Reinforcement Learning (RL) has become an effective paradigm for enhancing Large Language Models (LLMs) and visual generative models. However, its application in text-to-audio (TTA) generation remains largely under-explored. Prior work typically employs offline methods like Direct Preference Optimization (DPO) and leverages Contrastive Language-Audio Pretraining (CLAP) models as reward functions. In this study, we investigate the integration of online Group Relative Policy Optimization (GRPO) into TTA generation. We adapt the algorithm for Flow Matching-based audio models and demonstrate that online RL significantly outperforms its offline counterparts. Furthermore, we incorporate rewards derived from Large Audio Language Models (LALMs), which can provide fine-grained scoring signals that are better aligned with human perception. With only 470M parameters, our final model, Resonate, establishes a new SOTA on TTA-Bench in terms of both audio quality and semantic alignment.
Figures & tables
Figure 1: Left: the model architecture of Resonate. Right: The employed Flow-GRPO training paradigm.
Model
Params
NFE
Objective Metrics
Subjective Metrics
CE ↑
CU ↑
PC ↑
PQ ↑
CLAP ↑
AQAScore ↑
OVL
REL
AudioLDM-L-Full [ 1 ]
739M
200
3.275
5.137
3.219
5.854
0.441
0.574
-
-
AudioLDM-2-Large [ 31 ]
718M
200
3.441
5.440
2.957
5.984
0.415
0.589
-
-
Tango-Full [ 3 ]
866M
200
3.264
5.151
3.360
5.954
0.440
0.599
-
-
Tango-2-Full [ 9 ]
866M
200
3.468
5.196
3.800
5.895
0.467
0.702
-
-
MeanAudio-L-Full [ 10 ]
480M
25
3.304
5.151
2.995
5.743
0.469
0.729
-
-
Table 1: Evaluation results on the Accuracy subset of TTA-Bench
Models
LCC ↑
SRCC ↑
KTAU ↑
LAION-CLAP-630K-Best
0.472
0.477
0.337
Qwen2.5-Omni-7B
0.518
0.589
0.429
Qwen3-Omni-Instruct
0.575
0.586
0.429
Table 2: Correlation comparison on the the PAM dataset
Methods
CU ↑
PQ ↑
CLAP ↑
AQAScore ↑
Resonate-PT
5.238
5.923
0.458
0.651
w. DPO ( β=100 )
5.237
5.924
0.462
0.676
w. SFT
5.114
5.764
0.461
0.675
w. SFT + GRPO
5.184
5.883
0.472
0.728
\rowcolor blue!10 w. GRPO
5.328
6.064
0.476
0.737
Table 3: Ablation study on different training paradigms.
Methods
CU ↑
PQ ↑
CLAP ↑
AQAScore ↑
Resonate-PT
5.238
5.923
0.458
0.651
w. CLAPScore
5.276
6.063
0.479
0.711
\rowcolor blue!10 w. AQAScore
5.328
6.064
0.476
0.737
Table 4: Ablation study on different reward models.
Figure 2: Ablation study on Flow-GRPO configurations.