This month one of my own masters went out of the render with the wrong label. The filename said 44.1 kHz. The file itself was 48 kHz. It got caught in the final check and renamed before delivery, but it's a good reminder of a simple rule: trust the file, not the name.
Filenames get typed by hand, copied from the last project and left alone after settings change. The file's own properties don't lie.
Why the numbers matter
Sample rate is how many times per second the audio is measured. 44.1 kHz and 48 kHz are the two you'll see most.
Bit depth is how much detail each measurement holds. 16-bit and 24-bit are the common ones.
Different destinations want different files. Streaming distributors take 44.1 or 48 kHz, and 24-bit is a safe choice. CD is fixed: 44.1 kHz, 16-bit, stereo. A pressing plant will send their exact specs, and those win.
Getting there takes real steps. Turning a 48 kHz, 24-bit master into a 44.1 kHz, 16-bit CD file means a sample rate conversion and dither. It's not a rename. It's a separate deliverable and should be treated like one.
How to check what you actually have
Open the file's properties. On a Mac, select it and press Command-I. On Windows, right-click, Properties, then Details. Look for sample rate, bit depth and channels.
Use a free inspector for more. A tool like MediaInfo shows every detail of the file in one window.
Check in your DAW. Most DAWs show the source format when you look at an item's properties. In REAPER it's in the media item properties.
Check after every render. Render settings stick from the last project. Look every time, not just when something seems off.
Name it so it can't drift
Put the specs in the filename, and set them from the file, not from memory. Something like:
Artist_Title_MASTER_48k24_v01.wav
When the version changes, the number changes. When the format changes, the tag changes. If you send a file to someone and the name says one thing, they should be able to open it and see the same thing.
When to bring it up
Tell your mastering engineer where the song is going before they start. Streaming only, CD, vinyl, sync, a video. Each one can mean a different final file. It's much easier to plan the deliverables up front than to find out the plant needs something else the week before the pressing.
Josh, Founder, JG BeatsLab
Want this handled on your track? I master AI-generated music by hand, one song at a time, and every master comes with a Mastering Dossier that shows what I did and why. Book mastering or take the 3-minute scorecard to see where your workflow stands.
