Spectrum — Audio Analyzer

Spectrum shows which frequencies are in the room, right now.

It opens analysing: no settings to visit first, no start button.

• A logarithmic axis, the way the ear hears: an octave takes the same width low
down as high up, instead of squeezing every bass note into two pixels
• Colour says the frequency, height says the level: two things at a glance
instead of one
• Peak marks that fall slowly: a hand clap is still readable a moment after it
ended, instead of being a frame nobody sees
• The loudest frequency spelled out, in Hz or kHz
• Freeze the picture to study it — and while it is frozen the app says so,
because what you see is no longer the room

The level is in dBFS, relative to full scale: it is **not** a sound pressure
level. If you want to know how many decibels it is, that is a sound level
meter, and a different app.

What Spectrum does not do:
• no account, no sign-up
• **it does not record**: the sound is analysed in the phone's memory and
thrown away, and no file is ever written
• no location, no servers of ours

Underneath is an FFT written from scratch and checked by automated tests
against synthesised tones: an analyser is believed or it is decoration.

Permissions: microphone and Internet (ads only). The app is free and paid for
by ads: a banner at the bottom, away from the controls.

Privacy policy:
https://mindcontact.app/mcma-spectrum/privacy/

Recent changes:
The banner at the bottom no longer shifts the buttons when it appears.