Machine Learning Engineer - Voice AI & Generative Music (Part-time)

About the Position

Machine Learning Engineer - Voice AI & Generative Music (Part-time)

Remote · Spain · Mexico

About the Company

MWDN is a global IT outstaffing company with 23+ years of experience that connects exceptional tech talent with leading companies across Israel, the USA, Great Britain, and Western Europe. We offer opportunities to work on international products in a stable and professional environment.

Why Choose Us?

• Security: We carefully vet our clients to minimize risks and ensure reliability and timely payments - no fraud or unpleasant surprises.
• Career Support: If a project isn’t the right fit, we support you and actively help find new opportunities that match your skills and career goals.
• Legal Assistance: We provide guidance on legal matters, including opening and managing your independent contractor or sole proprietorship status, taxes, and related processes.
• Professional Development: We offer English courses and professional growth opportunities, as well as team-building events.

About the Project

Domain: Music Technology / Voice AI / Generative AI

An AI-native music label developing advanced tools for producing and releasing Spanish-language music. Artificial intelligence serves as the foundation of its production process, powering artist-consistent audio generation, vocal cloning, custom text-to-speech, and generative lyrics.

Responsibilities

1. Custom Singing Voice Model

   • Fine-tune and improve an existing singing-voice conversion and cloning model, increasing its current 70–75% fidelity baseline to production-level quality of 90% or higher in blind listening tests.
   • Reproduce expressive vocal characteristics beyond basic timbre, including vibrato, falsetto, dynamics, and both spoken and sung delivery.
   • Evaluate different improvement strategies, including expanding the training dataset, testing alternative base models, and assessing enterprise APIs that offer no-training guarantees.

2. Text-to-Speech Model

   • Take ownership of an existing validated LoRA fine-tune based on Chatterbox Multilingual for a Spanish-speaking voice.
   • Ensure accurate reproduction of a Mexican accent and correct pronunciation of sounds and letters such as J, Ñ, and X.
   • Containerize the model and deploy it as a serverless inference endpoint using RunPod or a similar platform.
   • Integrate the endpoint with the existing web platform through an API.
   • Train a second version using clean studio recordings to eliminate the remaining output instability.

3. ALMA - Spanish Lyrics Model

   • Develop a proprietary Spanish-language lyrics-generation model, with experience in regional Mexican genres considered a strong advantage.
   • Build the solution using an open-weight LLM, LoRA fine-tuning, preference optimization through DPO, and RAG based on a curated content corpus.
   • Establish clear evaluation criteria and organize quality assessment with native Spanish speakers.
   • Integrate the completed model into the existing frontend.

Requirements

• 3+ years of experience training and deploying deep learning models in production, preferably within audio or NLP.
• Hands-on experience in at least two of the following areas: Voice cloning or Singing Voice Conversion (SVC), Text-to-Speech model fine-tuning, LLM fine-tuning using techniques such as LoRA, DPO, and RAG.
• Strong proficiency in PyTorch.
• Practical experience with GPU cloud infrastructure, such as RunPod or AWS, as well as Docker and serverless inference.
• A rigorous, evidence-based approach to model evaluation, including benchmarks, ablation studies, and blind testing.
• Native or strong professional proficiency in Spanish, required for lyrics evaluation and voice quality assurance.

Nice to Have

• A music background or experience with music-production tools and workflows, including stems, MIDI, and DAWs.
• Experience with singing-voice synthesis solutions such as ACE Studio, ACE-Step, RVC, so-vits-svc, or similar technologies.
• Previous experience working with licensed celebrity or artist voices and consent-based voice AI.

We Offer

• People-first management with minimal bureaucracy
• A friendly company culture, proven by employees who choose to return
• Flexible working hours
• 29 days of PTO (18 working days per year plus all national holidays)
• 10 paid recovery days
• Full financial and legal support for independent contractors
• Free English classes, with native speakers or Ukrainian teachers
• Dedicated HR support

Our Next Steps

1. Intro call with a Recruiter
2. Intro call with a client
3. Final client interview
4. Offer

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