Evaluating 'anime-like' voices currently relies on costly subjective judgments, yet no standardized objective metric exists. A key challenge is that anime-likeness, unlike naturalness, lacks a shared absolute scale, making conventional Mean Opinion Score (MOS) protocols unreliable. To address this gap, we propose AnimeScore, a preference-based framework for automatic anime-likeness evaluation via pairwise ranking. We collect 15,000 pairwise judgments from 187 evaluators with free-form descriptions, and acoustic analysis reveals that perceived anime-likeness is driven by controlled resonance shaping, prosodic continuity, and deliberate articulation rather than simple heuristics such as high pitch. We show that handcrafted acoustic features reach a 69.3% AUC ceiling, while SSL-based ranking models achieve up to 90.8% AUC, providing a practical metric that can also serve as a reward signal for preference-based optimization of generative speech models.
Figures & tables
Corpus
Train
Test
Total
Anim-400k [ 20 ]
1,065
250
1,315
ReazonSpeech [ 21 ]
828
120
948
Coco-Nut [ 22 ]
607
130
737
Total
2,500
500
3,000
Table 1: Statistics of speech samples for subjective evaluation
Category
Group
Count
Age
20s or younger
8
30s
48
40s
80
50s or older
51
Gender
Male
142
Female
45
Table 2: Demographics of participants ( n=187 )
Figure 1: Corpus-wise distribution of empirical win rate for (a) train and (b) test data.
Figure 2: Visualizations of acoustic proxies for anime-likeness speech. (a) F1-F2 formant space distribution comparing high-win rate (top 25%) and low-win rate (bottom 25%) utterances. (b) Split violin plots of normalized spectral flux and voicing ratio distributions for the top and bottom 25% groups. (c) Overall syllable rate and articulation rate across win rate.
Category
Count
Emotional Explicitness
62
Timbre Difference
48
Prosodic Salience
38
Articulation Clarity
34
Temporal Control
5
Table 3: Distribution of Annotator-Identified Key Features of Anime-Like Speech ( n=187 )
Dimension
Proxy Metrics
PCR (%)
Emotional Explicitness
Intensity (Arousal)
52.2 ( ↑ )
Timbre Difference
F1 median (Hz)
59.6 ( ↓ )
F2 median (Hz)
61.5 ( ↓ )
F3 median (Hz)
60.1 ( ↓ )
Prosodic Salience
Mean F0 (Hz)
55.1 ( ↓ )
Voicing ratio
59.5 ( ↑ )
Table 4: Pairwise Concordance Rate (PCR) between acoustic proxies and subjective anime-likeness. ↑ / ↓ : the preferred utterance tends to have a higher/lower value. †
Figure 3: Architecture of an anime score prediction model
Feature Set
#Feat.
Acc. (%)
AUC (%)
Emot. Explicit.
1
52.1 ± 0.6
52.9 ± 0.9
Timbre Diff.
3
60.0 ± 1.3
65.7 ± 1.4
Prosodic Sal.
3
62.0 ± 1.2
66.0 ± 1.5
Artic. Clarity
4
59.8 ± 1.3
66.8 ± 1.4
All Combined
11
63.4 ± 1.2
69.3 ± 1.5
Table 5: Multivariate pairwise prediction via logistic regression on acoustic feature differences (5-fold CV, N=15,000 pairs).
Backbone
NLL
Acc.(%)
AUC(%)
wav2vec2 [ 5 ]
0.5139
0.7430
0.8247
WavLM [ 6 ]
0.4284
0.8105
0.8944
HuBERT [ 27 ]
0.3852
0.8243
0.9082
data2vec [ 28 ]
0.4686
0.7709
0.8580
Table 6: Ablation study on SSL backbones for anime-likeness preference prediction (pairwise test set, N=2500 ).
Automated Text-to-Speech (TTS) evaluation methods (Mean Opinion Score (MOS) predictors and Audio Large Language Model (Audio-LLM) judges) are expected to reflect human perception, yet it is unclear how well they capture the distinct aspects of speech that listeners actually perceive. We deconstruct "naturalness" into a linguistically grounded annotation schema spanning 10 distinct perceptual dimensions, and use it to construct the first dimension-level meta-evaluation benchmark for TTS, comprising 860 utterances annotated by trained linguist raters. Results from benchmarking four MOS predictors and four Audio-LLM judges reveal that MOS predictors are more sensitive to acoustic signal-level properties at the prosodic and paralinguistic levels, while Audio-LLM judges show selective, prompt-dependent detection that favors word-level errors and does not generalize across all dimensions. Neither class reliably captures a breadth of linguistically structured, human-perceptible speech errors. Our dataset, annotation schema, and evaluation code are publicly released to support more targeted and interpretable TTS evaluation.
Popular ASR test sets adopt inconsistent conventions for numbers, disfluencies, entities, and casing, while standard normalizers erase the format distinctions users care about. Current benchmarks therefore cannot measure whether a model follows user preferences for output style. We introduce PreferenceASR, a test set evaluating ASR systems on their ability to follow natural-language preference instructions across four categories: normalization, entities, disfluencies, and case. Built from seven open-source corpora via a two-stage LLM-assisted pipeline with human verification, it is evaluated with a preference-aware normalizer that selectively skips steps matching the active instruction. Benchmarking four models shows rankings shift across preference types, exposing quality differences traditional evaluation obscures. We publicly release the dataset.
Nithin Rao Koluguri, Sasha Meister, Nikolay Karpov +4
Large Audio-Language Models (LALMs) have been widely used as judge models for the automatic evaluation of generated speech. However, prior approaches predominantly focus on holistic naturalness, leaving fine-grained paralinguistic distinctions underexplored. We introduce ParaPairAudioBench, a pairwise benchmark of 5,175 audio pairs across five paralinguistic dimensions: Style, Rate, Emphasis, Age, and Gender. Our experiments show that current LALM judges still lag behind human judgments by 32%p on average and exhibit severe calibration failures, particularly in Tie cases where the correct decision is to abstain. To further analyze lexical versus acoustic reliance, the benchmark includes both same-transcript and cross-transcript conditions. ParaPairAudioBench enables multi-dimensional, calibration-aware assessment of the reliability of LALM-as-a-Judge for paralinguistic speech evaluation.
Jisu Jeon, Seungyeon Jwa, Joosung Lee +6
Hongik University, South Korea · Seoul National University, South Korea · NAVER Cloud, South Korea +1