What File Formats Should You Send to a Session Drummer?
What File Formats Should You Send to a Session Drummer?
You have written a brilliant song. You have found a session drummer you trust. Now comes the part that trips up more musicians than you might expect: actually sending the files. The wrong format, a missing tempo map, or a bounced MP3 instead of a WAV can delay your project by days — and nobody wants that.
Over 3,758 recording sessions, I have seen every possible file preparation scenario. Some artists send perfectly organised folders with colour-coded stems. Others send a voice memo recorded in a car. Both can work, but one makes the process dramatically smoother. Here is everything you need to know.
WAV vs MP3: Why It Matters
Always send WAV files. Full stop. MP3 is a lossy compression format — it throws away audio information to reduce file size. When I record drums to your track and you later combine everything in your mix, that lost information means degraded audio quality stacking up across every element.
WAV files preserve the full audio spectrum. They are larger, yes, but services like Google Drive, Dropbox and WeTransfer handle them without issue.
If you only have an MP3 of your rough demo, that is fine as a reference — but your actual stems (the individual instrument tracks I will play along to) should always be uncompressed WAV.
Sample Rate and Bit Depth
The standard professional sample rate is 44.1 kHz or 48 kHz at 24-bit. Either works perfectly. I record at 48 kHz / 24-bit in Pro Tools as my default, but I can match whatever your session requires.
The key rule: do not upsample. If your project was recorded at 44.1 kHz, do not convert it to 96 kHz before sending. Upsampling does not add quality — it just creates larger files. Send files at whatever sample rate they were originally recorded in, and let me know what that is.
Mono vs Stereo Stems
Individual instruments — guitar, bass, vocals — should typically be exported as mono files unless they were recorded in stereo (like a stereo acoustic guitar pair or a keyboard pad). Stereo files are twice the size for no benefit if the source is mono.
If you are unsure, just export everything as stereo. I will sort it out. But if you want to be efficient, mono for single-source instruments and stereo for anything that was genuinely recorded or processed in stereo.
The Tempo Map Is Everything
This is the single most important element you can provide. A clear tempo map — even if it is just a text note saying "120 BPM throughout" or "starts at 90 BPM, jumps to 110 at the chorus" — saves enormous time.
If your song was recorded without a click and the tempo drifts, tell me. I can work with natural tempo fluctuations, but I need to know they exist rather than discovering them bar by bar.
The ideal scenario: export a MIDI tempo map from your DAW along with your stems. In Pro Tools, Logic, Ableton or any major DAW, this takes under a minute and gives me an exact roadmap of your song's timing.
Click Tracks: To Include or Not
If you recorded to a click, bounce that click as a separate WAV file and include it. This is enormously helpful — it lets me lock in immediately with the exact feel your track was built on.
If you did not use a click, do not create one after the fact. Instead, send me a note about the feel and any tempo variations. I have been playing for over 35 years; I can lock into a natural, unquantised performance without a click. But I need to know that is what I am working with.
Reference Tracks and Notes
A reference track is any commercially released song (or section of a song) that captures the drum sound or feel you are after. This is worth a thousand words of description. "I want something like the verse groove in Rosanna by Toto" tells me infinitely more than "I want something groovy."
Equally valuable: a rough mix. Even if it has programmed drums or just a basic beat, hearing your complete vision helps me serve the song rather than just play what I think sounds good.
How to Organise Your Files
The ideal folder structure looks like this:
• Song_Title_Stems (folder)
- Bass.wav
- Guitar_Electric.wav
- Guitar_Acoustic.wav
- Keys.wav
- Vocals_Lead.wav
- Click.wav
- Rough_Mix.wav
• Notes.txt (tempo, feel, references, section breakdown)
Label everything clearly. "Audio_Track_14.wav" helps nobody.
A Quick Checklist Before Sending
1. All stems are WAV, 44.1 or 48 kHz, 24-bit
2. All stems start from the same point (bar 1, beat 1)
3. Tempo information is included (BPM, tempo map, or a note about feel)
4. Click track included if one exists
5. Rough mix included for context
6. A brief note about the sound and feel you are after
7. Reference songs if applicable
Getting this right means I can start recording the same day your files arrive. At tonimateos.com, most sessions are turned around within 48 to 72 hours — but that timeline depends heavily on receiving well-prepared files. Take ten extra minutes to organise your stems properly, and you will hear the difference in the final result.
Related articles: