Ambience Generator (rain, wind, stream, fire, hum, drone)

What it is for

Video editors, game makers and podcasters often need background sound that loops without a click. Recordings of rain or a fireplace are often short, licensed, or have an audible seam. This tool synthesizes six ambiences from seeded noise and oscillators: rain with individual drops, gusty wind, a bubbling stream, a crackling campfire, room tone with a mechanical hum, and an evolving drone. The result is a WAV file that loops seamlessly by default.

These are synthesized impressions, not field recordings: rain here is a filtered noise bed plus hundreds of short drop sounds. For real recordings with location and licence, use Soundscape Atlas's recording search.

Worked example

We wanted light rain on a window for a 30-second loop: Rain, 30 s, 44.1 kHz stereo, intensity 0.3, 80 drops per second at full intensity, brightness 0.3, room Living room, seed window.

The summary: "Rain, 30 s seamless loop, stereo at 44100 Hz, room: Living room: RMS −20 dBFS, peak −4 dBFS, spectral centroid 1.69 kHz." The tool synthesized 993 raindrops. The loop check reported a largest jump of 0.011 at the seam, against 0.265 inside the file, so the seam is hidden among the drops. The octave bands peak between 500 Hz and 2 kHz and fall to −9.9 dB at 8 kHz, because a low brightness dulls the rain.

A second example from the tool's list makes server-room hum on 60 Hz mains: hum at 120 Hz with 10 harmonics and room tone at −18 dB. Its spectrum shows the expected lines at 120, 240, 360, 480 and 600 Hz, and the assumptions confirm "The hum fundamental was rounded to 120 Hz so it completes whole cycles in the loop."

How to read the result

• RMS and peak level: the file is normalised to the RMS level you set (−20 dBFS by default). If the peaks would clip, it is turned down and you get a warning.
• Crest factor: high for rain and fire (sharp drops and crackles), low for hum and drone (steady tones).
• Synthesized events: the number of raindrops, bubbles or crackles. It rises with intensity, density and the "bubbles or crackles" control.
• Loop seam: the largest jump between the last and the first sample, next to the largest jump inside the file. If the seam is smaller, the loop is clean.
• Parameters used (assumptions) lists only the controls that affect the chosen sound. The others are ignored.

Tips and common mistakes

• Intensity changes the character, not the loudness: stronger rain means more drops, stronger wind means a higher, sharper whistle. Loudness is the Level field.
• Use the room presets sparingly. A forest or living room adds space; a cathedral turns rain into a wash.
• Longer loops (20–60 s) repeat less obviously.
• A different seed gives different drops, gusts and crackles with the same settings.
• For hum, use 100 Hz for 50 Hz mains (Europe) and 120 Hz for 60 Hz mains (North America): transformers hum at twice the mains frequency.
• Drone and hum frequencies are rounded to whole cycles per loop (a 0.05 Hz grid for a 20 s loop), which you cannot hear.

FAQ

Can I use the files in my video or game?

Yes. They are synthesized by your settings on our engine, not copied from recordings, so no third-party licence applies.

Why does stronger wind not get louder?

Every file is normalised to the level you choose. Strength changes the band-pass centre, its sharpness and the gust depth, which is what makes wind sound stronger.

How do I make the sound longer than 60 seconds?

Use a seamless loop and let your editor or player repeat it. The end flows into the start without a gap or click.

Is this the same sound as in the Soundscape Atlas app?

Yes. The app's procedural layers use the same engine and the same functions, and a test checks that both give identical files for the same settings.