How to Send Music Stems and Large Audio Files from Your Mac
Stems are too big for email and too important to compress. Here's how to send WAV files, project folders, and stems from Logic Pro or GarageBand.
You’ve finished a mix. The client needs the stems. You open the project, bounce 24 tracks as WAVs, and end up with a folder that’s 4.7 GB.
Now what?
Email won’t work — 25 MB limit. Google Drive will take 30 minutes to upload and the client won’t know how to download a folder. WeTransfer caps at 2 GB on free. You could compress to MP3, but the mixing engineer specifically said “WAVs only, 24-bit, no compression.”
Here’s how to actually send them.
Why stems are so big
A quick reference for common audio file sizes:
| Format | Sample rate | Bit depth | Per minute | 10 tracks × 4 min |
|---|---|---|---|---|
| WAV | 44.1 kHz | 16-bit | ~10 MB | ~400 MB |
| WAV | 44.1 kHz | 24-bit | ~15 MB | ~600 MB |
| WAV | 48 kHz | 24-bit | ~17 MB | ~680 MB |
| WAV | 96 kHz | 24-bit | ~34 MB | ~1.4 GB |
| AIFF | 48 kHz | 24-bit | ~17 MB | ~680 MB |
A full song with 20-30 stems at 48kHz/24-bit easily reaches 3-6 GB. At 96kHz, you’re looking at 10+ GB. These aren’t edge cases — this is standard delivery for professional mixing and mastering.
Step 1: Prepare your stems properly
Before worrying about how to send them, make sure they’re ready:
Export from Logic Pro: File > Bounce > Project or Section > select “All Tracks as Audio Files” > WAV > 24-bit > match your project’s sample rate.
Export from GarageBand: Share > Export Song to Disk > WAV (uncompressed). Note: GarageBand bounces a stereo mix, not individual stems. For stems, you’ll need to solo each track and export one at a time.
Export from Ableton / Pro Tools / other DAWs: Each DAW has its own export workflow, but the principle is the same: export each track individually as WAV, matching the project’s sample rate and bit depth.
Naming convention: Name your stems clearly. Your mixing engineer doesn’t want to open 24 files named “Audio 1.wav” through “Audio 24.wav.”
SongTitle_Stems_48k24b/
├── 01_Kick.wav
├── 02_Snare.wav
├── 03_HiHat.wav
├── 04_Bass_DI.wav
├── 05_Bass_Amp.wav
├── 06_Guitar_L.wav
├── 07_Guitar_R.wav
├── 08_Keys.wav
├── 09_Vocal_Lead.wav
├── 10_Vocal_BG_L.wav
├── 11_Vocal_BG_R.wav
└── README.txt (tempo, key, sample rate, any notes)Include a README with the BPM, key, sample rate, bit depth, and any session notes. Your engineer will thank you.
Step 2: Send them
For any size: Swooshare
Select the stems folder in Finder, shake your mouse, and Swooshare uploads the folder and gives you a share link. The recipient downloads the entire folder structure intact — no re-zipping, no missing files.
There’s no file size limit on any plan — even the free tier handles large stem folders without issues.
The share page includes a chat, so your engineer can leave notes like “missing the vocal reverb send” without starting a separate email thread.
For stems 2-50 GB: SwissTransfer
Browser-based, 50 GB free, no account. Upload the folder (or a ZIP), get a link. Files available for 30 days.
The upload happens through the browser, so keep the tab open until it’s done. For a 6 GB folder on a 50 Mbps upload connection, expect about 15-20 minutes.
For stems 50+ GB or when speed matters: MASV
Pay-per-GB ($0.25/GB). The fastest upload and download speeds of any transfer service. MASV is the industry standard for sending large media files — studios, post-production houses, and game developers use it.
If you’re sending a full multitrack session (50+ GB) and the deadline is today, MASV is worth the cost. A 50 GB upload that takes 3 hours on SwissTransfer might take 30 minutes on MASV.
Physical delivery: the sneakernet
For very large sessions (100+ GB, or full ProTools sessions with plugins), sometimes the fastest option is an SSD in the mail.
Format a portable SSD as exFAT (works on Mac and Windows), copy the session, ship it overnight. A 2 TB SSD shipped via FedEx has more bandwidth than most internet connections.
What NOT to do
Don’t compress to MP3/AAC. If someone asks for stems, they need lossless audio. Lossy compression removes data that can’t be recovered. Even “320kbps MP3” is not acceptable for mixing or mastering.
Don’t use FLAC for stems (usually). FLAC is lossless compression, so it preserves quality. But most DAWs don’t natively import FLAC. Your engineer will have to convert them back to WAV, which adds a step. Unless they specifically ask for FLAC, send WAV.
Don’t upload to SoundCloud or YouTube. These platforms compress everything. They’re for listening, not for delivering source material.
Don’t split into multiple emails. Attaching one stem per email (to stay under the 25 MB limit) means your engineer receives 24 separate emails and has to manually download and organize each one.
Don’t forget the session info. A folder of stems without tempo, key, or sample rate information is a puzzle. Always include a README or a note.
Quick reference
| Situation | Best method | Notes |
|---|---|---|
| Daily sharing + chat | Swooshare | 5 GB per share (free), unlimited (Pro). In-page chat for session notes |
| One-off large session | SwissTransfer | Up to 50 GB free, browser upload |
| Deadline is today | MASV | Fastest speeds, $0.25/GB |
| Massive session (50+ GB) | Physical SSD | Ship overnight |
The tools exist to send stems at any size without compression. There’s no reason to degrade your audio to fit an email limit.