2.8× the sound energy of this and sounds about 1.4× as loud.
• Haleakalā crater (10 dBA): it has about 3,090× the sound energy of this and sounds about 11.2× as loud.
• Normal conversation (55–70 dBA): conversation has about 5.5e+2 million× the energy of this.

Questions

Sources

1. Quietest place, Guinness World Records. Supports: dB_low/dB_high: -24.9 dB, 19 November 2021.In tests conducted on 19 November 2021, the ambient sound level inside the room was measured at -24.9 decibels.Checked 2026-11-02.
2. Quietest place, Guinness World Records. Supports: weighting: A.-24.9 decibel(s) (A-weighted)Checked 2026-11-02.
3. Inside quietest place on Earth where you can hear your blood pumping and eyes blinking, Guinness World Records. Supports: body: 2004 record of -9.4 dBA.The Orfield Labs room first broke the record in 2004 with a background noise reading of -9.4 dBA.Checked 2026-11-02.
4. Inside quietest place on Earth where you can hear your blood pumping and eyes blinking, Guinness World Records. Supports: body: 2012 figure of -13 dBA.Even lower sound levels of -13 dBA were recorded there in 2012 after some improvementsChecked 2026-11-02.
5. Inside quietest place on Earth where you can hear your blood pumping and eyes blinking, Guinness World Records. Supports: body: what visitors hear.You'll hear your heart beating, sometimes you can hear your lungs, hear your stomach gurgling loudly.Checked 2026-11-02.
6. "The Quietest Place on Earth", Orfield Laboratories. Supports: body: three records, -9.4, -13.4 and -24.9 dB.the lab submitted to Guinness for the low levels of sound recorded in the chamber (-9.4dB, -13.4dB, -24.9dB), resulting in three Guinness RecordsChecked 2026-11-02.

This page is general information, not medical advice. If you have ringing in your ears, muffled hearing or any change in your hearing, see an audiologist or your doctor.