EarEqual
Setup & measurement

Setting up the EarEqual Plug

How to connect the Plug and take a measurement. Read the safety warning below before you plug anything in for the first time.

Read this first

Never connect the Plug to 48 V phantom power

The Plug uses electret microphones that run on standard plug-in power (the low voltage on a normal microphone input). Phantom power (+48 V, the kind on XLR interfaces) will permanently destroy the microphones.

Do not connect the Plug to an audio interface with phantom power switched on, even briefly. When in doubt, use a recorder or phone adapter with a normal mic input, not an XLR interface.

01

What you need

The Plug is a measurement microphone, not a headset. To use it you need an input that supplies plug-in power. The primary setup is a device with a true stereo mic input, which captures both ears at once.

  • A handheld recorder with a stereo plug-in-power mic input (for example a Zoom or Tascam) is the sweet spot, and the recommended way to use the Plug.
  • A phone or computer also works, but its single mic input is mono, so you measure one ear at a time via the mono path below. Mac and Android are confirmed to supply the bias voltage the microphones need.
  • Avoid XLR audio interfaces (Focusrite and similar). These use phantom power, not plug-in power — see the warning above.
02

How the Plug is wired

The Plug ends in a single 3.5 mm TRS connector carrying two independent microphone lines — one for each ear — plus a shared ground. This is why it doubles as a binaural rig.

Tip
Left microphone
Ring
Right microphone
Sleeve
Shared ground

Adapters are standard, off-the-shelf parts and are not supplied with the Plug. Which one you need depends on whether your device has a stereo mic input or a single (mono / headset-style) input — see the two paths below.

03

Two ways to connect

Stereo path

Two independent mic inputs

Feed the TRS into a device with two microphone inputs (a stereo recorder). The tip and ring stay separate, so you get both ears captured independently at once. This works for headphones, loudspeakers, and binaural recording.

Mono path

A single (headset-style) mic input

A standard headset-style adapter (a TRRS splitter or USB dongle) combines both microphone lines into one mono signal, and gives you audio out plus a single mic in. In that case you drive one ear at a time, so only that side carries signal, and you measure each ear in turn.

Note: combining both capsules onto one line adds noise from the idle microphone. For frequency-response measurements this can be worked around. If you want the detail on this, get in touch.

04

Taking a measurement

  • Insert the Plug slowly and gently. It is designed to seat without force — never push against pain. Full safety instructions are on the insert in the box.
  • Start at a low playback level and raise it gradually. Measurements do not need high listening levels.
  • For headphones, measure one ear at a time, then apply the correction you derive for each ear to that ear.
A note on isolation

The Plug is a low-isolation measurement device, not an earplug. You may hear the room through it while measuring, and that is normal — it does not mean the Plug is not working.

05

Care & cleaning

Keep all liquid off the fabric face of the microphone. Clean by wiping with a soft cloth and a little alcohol applied to the cloth, never to the Plug.

Full instructions are in the Cleaning & Hygiene Protocol.

Questions about setup or hardware? Get in touch at hello@earequal.com.