Tune NR4 masking depth and suppression strength¶
The NR4 engine's Masking Depth: and Suppression: sliders give you fine-grained control over how aggressively spectral masking is applied and how strongly noise is suppressed overall. Adjust these two parameters together to balance noise reduction against speech clarity.
Before you start¶
- Open AetherSDR and enable NR4 on the receiver you want to adjust.
- Have a signal or noise source active so you can hear the effect of changes in real time.
Steps¶
- Click
Settings > AetherDSP Settings.... - Click the NR4 tab.
- Locate the Masking Depth: slider. Drag it left to reduce spectral masking or right to increase it. The default is 0.50; the valid range is 0.00–1.00.
- Locate the Suppression: slider directly below. Drag it left to reduce overall suppression or right to increase it. The default is 0.50; the valid range is 0.00–1.00.
- Listen to the result. If speech sounds over-processed or hollow, reduce one or both sliders. If residual noise is too audible, increase them.
- To undo all NR4 changes at once, click Reset Defaults. This restores Masking Depth: to 0.50 and Suppression: to 0.50, along with the other NR4 defaults.
What each control does¶
| Control | Default | Range | Persisted key | Behavior |
|---|---|---|---|---|
| Masking Depth: | 0.50 | 0.00–1.00 | NR4MaskingDepth |
Controls how deeply spectral masking is applied to noise bins. Higher values suppress more noise but can affect tonal quality. |
| Suppression: | 0.50 | 0.00–1.00 | NR4SuppressionStrength |
Sets the overall NR4 suppression strength. Higher values produce more aggressive noise reduction across the spectrum. |
Tips¶
- Masking Depth: and Suppression: interact: raising both together produces maximum noise reduction but the highest risk of speech distortion. Raise them incrementally and test on a live or recorded signal.
- If you also have Reduction (dB): set high, lowering Suppression: slightly can recover naturalness without losing much noise floor reduction.
- The Adaptive Noise Estimation checkbox affects how quickly NR4 tracks a changing noise floor, which in turn affects how both sliders sound in practice. See Enable or disable NR4 adaptive noise estimation.
- Click Reset Defaults to return all NR4 parameters — not just these two sliders — to their factory values before experimenting again.
Troubleshooting¶
- Speech sounds hollow or underwater after raising the sliders — Both sliders at high values can over-suppress spectral components that overlap with speech. Reduce Masking Depth: first, then Suppression: until naturalness returns.
- Noise floor is still audible even at maximum settings — Ensure Adaptive Noise Estimation is enabled so NR4 can continuously re-estimate the noise floor. Also consider increasing Reduction (dB): via Adjust NR4 reduction amount in dB.
- Slider snaps back or refuses to move — In v0.9.7 the dialog content was moved into an embedded
AetherDspWidget. Click directly on the slider handle rather than clicking in the groove; the guarded input model is unchanged.