Notes on audio, from people who live in it
Formats and bitrates, keys and tempo, edits and recordings. Plain answers to the questions our free tools get asked, no fluff, no farmed content.
Convert WhatsApp Voice Notes to MP3 (Free, Private)
WhatsApp voice notes are .opus files, and a surprising amount of software refuses to open them. Here is how to get the file off your phone and convert it to MP3 privately, right in your browser.
How to Make a Ringtone From a Song (Free, in Browser)
The best ringtone is the 20 to 30 seconds where the song becomes itself, not the intro. Here is how to cut it free in your browser and get it onto Android or iPhone, including the honest iPhone part.
How to Merge Audio Files Into One, Free and Private
Phone split your lecture in half, or your interview into three parts? Here is how to merge audio files into one clean file, and why naive concatenation gives you chipmunk audio when sample rates don't match.
OPUS vs MP3: Which Format Should You Actually Use?
Opus beats MP3 on quality per bit, dramatically at low bitrates. MP3 plays on everything. The right call is a compatibility decision, not a loyalty test.
How to Find the BPM of a Song: 3 Methods That Work
Three real ways to get a song's tempo: tap quarter notes by ear, read it in your DAW, or drop the file on a free in-browser analyzer. Plus how to dodge the half-time trap and handle tempo drift.
How to Find the Key of a Song: By Ear, Chords, or Analyzer
Three dependable ways to find a song's key: by ear, from the chords, or with a free in-browser analyzer. Plus what the Camelot wheel does and what to do with the key once you have it.
Best MP3 Bitrate for Music: 128 vs 192 vs 256 vs 320
An honest comparison of 128, 192, 256, and 320 kbps MP3: what the encoder actually discards, why converting a low bitrate up never helps, and which number fits archiving, demos, and car USB sticks.
FLAC vs MP3: What Lossless Really Means
Most people cannot reliably tell a 320 kbps MP3 from FLAC on normal gear, and that is fine. Here is what lossless actually buys you, when to convert each way, and what happens when you do.
WAV vs MP3: What Producers Should Use and When
WAV belongs inside the studio and MP3 belongs everywhere else. Here is where each format earns its place, and why bouncing to MP3 early is the mistake that surfaces a year later.
How to Make a Slowed and Reverb Edit (Free, in Browser)
The slowed and reverb aesthetic is three moves: slower tempo, lower pitch, and a wash of space. Here is how to make one in your browser, and how to pick the right amount of slowdown.
How to Make Nightcore (Free, in Your Browser)
Nightcore is the slowed and reverb edit run in reverse: sped up, pitched up, bright, and fast. Here is how to make one free in your browser, how much speed to add, and why the vocals come out sounding the way they do.
How to Record System Audio on Mac (Free, No Install)
Your Mac gives you no simple built-in way to record the sound it plays. Here is the free browser trick that captures system audio straight to WAV, plus the driver route for when you need more.
How to Change the Pitch of a Song (3 Ways That Sound Good)
Changing the pitch of a song means three different things: transposing into your vocal range, varispeed like tape, or slowing down for practice. Here is how each works and what it costs in sound quality.
Convert Voice Memos to MP3 (Free, Private, In-Browser)
iPhone voice memos are M4A files, and not everything plays them. Here is how to get a recording off your phone and convert it to MP3 in your browser, with nothing uploaded.
M4A vs MP3: Which Format Should You Actually Use?
AAC is the better codec on paper, but MP3 plays on everything. An honest look at when the difference matters and when converting costs more than it gains.
AIFF vs WAV: Same Audio, Different Wrapper
AIFF and WAV hold exactly the same uncompressed PCM audio. The real differences are metadata, platform history, and which software expects which wrapper.