Applied AIMachine learningFormer CTO
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Senior / Lead Machine Learning EngineerApplied AIProduction ML Systems
Dr Carl Southall
Senior Machine Learning Engineer and former CTO with a PhD in Deep Learning and 10 years of experience developing and deploying production AI systems across diverse industries and technical domains. Combines extensive expertise in deep learning, generative AI, and multimodal modelling with a proven ability to adapt machine learning techniques to varied challenges and translate research into commercial products. Experienced in end-to-end ML development, cloud architecture, and engineering leadership, including building production systems at Logitech and co-founding an AI-powered startup that secured over £600k in investment.
- Co-founded and led an AI-powered startup as CTO
- Taking the product from concept to commercial launch, building the engineering team, and raising over £600k in investment.
- Delivered production audio ML at Logitech
- Developing speech enhancement technologies deployed across thousands of devices in the Rally Bar range. Contributed to the early development and prototyping of Logitech Sight, later recognised as one of TIME's Best Inventions of 2024.
- Led the development of cutting-edge AI at Cantine / Phiona
- Tackling the most mathematically and technically challenging problems of my career through advanced multimodal learning, generative AI, and psychological modelling.
- Combined a passion for music and problem-solving with academic research
- Completing a PhD in Audio Engineering and Deep Learning as the youngest person in the lab to earn a doctorate, with 12 research publications across journals, conferences, and workshops.
Work projects
Phiona
2024 – 2026Inferring psychological and behavioural traits from audio, with UCL.
Led research and development of self-supervised, multimodal and generative models that infer psychological and behavioural traits from audio.
WithMe
2023 – presentAn all-in-one platform for creators, co-founded and built as CTO.
Took WithMe from first prototype to a profitable commercial product, built its AI agent team and helped raise over £600k.
Speech Enhancement & Dereverberation
2020 – 2023Real-time deep learning audio on thousands of Logitech video conferencing devices.
Speech enhancement running every 10 ms on embedded chips, and a dereverberation system that improved PESQ by around 1.0.
Automatic Drum Transcription
2015 – 2019PhD research on deep learning for transcribing drums from audio.
Deep learning approaches to automatic drum transcription, including ADTWeb, an open source browser-based system, and the MDB Drums dataset.
Personal projects
Things I build outside work to try new and state-of-the-art techniques. Each write-up covers what I built, how, and what I learned.
CV AI Assistant
2026How I built the assistant on this site: grounded in my CV, guarded, evaluated and cheap to run.
A Claude Haiku 5.5 assistant that answers recruiters' questions from my real experience. Django, Postgres and Next.js on AWS, with prompt caching and an eval of factual and adversarial questions graded by code checks and a judge model.
Semantic Image Search
2026Describe a photo and find it among 20,000, with CLIP running entirely in your browser.
Text-to-image search over 20,000 openly licensed photos. CLIP ViT-B/16 with an int8 index 4x smaller than float32 at no loss in accuracy, evaluated on COCO; no server, so searches never leave your device.
Experience
- Apr 2023 – PresentRemote
Co-Founder & CTO
WithMe
- Co-founded WithMe, an all-in-one platform for creators, and led engineering from first prototype to a profitable commercial product, helping raise over £600,000 across multiple funding rounds.
- Designed and built WithMe's AI agent team, a multi-agent system that acts as a back office for each creator. It cut the time to build a creator hub to minutes and saved creators hundreds of hours by automating recurring marketing, sales, support and design work. Otto, a planner agent, delegates tasks to specialist agents (Margo, Sal, Cassie and Dez). The specialists use tools to act on the platform, draw on a shared memory of each creator's brand and audience, and pass key actions to the creator for approval. A feedback system captured creator ratings and edits to refine prompts and evaluation sets.
- Defined the key product metrics and, through user feedback loops and rapid iteration towards product-market fit, cut monthly churn from 18% to 8% and lifted trial conversion from 32% to 46%.
- Owned and scaled the full technical architecture across web, mobile, payments, analytics and AI, built on AWS, including a live and recorded video pipeline (IVS, MediaConvert), containerised and serverless back-end services (ECS Fargate, Lambda), and managed data and content delivery (RDS, S3, CloudFront).
- Hired and mentored a team of three early-career engineers, growing them into engineers who owned production features from design to deployment, through pair programming, code review, CI/CD and shared engineering standards.
- Dec 2024 – Feb 2026Hybrid, London, United Kingdom
Lead Audio Machine Learning Engineer
Cantine / Phiona
- Led the research and development of deep learning models that infer psychological and behavioural traits from audio. This is a hard problem: labelled data is scarce and labels are subjective, so used self-supervised pre-training and representation learning on large unlabelled audio datasets, then fine-tuned Transformer models on smaller annotated sets.
- Built multimodal and generative models combining audio with behavioural signals, using GANs and other generative approaches for audio synthesis and data augmentation. Designed the full ML pipeline from data collection and annotation through training, statistical evaluation and benchmarking to production deployment.
- Conducted applied research with University College London (UCL) across audio ML, generative AI and computational psychology, and built and led a team of three engineers, introducing CI/CD, automated testing and experiment tracking to take research models into production.
- Dec 2020 – Apr 2023Hybrid, Windsor, United Kingdom
Senior Audio Machine Learning Engineer
Logitech
- Improved the deep learning speech enhancement model running on thousands of Logitech video conferencing devices worldwide, raising audio quality across real-world rooms, noise conditions and languages. The models ran in real time on low-power embedded chips, processing a new audio frame every 10 ms with compute budgets as low as 2 MFLOPS.
- Led the end-to-end development of a deep learning dereverberation system that improved PESQ by around 1.0, from model architecture and training through hyperparameter optimisation to production deployment, and prototyped early Transformer and convolutional architectures that shaped later production models.
- Designed and ran large-scale audio dataset collection and annotation across rooms, devices, languages and noise conditions, and built the evaluation framework and objective metrics used to benchmark every speech enhancement and dereverberation model before release.
- Jan 2020 – Dec 2020Derby, United Kingdom
Senior Machine Learning Analyst
Incora / Pattonair
- Identified new opportunities through top-down analysis and working closely with colleagues, guiding the future direction of the team and business.
- Delivered a ~£4,000,000 annual working capital reduction by increasing the accuracy of the machine learning forecast engine through new features and more advanced machine learning architectures.
- Established process, coding, project and testing quality standards across the whole data science team, ensuring high performance output.
- May 2019 – Jan 2020Manchester, United Kingdom
Machine Learning Specialist
Music Tribe
- Developed the first AI application for live sound audio: Channel AI.
- Lead author and developer of the in-house machine learning library.
- Championed and led the team on multiple industry-first machine learning projects.
- Gathered, processed, stored and utilised large amounts of data.
- Advanced colleagues' machine learning knowledge through presentations.
- Oct 2018 – May 2019Birmingham, United Kingdom
Research Associate / Software Engineer / Machine Learning Engineer
Semantic Audio Labs Ltd
- Pioneered all machine learning and deep learning research and products.
- Delivered seven state-of-the-art machine learning algorithms.
- Provided expert advice on the future direction of the company.
- Participated in all project meetings with company leaders and external stakeholders.
Research & education
My PhD focused on deep learning for automatic drum transcription, with work published at ISMIR, DAFx and in IEEE/ACM TASLP.
Publications
- Sept 2018Audio Style Transfer with Rhythmic Constraints
21st International Conference on Digital Audio Effects (DAFx), Aveiro, Portugal, pages 45-50
- Sept 2018Improving Peak Picking using Multiple Time-step Loss Functions
International Society for Music Information Retrieval Conference (ISMIR), Paris, France, pages 313-320
- Sept 2018Player Vs Transcriber: A Game Approach to Data Manipulation for Automatic Drum Transcription
International Society for Music Information Retrieval Conference (ISMIR), Paris, France, pages 58-65
- Jun 2018Player Recognition for Traditional Irish Flute Recordings
8th International Workshop on Folk Music Analysis (FMA), Thessaloniki, Greece
- Apr 2018A Review of Automatic Drum Transcription
IEEE/ACM Transactions on Audio, Speech, and Language Processing, 26(9), pages 1457-1483
Show all 12 publications ↓Show fewer ↑
- Oct 2017ADTWeb: An Open Source Browser Based Automatic Drum Transcription System
International Society for Music Information Retrieval Conference (ISMIR), Suzhou, China
- Oct 2017Automatic Drum Transcription for Polyphonic Recordings using Soft Attention Mechanisms and Convolutional Neural Networks
International Society for Music Information Retrieval Conference (ISMIR), Suzhou, China, pages 606-612
- Oct 2017MDB Drums: An Annotated Subset of MedleyDB for Automatic Drum Transcription
International Society for Music Information Retrieval Conference (ISMIR), Suzhou, China
- Oct 2017MIREX 2017 Drum Transcription Systems
International Society for Music Information Retrieval Conference (ISMIR), Suzhou, China
- Jul 2017Automatic Drum Transcription using Recurrent Neural Networks
16th Rhythm Production and Perception Workshop (RPPW), Birmingham, United Kingdom
- Jul 2017Rhythm Modelling Using Convolutional Neural Networks
Rhythm Production and Perception Workshop (RPPW), Birmingham, United Kingdom
- Jun 2016Note, Cut and Strike Detection for Traditional Irish Flute Recordings
International Workshop on Folk Music Analysis (FMA), Dublin, Ireland
Education
PhD, Audio Engineering and Deep Learning
Birmingham City University · 2015–2019
Postgraduate Certificate of Research, Audio Engineering and Deep Learning
Birmingham City University · 2015–2016
BSc, Sound Engineering and Production
Birmingham City University · 2012–2015
Final year project: Automatic Classification of Drum Sounds using Machine Learning
Awards
Doctoral Bursary
Birmingham City University · 2015
Skills
ML & AI
Audio
Engineering & cloud
Leadership
Strengths
Outside work
Get in touch
I'm always happy to talk about machine learning, audio AI, or building products. The best way to reach me is by email.