From Voiceprints to User Entities: Online Speaker-Memory Construction for Multi-User Spoken Agents
Authors: Yucong Zhang, Cancan Li, Bo Xiao, Ke Zeng, Ming Li
Organizations: School of Computer Science, Wuhan University · School of Artificial Intelligence, The Chinese University of Hong Kong, Shenzhen · Meituan
Personalized spoken agents must identify speakers before accessing user-specific memory, yet memory benchmarks typically assume correctly attributed histories. We argue that voiceprints are observations of identity, not identities themselves, and formulate online speaker-memory construction to maintain persistent user entities as acoustic evidence evolves. We introduce EvoSpeakerMem, a training-free layer for causal speaker routing, selective acoustic-state updates, and identity-partitioned memory writes and retrieval through a replaceable text-memory backend. We also construct LoCoMo-ID, a spoken-memory benchmark with hidden speaker identities, speaker-sensitive queries, simulated recording-condition shifts, and four-speaker identity-confusion tests. On longitudinal SMIIP-TV, genuine-probe rejection under a frozen near-enrollment threshold rises from 29.8% to 55.6% over approximately one year. On LoCoMo-ID speaker-sensitive queries, gated updating improves identity-gated QA over fixed representations by 3.86 and 11.62 percentage points under clean and shifted conditions, respectively, with no wrong-user authorizations. The advantage persists in the four-speaker test. Yet reducing fragmentation and improving QA can coexist with incorrect cross-user links, revealing a fragmentation--contamination trade-off that QA alone cannot capture.
Figures & tables
Figure 1: Overview of EvoSpeakerMem as a speech support layer for replaceable textual-memory backends. Acoustic routing assigns each turn to a persistent user entity before its content is written to memory.
Condition
Acoustic evidence
Metric
Fixed
Update
Gated update
All-exemplar KNN
Clean
ECAPA-only
FB3↑
97.04
98.41
99.54
98.51
FNUR ↓
0.77
0.27
0.31
0.21
Clusters/Gold
3.217
1.767
1.883
1.583
ECAPA + diarization
FB3↑
76.96
77.06
77.06
77.09
FNUR ↓
0.08
0.07
0.07
0.07
Clusters/Gold
1.150
1.117
1.117
1.117
Table 1: Online speaker-memory construction results on LoCoMo-ID clean speech and recording-shifted condition. Acoustic evidence distinguishes ECAPA-only routing from routing augmented with session-level diarization. We report partition quality ( FB3 ) and fragmentation-related indicators (FNUR and Clusters/Gold). All rates are percentages except Clusters/Gold.
Gap (days)
EER
Below- τ
Imp. accept
Gen. sim.
0–1 days
9.7
29.8
2.0
0.538
60–100 days
11.2
40.7
1.8
0.495
365–450 days
14.0
55.6
1.4
0.446
Table 2: Fixed-template verification across SMIIP-TV time gaps. Error rates are percentages. “Imp. accept” is the proportion of impostor trials exceeding the frozen threshold; “Gen. sim.” is mean genuine cosine similarity.
Acoustic evidence / policy
Clean
Condition-shifted
ECAPA / Fixed
72.31
69.27
ECAPA / Update
73.30
72.55
ECAPA / Gated update
73.38
72.04
ECAPA / All-exemplar KNN
73.38
72.79
Parakeet+ECAPA / Fixed
73.43
72.96
Parakeet+ECAPA / Update
73.50
73.16
Table 3: Matched all-memory QA (%) for eight policies at merge threshold 0.489. Results are micro-pooled judge-correct answers over speaker-sensitive queries without query-speaker filtering or privacy denial.
Condition
ECAPA policy
C/W/D
QA
QA ∣ Correct
Clean
Fixed
4084/0/29
71.41
71.91
Update
3993/115/5
73.43
75.63
Gated update
4110/0/3
75.27
75.33
KNN
3993/116/4
73.64
75.86
Condition-shifted
Fixed
4079/1/33
60.15
60.65
Update
3993/115/5
70.24
72.35
Table 4: Top-1 private-access results on 4,113 speaker-sensitive query audios under clean and shifted condition. C/W/D denotes correct, wrong, and denied authorizations; QA requires correct authorization and a judge-correct answer (%). KNN denotes All-exemplar KNN.
Acoustic evidence / policy
Online ID
FB3
C / W / D
Targeted QA ( n=19 )
Full QA ( n=1,371 )
ECAPA / Fixed
98.84
96.54
1342 / 18 / 11
78.95
67.83
ECAPA / Update
93.35
95.45
1335 / 32 / 4
78.95
72.06
ECAPA / Gated update
96.25
97.77
1368 / 0 / 3
78.95
73.60
ECAPA / All-exemplar KNN
94.85
97.20
1335 / 33 / 3
78.95
71.99
Parakeet+ECAPA / Fixed
74.03
72.86
1335 / 32 / 4
68.42
71.48
Parakeet+ECAPA / Update
71.96
72.57
1333 / 32 / 6
73.68
72.28
Table 5: Four-speaker interleaved stress test: ten clean collections, 11,764 history turns, and 40 gold speakers. Online ID excludes missing predictions. C/W/D counts correct/wrong/denied authorizations on 1,371 queries. Both QA columns require correct authorization and a judge-correct answer; targeted QA uses 19 gated items among 20 diagnostics. Rates are percentages. This differs from the standard 4,113-query condition.
Appendix figures & tables23 assets
Supplementary material from the paper’s appendix.
Appendix
Model
SR
SV
Qwen2.5-Omni Xu et al. (2025a)
19.00
24.00
AudioFlamingo-3 Goel et al. (2025)
23.00
29.00
Qwen3-Omni Xu et al. (2025b)
49.00
40.00
Kimi-Audio KimiTeam et al. (2025)
46.00
24.00
StepAudio2 Wu et al. (2025a)
34.00
43.00
MiMoAudio Xiaomi LLM-Core Team et al. (2025)
38.00
48.00
Appendix
Table 6: MSU-Bench speaker retrieval (SR) and verification (SV) accuracy (%). Unified speaker state uses deterministic tool readout.
0–1 days
60–100 days
365–450 days
Encoder
EER
Below- τ
EER
Below- τ
EER
Below- τ
ECAPA-TDNN
9.71
29.82
11.18
40.70
14.09
55.54
ReDimNet2-B6
3.34
5.19
4.82
8.78
6.35
12.96
Appendix
Table 7: Matched-set fixed-template verification at representative enrollment–probe gaps. EER and Below- τ are percentages. The comparison uses the 205,765 text-independent utterances successfully processed by both encoders, with identical enrollment utterances, genuine probes, impostor trials, and time buckets. Each encoder uses its own threshold frozen after near-enrollment calibration at target FAR=2% ( τECAPA=0.4752 ; τReDimNet2=0.6131 ), so threshold values are not compared directly. ReDimNet2-B6 lowers absolute error, but both encoders exhibit higher EER and a larger below-threshold genuine rate at longer gaps.
Figure 2: Matched-set short-term fixed-template verification for ECAPA and ReDimNet2-B6. Both encoders use identical utterances and time buckets, while each uses an encoder-specific threshold frozen after near-enrollment FAR=2% calibration. ReDimNet2-B6 lowers absolute EER and below-threshold genuine rate, but both measures increase as the enrollment–probe gap grows.
Figure 3: Matched-set long-term fixed-template verification for ECAPA and ReDimNet2-B6, including the approximately one-year follow-up. Although ReDimNet2-B6 substantially improves absolute separability, its EER and below-threshold genuine rate still worsen at longer enrollment–probe gaps.
ECAPA-TDNN
ReDimNet2-B6
Large-span condition
FB3↑
FNUR ↓
Frag. ↓
FB3↑
FNUR ↓
Frag. ↓
Intra-day TOD
63.08
18.09
25.52
62.91
6.75
12.33
Inter-day
66.58
1.21
12.20
70.56
0.22
3.08
Long-term cross-batch
67.60
3.60
20.79
81.49
0.91
4.51
Environment
67.05
5.00
23.53
73.43
1.16
7.84
Speaker state
58.88
6.78
27.63
66.90
1.14
11.45
Appendix
Table 8: Matched-session large-span causal replay for the all-exemplar KNN policy. ECAPA-TDNN and ReDimNet2-B6 replay identical common-utterance session streams under encoder-specific thresholds calibrated with the same near-enrollment FAR=2% protocol. Frag. denotes speaker fragmentation (%). ReDimNet2-B6 improves absolute online entity maintenance in most conditions, particularly for long-term and context-variable replay; the near-equal intra-day B 3 F1 should be interpreted together with its lower FNUR and fragmentation.
Figure 4: Fixed-template verification over the full observed time range. The same low-drift-calibrated threshold is frozen for all buckets; the final bucket uses the approximately one-year follow-up collection.
Figure 5: Below- τ and EER across time gaps in the unrestricted data and in the controlled observational subset. The controlled comparison reduces several measured context differences but does not establish a causal effect of time.
Figure 6: Speaker-level Below- τ in the nearest and farthest within-release time buckets. Lines connect observations from the same speaker where both buckets are available.
Figure 7: Fixed-template Below- τ and EER across recording environment, speaker state, and time of day. Probes are within 14 days of enrollment, and displayed categories contain at least 300 probes. Complete category breakdowns follow below.
Figure 8: Complete near-enrollment breakdown by recording environment. Sample sizes are shown in the plot; categories with small support should be interpreted cautiously.
Figure 9: Complete near-enrollment breakdown by reported speaker state. Lower Below- τ in a category does not necessarily imply uniformly easier routing because impostor acceptance (shown as FMR in the figure) and sample support can differ.
Figure 10: Complete near-enrollment breakdown by time of day. All five periods have broad speaker coverage, but the comparison remains observational.
Dimension
Small span (control)
Large span (higher drift)
Purpose
Intra-day TOD
Same day and same time-of-day bucket as enrollment
Same day, at least two time-of-day buckets from enrollment
Isolate within-day change
Inter-day
0–3 days after enrollment
30–100 days after enrollment
Short-term temporal drift
Long-term cross-batch
Same-release SMIIP-TV probe
Follow-up probe approximately one year later
Long-term return
Environment
Within 14 days, same environment as enrollment
Within 14 days, different environment
Approximate environment contrast
Speaker state
Within 14 days, normal state
Within 14 days, non-normal state (e.g., sleepy, eating, hoarse, or exercise)
Approximate state contrast
Long-term × hist.-env.
Follow-up probes from speakers with low historical environment entropy
Follow-up probes from speakers with high historical environment entropy
Long-term return by prior variability
Appendix
Table 9: Small- and large-span definitions for the six SMIIP-TV online replay dimensions. Hist.-env. uses variability in the original SMIIP-TV histories.
Policy
Pcreate↑
Rcreate↑
Plink↑
Rknown↑
FB3↑
First exemplar
21.77
52.90
66.25
62.90
46.82
Enrollment mean
27.23
42.83
57.18
56.51
53.58
Latest exemplar
23.95
54.14
34.60
33.10
32.20
Online mean
31.24
38.48
46.54
46.65
55.99
EMA
31.07
42.01
41.36
41.35
52.03
All-exemplar KNN
31.06
56.24
52.56
51.30
65.31
Appendix
Table 10: Macro-averaged large-span decision and B 3 results across six SMIIP-TV conditions (five seeds; %; higher is better).
Figure 11: Large-span B 3 F1 (%), averaged over five seeds. Bold marks the best policy per condition. TOD denotes time of day; Hist.-env. denotes historical environment variability.
Figure 12: Large-span CREATE/LINK decision metrics across six policies and six conditions (five-seed means; %; higher is better).
Acoustic evidence / policy
Clean
Condition-shifted
ECAPA / Fixed
65.53
61.09
ECAPA / Update
66.63
65.54
ECAPA / Gated update
66.87
64.99
ECAPA / All-exemplar KNN
66.65
66.25
Parakeet+ECAPA / Fixed
66.30
65.36
Parakeet+ECAPA / Update
65.93
65.74
Appendix
Table 11: Full-set all-memory QA (%) for eight policies on clean and condition-shifted speech. Each condition comprises 30 collections and 5,958 query audios. Scores are micro-pooled judge-correct rates without speaker-based retrieval filtering.
Condition
Acoustic evidence / policy
Turns
Entities
Pcreate
Rcreate
Plink
Rknown
FNUR
Clean
ECAPA / Fixed
17643
193
30.05
96.67
99.98
99.22
0.77
ECAPA / Update
17643
106
54.72
96.67
97.49
97.23
0.27
ECAPA / Gated update
17643
113
51.33
96.67
99.95
99.65
0.31
ECAPA / All-exemplar KNN
17643
95
61.05
96.67
97.48
97.29
0.21
Parakeet+ECAPA / Fixed
17644
69
79.71
91.67
81.41
81.36
0.08
Parakeet+ECAPA / Update
17644
67
82.09
91.67
81.40
81.37
0.07
Appendix
Table 12: History turn-micro causal routing results for all eight policies under clean speech and condition shifted at merge threshold 0.489. Values are percentages except Turns and Entities.
Condition
Acoustic evidence / policy
C
W
D
Safe auth.
QA
QA ∣ Correct
Clean
ECAPA / Fixed
4084
0
29
99.29
71.41
71.91
ECAPA / Update
3993
115
5
97.08
73.43
75.63
ECAPA / Gated update
4110
0
3
99.93
75.27
75.33
ECAPA / All-exemplar KNN
3993
116
4
97.08
73.64
75.86
Parakeet+ECAPA / Fixed
3833
273
7
93.19
68.08
73.05
Parakeet+ECAPA / Update
3833
272
8
93.19
68.25
73.23
Appendix
Table 13: Speaker-sensitive Top-1 authorization and end-to-end answer utility over 4,113 questions per condition (clean and condition-shifted). C/W/D are counts, other values are percentages.
Policy
Online ID
FB3
C / W / D
Targeted strict (19)
Targeted raw (20)
Full strict (1,371)
QA ∣ Correct
ECAPA
Fixed
98.84
96.54
1342/18/11
15/19 (78.95)
15/20 (75.00)
930/1371 (67.83)
69.30
Update
93.35
95.45
1335/32/4
15/19 (78.95)
16/20 (80.00)
988/1371 (72.06)
74.01
Gated update
96.25
97.77
1368/0/3
15/19 (78.95)
15/20 (75.00)
1009/1371 (73.60)
73.76
KNN
94.85
97.20
1335/33/3
15/19 (78.95)
16/20 (80.00)
987/1371 (71.99)
73.93
Parakeet+ECAPA
Appendix
Table 14: Complete four-speaker results on ten clean collections. Targeted strict QA (19) and full strict QA (1,371) require correct authorization and a judge-correct answer; targeted raw judge (20) requires only a judge-correct answer and includes the non-gated item. C/W/D are full-set authorization counts. QA ∣ Correct conditions full strict QA on C. All rates are percentages; KNN denotes All-exemplar KNN.
τupdate
Entities
Online (%)
B 3 F1 (%)
Query assigned / 5958
W / 4113
QA (%)
0.50
106
97.23
98.41
5953
115
73.33
0.54
110
98.65
99.11
5954
32
74.81
0.58
113
99.64
99.54
5955
0
75.27
0.62
114
99.64
99.54
5955
0
75.27
0.66
114
99.64
99.55
5955
0
75.47
0.70
118
99.61
99.45
5955
0
75.44
Appendix
Table 15: Clean ECAPA gated-update sweep, fixed merge threshold 0.489. Routing/cluster scores and query assigned are from the upstream replay; W and QA are from the separate complete downstream threshold-sweep runs, not the default-run main table.
Condition
ECAPA policy
<1 s: correct / n
1 – <2 s: correct / n
≥2 s: correct / n
Clean
Gated update
48 / 59 (81.36%)
375 / 382 (98.17%)
17157 / 17202 (99.74%)
All-exemplar KNN
50 / 59 (84.75%)
372 / 382 (97.38%)
16742 / 17202 (97.33%)
Condition-shifted
Gated update
2 / 13 (15.38%)
195 / 252 (77.38%)
17223 / 17379 (99.10%)
All-exemplar KNN
3 / 13 (23.08%)
210 / 252 (83.33%)
16894 / 17379 (97.21%)
Appendix
Table 16: Post-hoc duration-bucket first-seen-binding accuracy on evaluated history turns. Each policy/condition denominator sums to 17,643 (clean) or 17,644 (condition-shifted); the short bins are very small in the augmented condition.
Stage
Model
Decoding configuration
History and query transcription
Qwen3-Omni-30B-A3B-Instruct
Sampling: temperature 0.7, top- p 0.8, top- k 20; maximum 512 new tokens.
LightMem factual extraction
Qwen3-Omni-30B-A3B-Instruct
Sampling: temperature 0.1, top- p 0.1; maximum 16,000 new tokens. The configured top- k=1 is not forwarded to the decoder.
Answer generation
Qwen3-Omni-30B-A3B-Instruct
Greedy decoding ( do_sample=False ); maximum 300 new tokens.
LLM-as-a-judge
Qwen3-Omni-30B-A3B-Instruct
Greedy decoding ( do_sample=False ); maximum 200 new tokens.
Text embedding
bge-small-en-v1.5
384-dimensional embedding; no generative decoding.
Appendix
Table 17: Models and generation settings for the reported LoCoMo-ID experiments.
Conversational memory equips AI assistants to retain, update, and retrieve useful information from past interactions for coherent, personalized dialogue.
Multi-user voice agents must track who said what across dialogue sessions. Text LLMs are attractive backbones for such agents, but transcripts alone do not expose acoustic speaker identity, leaving the model without a persistent reference for linking information to speakers across sessions. We address this gap by introducing Speaker Handles, soft-token representations that expose acoustic speaker identity to a frozen text LLM for cross-session speaker-dependent reasoning. A three-stage curriculum trains a lightweight projector, with fewer than 0.1% of the backbone's parameters, to map speaker embeddings into these handles. Establishing whether the resulting handles truly support cross-session speaker-dependent reasoning is challenging with existing benchmarks because textual cues can partially reveal fact ownership. We therefore present SpeakerBind, a controlled shared-agent benchmark in which overlapping facts across users require correct cross-session speaker attribution. Speaker Handles achieve 97.40-98.36% accuracy on VoxCeleb1 and 70.40% on SpeakerBind, close to the 71.88% topline. These results show that the proposed Speaker Handles provide an efficient way to integrate acoustic speaker identity into frozen text LLMs for speaker-content reasoning.
Runqiu Xu, Zhisheng Zheng, David Harwath
The University of Texas at Austin, Austin, TX, USA
Modern voice assistants may be shared by multiple users and should be able to answer questions about earlier conversations such as "When did I originally plan to leave?" or adapt their behavior to individual users based on past interactions. This requires more than retrieving a topically similar passage: the assistant must identify the current speaker, recover the relevant past state, and distinguish it from later revisions. We present PERSIST, a persistent memory system for multi-session, multi-speaker spoken dialogue that explicitly models Who, What, and When. PERSIST structures cross-session histories into readable event records and retrieves them with a 3W joint scoring mechanism that combines semantic content, acoustic speaker identity, and temporal state. For real-time full-duplex interaction, PERSIST further reuses intermediate representations from the dialogue backbone, avoiding query-audio re-encoding and reducing retrieval latency from 578.42 ms to 7.03 ms. We also introduce SpokenTrace, a diagnostic benchmark that factorizes evaluation along memory tasks and speaker-query types, exposing failures in recall, speaker attribution, and temporal-state tracking. On SpokenTrace, PERSIST achieves 85.08% end-to-end task accuracy and improves all-support EM@3 from 49.01% with BGE-large to 82.10%.
Long-term memory enables agents to accumulate information and reason across sessions, yet existing research primarily focuses on dyadic text or image-text conversations, leaving long-term memory for multi-party spoken conversations underexplored. This setting requires preserving conversational content, identifying participants across sessions, and retaining who speaks to whom. To this end, we propose VoxPolyMem, an interaction-aware multimodal memory framework combining incremental speaker identification with a memory hierarchy comprising interaction memory, fact memory, and participant profiles. We formulate retrieval as sequential decision-making, where an agent rewrites queries and selects retrieval tools and memory layers based on accumulated evidence to address information gaps. We further introduce Evidence-Gain GRPO (EG-GRPO), which uses round-wise credit assignment to encourage complementary evidence acquisition. We also construct VoxPolyBench to evaluate memory evolution, personalized answering, memory retrieval and reasoning, and interaction reasoning and attribution in multi-party spoken conversations. VoxPolyMem achieves an overall score of 85.0 on VoxPolyBench, surpassing the strongest evaluated baseline by 23.6 points. On Mem-Gallery and H2HMem-Multi, it scores 89.6 and 74.4, respectively, exceeding the strongest evaluated public memory baselines by over 8 points each. These results highlight its potential for persistent, personalized assistance in multi-party multimodal interactions. Code and datasets are available at https://voxpolymem.github.io/VoxPolyBench/demo/