k2k audio Stencils for sound. Draw boundaries around exactly which frequencies, amplitudes, or time regions you want to affect — everything else stays untouched.
Frequency Band Mask
What it does Isolates a band of frequencies and splits the signal into what falls inside the band and what falls outside.
When you’d reach for it You want to work on just the mids, or carve out a bass region to process separately, without touching anything above or below.
Quick example
- Connect your audio source to the input.
- Set Low Hz to 200 and High Hz to 2000 to grab the midrange.
- Bump Feather to 50 Hz for a gentle rolloff at the edges instead of a hard cut.
- Route the Masked output to your processing chain, and the Rejected output to a mixer so you can blend them back later.
Parameters
| Parameter | What it controls | Range | Sweet spot hint |
|---|---|---|---|
| Low Hz | Bottom edge of the frequency band | 20 — 24 000 Hz | Match the lowest note of the region you’re targeting |
| High Hz | Top edge of the frequency band | 20 — 24 000 Hz | Match the highest note of the region you’re targeting |
| Feather | How gradually the edges fade in and out | 0 — 500 Hz | 30—80 Hz avoids ringing at the boundaries |
| Invert | Swaps which output gets the selected vs. rejected content | On / Off | Turn on when you want to process everything except the band |
Amplitude Mask
What it does Selects spectral content that falls within a loudness range and splits it from everything quieter or louder.
When you’d reach for it You need to treat the quiet residual hiss differently from the loud foreground, or you want to grab only the peaks of a signal and sculpt them on their own.
Quick example
- Connect your audio source to the input.
- Set A.Min to -40 dB and leave A.Max at 0 dB to grab everything above -40 dB.
- The Masked output now carries the louder content; the Rejected output carries the quiet stuff below -40 dB.
- Add Feather at 6 dB if the split sounds too abrupt.
Parameters
| Parameter | What it controls | Range | Sweet spot hint |
|---|---|---|---|
| A.Min | Lowest amplitude included in the selection | -96 — 0 dB | Start around -60 dB and raise until you hear the split |
| A.Max | Highest amplitude included in the selection | -96 — 0 dB | Usually stays at 0 dB unless you want to exclude the loudest peaks |
| Feather | Softness of the amplitude boundary | 0 — 20 dB | 3—6 dB keeps transitions smooth without smearing |
| Invert | Swaps which output gets the selected vs. rejected content | On / Off | Turn on to process the quiet content instead of the loud |
Unified Mask
What it does Selects spectral content that meets frequency, time, and amplitude criteria all at once.
When you’d reach for it You have a specific moment in a specific frequency range at a specific loudness that needs attention — like a resonance that only appears in the mids during the chorus, or a click at 0.5 seconds in the low end.
Quick example
- Connect your audio source to the input.
- Under Frequency Hz, set Min to 800 and Max to 3000.
- Under Time s, set Min to 2.0 and Max to 4.5 to target just the chorus.
- Under Amplitude dB, raise Min to -30 dB so only the louder content in that region is selected.
- Turn on Trim if you want the Masked output shortened to just the selected time window.
Parameters
| Parameter | What it controls | Range | Sweet spot hint |
|---|---|---|---|
| Min (Frequency) | Bottom edge of the frequency band | 20 — 24 000 Hz | Narrow the range to the region that matters |
| Max (Frequency) | Top edge of the frequency band | 20 — 24 000 Hz | Keep some headroom above your target |
| Feather (Frequency) | Softness of the frequency edges | 0 — 500 Hz | 30—80 Hz for musical transitions |
| Min (Amplitude) | Lowest amplitude included | -96 — 0 dB | Raise to exclude background noise from the selection |
| Max (Amplitude) | Highest amplitude included | -96 — 0 dB | Lower to exclude the loudest transients |
| Feather (Amplitude) | Softness of the amplitude boundary | 0 — 20 dB | 3—6 dB for clean crossfades |
| Min (Time) | Start of the time window | 0 — duration s | Scrub playback to find the exact moment |
| Max (Time) | End of the time window | 0 — duration s | Give yourself a small margin on either side |
| Feather (Time) | Softness of the time window edges | 0 — 50 frames | A few frames smooths clicks at the boundary |
| Invert | Swaps which output gets the selected vs. rejected content | On / Off | Turn on to process everything outside your selection |
| Trim | Shortens the Masked output to only the selected time range | On / Off | Useful when you plan to export or re-layer just the slice |