Quickstart: your first immersive mix

Turn a stereo song or a set of stems into an immersive mix, check it on headphones and export it.

This quickstart takes you from a finished song to an exported immersive mix. You prepare your audio, upload either a stereo master or a set of stems, let Spatial9 generate the spatial arrangement, review the result on headphones and export the formats your destination expects.

The page is written for musicians, producers and students who are using Spatial9 for the first time. No immersive speaker setup is required: you can complete every step with a pair of ordinary headphones. If you want to automate this process from an AI assistant, an agent or your own code instead, read Choose the right workflow after this page.

Before you begin

Check the following requirements before you upload anything.

Step 1: Choose your starting point

Your first decision is whether to start from a single stereo master or from stems. Both routes lead to the same kind of immersive mix, but they differ in preparation time and precision.

Choose the stereo master when the original session is lost, when you are converting many songs and need consistent results, or when the mix is fairly open with clear space between the main parts. Choose stems when you still have the session, when many parts share the same frequencies, or when you want exact control over where each part sits.

For a detailed comparison, including what streaming platforms accept, see Upmixing stereo vs mixing from stems.

Step 2: Prepare your files

Clean, consistent input gives the engine clear information about each part of the music. Problems in the source cannot be fully fixed later.

Preparing a stereo master

1. Export the final approved mix as lossless WAV or FLAC. Avoid MP3 when you have a lossless version.
2. Leave some headroom. Avoid a master that is limited so hard that the peaks are flattened, because a crushed master gives separation less detail to work with.
3. Keep the full length of the song, including intro and outro.

Preparing stems

Apply every rule in the following checklist before you export.

See Preparing and exporting stems for the complete reference.

Step 3: Write a creative brief

Write one paragraph that describes what the immersive mix should feel like before you hear what Spatial9 proposes. Without a brief, it is easy to accept whatever sounds impressive; with a brief, you can judge whether the result serves the song.

Include the genre, the mood, where the listener should feel they are, and what must stay focused. Use spatial vocabulary: position, width, height, distance, envelopment and clarity.

A slow, intimate indie song. The listener should feel like they are sitting in a small room with the band. The lead vocal stays close and centered in front. Guitars sit slightly left and right, not behind. Reverb and pads gently wrap around and rise above, but never cover the voice. The chorus should open up wider than the verse.

Step 4: Upload and process

1. Sign in at app.spatial9.ai.
2. Create a new music project.
3. Upload your stereo master, or upload your full set of stems.
4. Start processing.

During processing, Spatial9 analyzes the material, separates sources if you supplied only a stereo master, and uses GravityLLM to generate the spatial arrangement: where each source sits, its distance, its elevation and its movement over time. AI agents then coordinate processing and rendering.

Processing time depends on the file length and complexity. A typical 3-minute song takes 2 to 5 minutes, and you receive an email notification when the file is ready.

To hear how the modes work before using your own music, open the Music Transformation room at /demo/music. Under "Choose a mode" it offers "3D Spatial Audio", "Interactive Mode" and "Your Stems + AI". In "Your Stems + AI", GravityLLM positions uploaded stems in 3D space based on genre and you review the result in a stage player.

Step 5: Review on headphones

Do not judge the result on a single listen. Use a structured review at a fixed, moderate level.

1. Set a comfortable, moderate listening level and keep it constant for the whole review.
2. Listen to the whole track once without interruption, ideally with your eyes closed.
3. Listen again with one focus per pass: the lead vocal, the low end, the overall space, then individual parts.
4. Draw a simple listening map of where you hear each part.
5. Compare the map with your creative brief, line by line.
6. Compare the immersive version with the original stereo version.

Use the following checks on every review.

If you can, repeat the review on a soundbar, TV or speaker system, and on phone speakers, where many people will hear the result. See Binaural rendering, headphones and speakers for playback details.

Step 6: Refine

When something does not match your brief, find the cause before you change anything. Most fixes happen at the source level.

• A vocal smeared by printed reverb may need a drier stem export.
• A crowded stem that holds both guitars and keys may work better split into two stems.
• A clipped stem needs more headroom.
• A stereo master with heavy separation artifacts may work better as stems, if they are available.

Change one thing at a time, process again, and review again with the same procedure and at the same level. Record what you changed and what you heard. Spatial9 also lets you adjust the mix directly; the available controls, movement options and effects are described in Spatializer for Music.

Step 7: Export

When the mix meets your brief, export the formats your destination needs. Available formats depend on your plan.

Binaural is the format most headphone listeners will hear. It is a normal two-channel file carrying 3D cues, so it plays on any headphones without special hardware. Keep a stereo version as a safety format for listeners whose playback does not support 3D.

Delivery checklist

1. Identify who is listening, and on what: headphones, speakers, VR or video.
2. Choose the primary format that most of your audience will hear.
3. Add a safety format, usually a stereo mixdown.
4. When exporting to a smaller speaker layout, check how height content folds down.
5. Confirm that no clipping occurred.
6. Name files clearly with song, format and version.
7. Listen to the delivered file, not only to the session.

Step 8: Test and publish

Play the exported binaural file on at least three devices, including at least one pair of everyday earbuds. Headphones differ in tone and in how they present space. Note anything that changes significantly between devices, such as a vocal that drifts or bass that disappears on earbuds.

After uploading to a platform, confirm that the immersive version actually plays on a supported device before you announce it. For YouTube delivery with Eclipsa Audio, see Publishing and delivery.

Troubleshooting

Next steps

• Core concepts: understand objects, beds, rendering and binaural before your next mix.
• Spatializer for Music: learn the controls, movement library and effects in detail.
• Preparing and exporting stems: get stems right the first time.
• Publishing and delivery: choose the right destination and file for each platform.