# Hearing Guard Plugin Pack

Three free JSFX plugins for REAPER, designed for safer and more comfortable headphone listening.

## Plugins

### Hearing Guard v1.9

`HearingGuard.jsfx`

An A-weighted headphone level meter with NIOSH-style daily dose tracking.

What it does:

- shows an estimated `dBA` listening level
- calculates daily dose using 85 dBA / 8 hours and a 3 dB exchange rate
- uses an A-weighted measurement path
- includes pink noise calibration
- can apply a protection fade at high daily dose
- can trigger break cues at dose intervals, for example every 20%
- includes short auto-target actions for setting digital trim

Important:

This is not a certified sound level meter or medical device. Accuracy depends on proper calibration with an SPL meter.

![Hearing Guard screenshot](screenshots/hearing-guard-v19-real.png)

### Loudness Contour

`LoudnessContour.jsfx`

A small equal-loudness / Fletcher-Munson inspired contour plugin for lower-level listening.

What it does:

- adds subtle low and high contour at lower listening levels
- helps quieter listening feel fuller
- includes a `Match levels` action that measures for 5 seconds and sets internal output compensation
- should be placed before Hearing Guard

![Loudness Contour screenshot](screenshots/loudness-contour-real.png)

### Headphone Crossfeed

`HeadphoneCrossfeed.jsfx`

A simple headphone crossfeed plugin.

What it does:

- sends a small delayed and low-pass filtered amount of left into right and right into left
- makes hard-panned stereo less extreme on headphones
- can make headphone listening feel a little more natural and less “inside the head”
- should be placed before Hearing Guard

![Headphone Crossfeed screenshot](screenshots/headphone-crossfeed-real.png)

## Recommended Plugin Order

Use this order on your Monitoring FX or master/headphone chain:

```text
Loudness Contour
-> Headphone Crossfeed
-> Hearing Guard
```

Hearing Guard should be last, so it measures the actual signal you hear.

## Installation

See [INSTALL.md](INSTALL.md).

## Quick Calibration

For Hearing Guard:

1. Set `Manual trim` to `0 dB`.
2. Turn on `Calibrate - pink noise`.
3. Measure the headphone level with an SPL meter.
4. Enter the measured value in `Ref Level`.
5. Turn calibration off.

If Hearing Guard often needs more than about `-30 dB` of digital trim, lower your DAC/headphone amp and calibrate again.

## Disclaimer

These plugins are listening aids for a safety-aware workflow. They are not certified hearing protection, medical devices, or official sound level meters. Use your judgment and lower the volume when in doubt.