Joint Fullband-Subband Modeling for High-Resolution SingFake Detection
Authors: Xuanjun Chen, Chia-Yu Hu, Sung-Feng Huang, Haibin Wu, Hung-yi Lee, Jyh-Shing Roger Jang
Organizations: Graduate Institute of Communication Engineering, National Taiwan University · Department of Computer Science and Information Engineering, National Taiwan University · NVIDIA Taiwan · Independent Researcher · NTU Artificial Intelligence Center of Research Excellence, National Taiwan University
Rapid advances in singing voice synthesis have increased unauthorized imitation risks, creating an urgent need for better Singing Voice Deepfake (SingFake) Detection, also known as SVDD. Unlike speech, singing contains complex pitch, wide dynamic range, and timbral variations. Conventional 16 kHz-sampled detectors prove inadequate, as they discard vital high-frequency information. This study presents the first systematic analysis of high-resolution (44.1 kHz sampling rate) audio for SVDD. We propose a joint fullband-subband modeling framework: the fullband captures global context, while subband-specific experts isolate fine-grained synthesis artifacts unevenly distributed across the spectrum. Experiments on the WildSVDD dataset demonstrate that high-frequency subbands provide essential complementary cues. Our framework significantly outperforms 16 kHz-sampled models, proving that high-resolution audio and strategic subband integration are critical for robust in-the-wild detection.
Figures & tables
Figure 1: Comparison of audio spectral coverage under different sampling rates. Existing systems typically process 16 kHz sampled audio, restricting them to the speech-critical band (0–8 kHz) and discarding high-frequency details. In contrast, our approach utilizes 44.1 kHz audio to cover the full spectral range (0–22.05 kHz). This preserves extended harmonics and breath textures essential for detecting sophisticated singing forgeries that are mathematically invisible at lower sampling rates.
Figure 2: The overview of our proposed Sing-HiResNet framework. The framework is implemented in two stages: Phase 1 establishes the backbone for fullband and subband expert models, while Phase 2 facilitates their integration through various joint fusion processes.
Model
Subband (kHz)
Valid
Test A
Test B
Fullband N=1
FB [0.0,22.0]
0.00–22.05
0.66
2.31
10.79
Subband N=2
SB [0.0,11.0]
0.00 – 11.03
1.39
2.81
22.01
SB [11.0,22.0]
11.03 – 22.05
1.71
5.66
15.32
SB-Concat-2
0.09
3.13
16.29
Table 1: EER (%) of subband expert models across different subband partition configurations. Model names indicate approximate frequency ranges for readability, while the subband (kHz) column reports the exact band boundaries. SB-Concat- N denotes the feature-level concatenation model combining all subbands in the same configuration.
Selected Model Pool P
Aggregation
Concatenation
Interaction
Distillation *
FB
SB L
SB M
SB H
Test A
Test B
Test A
Test B
Test A
Test B
Test A
Test B
Pool Pa
✓
✓
1.73
10.79
2.95
15.53
2.99
15.32
1.83
11.00
Pool Pb
✓
✓
2.56
11.21
2.95
20.82
3.24
16.29
3.13
12.19
Pool Pc
✓
✓
2.28
10.79
2.85
16.50
3.02
15.32
2.17
10.79
Pool Pd
✓
✓
✓
1.87
9.82
3.57
19.64
3.02
16.50
1.87
12.19
Pool Pe
✓
✓
✓
1.73
8.84
3.43
24.16
3.75
7.45
1.65
9.06
Table 2: EER (%) of the proposed integration framework across different component configurations.
Figure 3: EER (%) results across two categorization schemes. The left columns present a method-centric view to highlight frequency impact, while the right columns provide a condition-centric comparison of integration strategies across Test A and Test B.
Figure 4: Grad-CAM visualizations of expert and distilled models for bonafide and deepfake samples, featuring (a) single-teacher (Low) and (b) dual-teacher (Low/Mid-High) distillation. White dashed lines marking corresponding subband boundaries.
Notation
Description
Methods
Selected Model Pool P
EER (%)
FB D-LM
FB
SB L
SB M
Test A
Test B
(a)
FB D-LM
Pool Pe in Table 2
Distillation *
✓
✓
✓
1.65
9.06
(b)
FB A-LM
Pool Pe in Table 2
Aggregation
✓
✓
✓
1.73
8.84
(c)
FB SA-D-LM
Subband
Aggregation
✓
✓
✓
1.73
12.19
(d)
FB FSA-D-LM
Fullband-Subband
Aggregation
✓
✓
✓
✓
1.58
8.77
* FB is the fullband student model, SB ∼ are the subband expert teacher models.
Table 3: EER (%) of cross-integration strategies. SB L and SB M denote expert models for 0–11 kHz and 11–16.5 kHz bands, respectively.
Models
Backbone
fs
Test A (CI)
Test B (CI)
Baseline1
Wav2vec
16
6.09
24.09
Baseline2
Raw
16
8.84
26.11
PDL
Ensemble
16
5.80
22.01
NTU
SingGraph
16
4.31
31.82
IMS-SCU
WavLM
16
3.54
15.32
IMS-SCU
Ensemble
16
2.70
12.95
Table 4: Performance comparison on WildSVDD dataset, where fs denotes sampling rate (kHz). Results are presented in Equal Error Rate (EER, %) with 95% Confidence Intervals (CI).