stereo2spatial-v2-binaural converts mono or stereo music directly into two-channel
binaural audio at 48 kHz. It is a raw-waveform conditional flow model and does
not use EAR-VAE or a separate HRTF rendering stage like v1.
Weights: EMA from cumulative checkpoint step_0660000
Sample rate: 48000
Input channels: 2 (stereo; mono input is duplicated by the runtime)
Output: direct binaural stereo
Output channel order: FL, FR
Patch size: 200 samples
Hidden size: 896
Layers: 12
Attention heads: 14
Memory tokens: 32
Mix-style conditioning dimensions: 10
The bundle defaults to RES6S with four steps, 10-second windows, 2-second
overlap, and timestep-major traversal. Timestep-major inference carries model
memory across every window at a shared solver timestep before advancing the
solver, matching the long-audio training schedule.
Training Summary
This release contains 660,000 total training updates:
600,000 base-training updates with 10-, 18-, 26-, and 34-second sequences
60,000 long-context updates initialized from the base model's EMA weights,
using 122-second sequences
Both stages used 10-second model windows with 2-second overlap, EMA with a
decay of 0.999, and no adversarial loss. Mix-style conditioning used a 20%
dropout probability, so the model supports both conditioned and unconditioned
generation.
Mix-Style Conditioning
Mix-style conditioning is optional. Omitting a mix-style argument performs an
unconditioned generation. The balanced preset is a conditioned neutral vector
and is not the same as unconditioned generation.
For this direct-binaural model, the ten normalized conditioning dimensions are:
research and experimentation in stereo-to-binaural music generation
local CUDA inference for headphone-oriented spatial audio
prototyping immersive music and audio applications
It is not a replacement for professional mastering, broadcast authoring, or
formal delivery-quality control.
Limitations
The model produces direct binaural stereo for headphone playback. It does not
produce a speaker layout or discrete surround channels.
Training used stereo conditioning. Mono files are accepted by duplicating the
channel, but mono was not part of this model's training distribution.
The model is designed for music at 48 kHz. Other content and sample rates may
produce weaker results even when the runtime resamples them.
(Model was trained with a 15% chance for the input to be resampled to 44.1 kHz.
So it should be able to handle 44.1 kHz reasonably well.
But other sample rates were not part of the training distribution.)
Mix-style values are normalized, corpus-relative controls rather than physical
acoustic units.
Results depend on the source and seed and may contain artifacts, unstable
imaging, or undesirable balance changes. Manual listening and QC are required.
License
The model weights and bundle metadata are released under the Apache License 2.0.
See LICENSE.
Acknowledgements
Compute for the stereo2spatial-v2 training run was provided by SERP, which
supplied two NVIDIA RTX A6000 GPUs for approximately 20 days of training: about
10 days for Stage 1 and 10 days for Stage 2. Special thanks to
SERP Apps,
SERP AI, and
Devin Schumacher for supporting the
project.