AudioScorer: Learning Question-Aware Token Relevance for Large Audio Language Models
Organizations: Institute of Signal Processing and System Theory (ISS), University of Stuttgart, Stuttgart, Germany
Abstract
Large Audio Language Models (LALMs) reason over speech, environmental sounds, music, and other acoustic information. However, their audio encoders produce dense token sequences that make long-form audio costly to process. Existing audio pruning methods reduce this cost using heuristics such as attention, representation similarity, or temporal sampling, but do not explicitly learn which tokens are most useful for a given question. We propose AudioScorer, a lightweight model that scores audio tokens according to the user question. It is trained by distilling the ranking of audio tokens under the frozen LALM's answer-gradient saliency, together with downstream answer supervision. Compared with other pruning methods, AudioScorer achieves the best or tied-best result at 10% token retention on 7 of 10 semantic and acoustic tasks, including speech recognition, emotion recognition, and audio-scene classification.
Figures & tables
| Speech Content | Audio Classification | Speaker Information | Audio | Prefill | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| auth. | compute | ||||||||||||||
| Keep | Method | ASR | SCR | SER | Avg. | SED | MC | ASC | Avg. | ER | SAR | SGR | Avg. | SD | TFLOPs |
| Unpruned | 97.68 | 82.81 | 24.02 | 68.17 | 70.18 | 100.00 | 70.31 | 80.16 | 33.82 | 15.53 | 99.63 | 49.66 | 90.11 | 46.04 | |
| FastV | 97.03 | 82.62 | 24.52 † | 68.06 | 69.82 | 100.00 | 70.62 † | 80.15 | 33.04 | 15.97 † | 98.98 | 49.33 | 87.53 | 35.83 | |
| SpeechPrune | 91.31 | 80.51 | 24.95 † | 65.59 | 68.59 | 100.00 | 70.22 | 79.60 | 35.14 † | 15.87 † | 98.90 | 49.97 † | 93.93 † | 35.93 | |
| DART | 95.93 | 82.87 † | 25.14 † | 67.98 | 69.84 | 100.00 | 70.50 † | 80.11 | 36.52 † | 15.90 † | 99.19 | 50.54 † | 93.09 † | 35.88 | |
| Method | |||
|---|---|---|---|
| Unpruned | 48.57 | 48.57 | 48.57 |
| FastV | 48.53 | 48.78 † | 47.17 |
| SpeechPrune | 48.14 | 47.86 | 46.01 |
| DART | 48.45 | 47.90 | 46.27 |
| Frame | 48.42 | 48.20 | 46.41 |
| HeadRouter | 48.64 † | 49.00 † | 46.16 |
| retention | retention | retention | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variant | SC | AC | SI | AA | SC | AC | SI | AA | SC | AC | SI | AA |
| AudioScorer (full) | 68.49 | 80.16 | 49.75 | 82.47 | 68.01 | 80.29 | 49.27 | 71.01 | 43.65 | 79.69 | 51.87 | 32.97 |
| w/o question conditioning | 68.13 | 79.95 | 49.55 | 81.06 | 68.48 | 80.31 | 49.67 | 64.76 | 41.84 | 80.26 | 51.22 | 31.36 |
| w/o relevance distillation | 67.90 | 79.93 | 49.70 | 38.92 | 63.04 | 80.30 | 50.04 | 35.64 | 27.72 | 73.12 | 48.41 | 44.03 |
| w/o both | 66.92 | 80.83 | 49.74 | 81.23 | 64.96 | 80.41 | 41.44 | 43.98 | 27.58 | 75.42 | 34.15 | 54.54 |
| w/o downstream CE | 68.33 | 80.38 | 49.53 | 84.13 | 68.29 | 80.69 | 49.01 | 79.64 | 31.20 | 74.02 | 51.71 | 51.06 |
Appendix figures & tables2 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | Speech | Sound | Music | Voice | Spatial | Multi | Open | Instr. | So–Mu | Mu–Sp | So–Sp | So–Mu–Sp | Avg. |
| 100% retention | |||||||||||||
| Unpruned | 46.80 | 41.07 | 55.36 | 42.76 | 46.15 | 38.37 | 3.210 | 37.93 | 42.00 | 36.96 | 32.95 | 57.14 | 48.57 |
| 70% retention | |||||||||||||
| FastV | 46.58 | 40.88 | 55.08 | 44.83 † | 45.85 | 37.91 | 3.210 | 39.08 † | 46.00 † | 36.96 | 32.95 | 57.14 | 48.53 |
| SpeechPrune | 45.45 | 42.41 † | 55.57 † | 39.31 | 43.69 | 35.35 | 3.220 † | 37.93 | 40.00 | 36.96 | 36.36 † | 57.14 | 48.14 |
| DART | 45.57 | 41.36 † | 55.57 † | 43.10 † | 44.62 | 37.91 | 3.247 † | 40.23 † | 42.00 | 36.96 | 29.55 | 71.43 † | 48.45 |
| Speech Content | Audio Classification | Speaker Information | Audio | ||||||||||
| auth. | |||||||||||||
| Variant | ASR | SCR | SER | Avg. | SED | MC | ASC | Avg. | ER | SAR | SGR | Avg. | SD |
| 70% retention | |||||||||||||
| AudioScorer (full) | 97.49 | 82.99 | 25.00 | 68.49 | 69.45 | 100.00 | 71.03 | 80.16 | 34.67 | 15.09 | 99.49 | 49.75 | 82.47 |
| w/o question-conditioning | 97.42 | 82.88 | 24.08 | 68.13 | 68.24 | 100.00 | 71.60 | 79.95 | 34.61 | 14.62 | 99.41 | 49.55 | 81.06 |
| w/o relevance distillation | 97.41 | 83.55 | 22.75 | 67.90 | 68.66 | 100.00 | 71.13 | 79.93 | 35.04 | 15.15 | 98.91 | 49.70 | 38.92 |
Token Pruning
Token pruning removes redundant tokens from transformer inputs or intermediate representations to reduce computation, memory use, and inference time.
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