# AI Harmonizer: Expanding Vocal Expression with a Generative Neurosymbolic Music AI System

arXiv: https://arxiv.org/abs/2506.18143 · HTML: https://mlsanity.com/paper/2506.18143/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- Builds on 8 of its 27 references that are in the map.
- First posted on arXiv 22 Jun 2025.

## Builds on (most cited first, 8 of 8)

- [HuBERT: Self-Supervised Speech Representation Learning by Masked Prediction of Hidden Units](https://mlsanity.com/paper/2106.07447/) (2021)
- [Conditional Variational Autoencoder with Adversarial Learning for End-to-End Text-to-Speech](https://mlsanity.com/paper/2106.06103/) (2021)
- [Counterpoint by Convolution](https://mlsanity.com/paper/1903.07227/) (2019)
- [RMVPE: A Robust Model for Vocal Pitch Estimation in Polyphonic Music](https://mlsanity.com/paper/2306.15412/) (2023)
- [Chord Generation from Symbolic Melody Using BLSTM Networks](https://mlsanity.com/paper/1712.01011/) (2017)
- [AccoMontage2: A Complete Harmonization and Accompaniment Arrangement System](https://mlsanity.com/paper/2209.00353/) (2022)
- [Melody Harmonization Using Orderless NADE, Chord Balancing, and Blocked Gibbs Sampling](https://mlsanity.com/paper/2010.13468/) (2020)
- [Local deployment of large-scale music AI models on commodity hardware](https://mlsanity.com/paper/2411.09625/) (2024)

## Built on by (most cited first, 1 of 1)

- [Harmonic Representations in Symbolic Music Transformers are Localized and Controllable](https://mlsanity.com/paper/2610.15957/) (2026)

## Abstract (arXiv)

Vocals harmonizers are powerful tools to help solo vocalists enrich their melodies with harmonically supportive voices. These tools exist in various forms, from commercially available pedals and software to custom-built systems, each employing different methods to generate harmonies. Traditional harmonizers often require users to manually specify a key or tonal center, while others allow pitch selection via an external keyboard-both approaches demanding some degree of musical expertise. The AI Harmonizer introduces a novel approach by autonomously generating musically coherent four-part harmonies without requiring prior harmonic input from the user. By integrating state-of-the-art generative AI techniques for pitch detection and voice modeling with custom-trained symbolic music models, our system arranges any vocal melody into rich choral textures. In this paper, we present our methods, explore potential applications in performance and composition, and discuss future directions for real-time implementations. While our system currently operates offline, we believe it represents a significant step toward AI-assisted vocal performance and expressive musical augmentation. We release our implementation on GitHub.