Whisper-Large-v3 Dutch - Full Synthetic Data (Unfiltered)
This model is a fine-tuned version of openai/whisper-large-v3 for Dutch automatic speech recognition (ASR). It was trained on Common Voice 17.0 Dutch combined with all synthetic speech data without quality filtering, representing the maximum data augmentation approach.
Introduction
Purpose
This model uses all available synthetic data without WAVe quality filtering to evaluate the impact of maximum data augmentation for the largest Whisper model. It achieves excellent performance (4.44% Test WER) but requires significantly more training steps than filtered approaches, demonstrating the quality-vs-quantity tradeoff in synthetic data augmentation.
How the Data Was Created
The training data combines real speech from Common Voice 17.0 with the complete synthetic dataset:
Transcript Generation: We used GPT-4o-mini to generate Dutch transcripts that match the word count distribution observed in Common Voice, ensuring realistic utterance lengths and diverse linguistic content.
Speech Synthesis: Each transcript was converted to audio using OpenAI's TTS-1 model with 9 different voice variants (alloy, ash, coral, echo, fable, nova, onyx, sage, shimmer), producing 34,898 synthetic samples.
No Quality Filtering: Unlike other models in this series, no WAVe filtering was applied. All 34,898 synthetic samples were used, including those with potential synthesis defects.
How the Model Was Created
The model was fine-tuned from openai/whisper-large-v3 using the Hugging Face Transformers library:
Mixed Training: Combined 34,952 real speech samples from Common Voice 17.0 Dutch with all 34,898 synthetic samples (69,850 total).
Optimization: Trained for 5 epochs with a learning rate of 5e-6, global batch size of 256, and BF16 precision on an NVIDIA H200 GPU.
Checkpoint Selection: The best checkpoint was selected based on validation loss, occurring at step 450 with a validation loss of 0.0564.
This approach achieves strong ASR performance but requires 100% more training steps than training on Common Voice only.
Model Details
Property
Value
Base Model
openai/whisper-large-v3
Language
Dutch (nl)
Task
Automatic Speech Recognition (transcribe)
Parameters
1550M
Training Data
Common Voice 17.0 + All Synthetic (Unfiltered)
Total Training Samples
69,850
Sampling Rate
16kHz
Evaluation Results
This Model (whisper-large-v3-cv-fully-synthetic-nl)
Metric
Value
Validation Loss
0.0560
Validation WER
3.61%
Test WER (Common Voice)
4.44%
Test WER (MLS)
17.02%
Best Checkpoint
Step 450
Max Training Steps
1,365
Comparison with Other Training Configurations (Whisper-Large-v3 Dutch)
Training Data
Max Steps
Val Loss
Val WER
Test WER (CV)
Test WER (MLS)
Common Voice Only
680
0.0549
3.56%
4.39%
22.43%
High-Quality Filtered + CV
890
0.0520
3.57%
4.43%
20.29%
Mid-High Quality Filtered + CV
1,270
0.0570
3.63%
4.48%
17.25%
All Synthetic + CV (Unfiltered)
1,365
0.0560
3.61%
4.44%
17.02%
Key Performance Highlights
Best cross-domain generalization on MLS benchmark (17.02% WER)
Competitive in-domain performance: 4.44% Test WER on Common Voice (within 0.05% of baseline)
24.1% relative improvement on MLS vs baseline (17.02% vs 22.43%)
Tradeoff: Requires 1,365 steps vs 680 for CV-only (100% more compute)
This model demonstrates the tradeoff between data quantity and quality for Whisper-Large-v3:
Approach
Synthetic Samples
Training Steps
Test WER (CV)
Test WER (MLS)
CV Only
0
680
4.39%
22.43%
High-Quality (q≥0.8)
10,555
890
4.43%
20.29%
Mid-High (q≥0.5)
30,182
1,270
4.48%
17.25%
Unfiltered (this model)
34,898
1,365
4.44%
17.02%
Key insight: For Whisper-Large-v3, unfiltered synthetic data provides the best cross-domain generalization (17.02% MLS WER), suggesting that the large model capacity can effectively leverage even lower-quality synthetic samples for improved robustness.
Limitations
Training efficiency: Requires most compute among all configurations
Noisy training signal: Includes low-quality synthetic samples (13.5% with q < 0.5)
Domain specificity: Optimized for general Dutch; may underperform on technical domains
Dialect coverage: Performance may vary across Dutch regional variants
Citation
This model is part of research on WAVe (Word-Aligned Verification) for synthetic speech quality assessment. While the WAVe methodology paper is currently under review, please cite our previous work that motivated this research:
bibtex
1@article{perezhohin2024enhancing,
2 title={Enhancing Automatic Speech Recognition: Effects of Semantic Audio Filtering on Models Performance},
3 author={Perezhohin, Yuriy and Santos, Tiago and Costa, Victor and Peres, Fernando and Castelli, Mauro},
4 journal={IEEE Access},
5 year={2024},
6 publisher={IEEE}
7}
89@article{perezhohin2026wave,
10 title={WAVe: Word-aligned verification of synthetic speech for ASR},
11 author={Perezhohin, Yuriy and Castelli, Mauro},
12 journal={Information Sciences},
13 pages={123591},
14 year={2026},
15 publisher={Elsevier}
16}