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| pretty_name: "PACC-P: Parallel Acoustic Confound Corpus, Presentation" | |
| language: | |
| - en | |
| size_categories: | |
| - 100K<n<1M | |
| task_categories: | |
| - audio-classification | |
| tags: | |
| - speech | |
| - noise | |
| - reverberation | |
| - bona-fide | |
| - robustness | |
| - anti-spoofing | |
| - parallel-corpus | |
| configs: | |
| - config_name: conditions | |
| data_files: condition_index.csv | |
| default: true | |
| - config_name: sources | |
| data_files: source_metadata.csv | |
| # PACC-P: Parallel Acoustic Confound Corpus, Presentation | |
| PACC-P is 5,992 bona fide speech clips under 50 presentation conditions: additive noise, | |
| babble and music at five SNRs, simulated rooms and echo, band limiting, pitch and tempo changes, | |
| pitch correction, and two compound cafe scenes passed through a codec. Every condition contains the | |
| same 5,992 clips as PACC-T, and every clip has a per-clip record logged at generation time. | |
| It contains no synthetic or spoofed speech. It is a reference for what the acoustic path between | |
| talker and microphone does to real speech: a bona fide baseline, a robustness benchmark and a | |
| condition-shift test set. | |
| | | | | |
| |---|---| | |
| | Conditions | 50 | | |
| | Clips per condition | 5,992 (same clips in every condition) | | |
| | Files | 299,600 FLAC, plus 5,992 sources in `pacc_base.tar` | | |
| | Duration | 356 h in total | | |
| | Size | 34.3 GB of audio; one condition 0.28-1.15 GB; sources 0.89 GB | | |
| | Download | per condition, so any subset can be fetched on its own | | |
| Companion dataset: **PACC-T** (Telecoms), the same 5,992 sources through 34 codecs, 12 tandem | |
| chains and 5 resample controls. doi:10.5281/zenodo.23026393 | |
| ## Before you measure | |
| ### SNR is set against the clean source's speech level | |
| Every SNR is relative to the ITU-T P.56 active speech level of the clean source clip. Noise level | |
| is the RMS over 20 ms frames within 40 dB of the loudest frame. Each mixed-in layer is scaled | |
| independently against the speech level. Speech is never rescaled on its own: if a finished mix | |
| would clip, the whole mix is scaled so its peak is 0.999 of full scale, and that gain is logged per | |
| clip (`safety_gain_db`). Achieved SNR is measured after mixing and logged. | |
| ### Duration changes break sample alignment | |
| `tempo_*` and `pitch_resample_*` change clip length. These conditions are parallel by clip, not by | |
| sample: align in time before any frame-by-frame comparison. All other conditions keep the source | |
| length. | |
| ### Band limiting and formants | |
| `bandpass_300_3400` and `lowpass_2400` remove content above 3.4 and 2.4 kHz. LPC formant trackers | |
| configured for wideband speech (Praat's default ceiling is 5500 Hz) fit spurious poles in the empty | |
| band, pulling F2 and F3 low with no error flag; on `lowpass_2400`, F3 is physically absent. Set the | |
| analysis ceiling from content bandwidth, or treat F2 and above as unreliable in these conditions. | |
| ### Cafe conditions are also codec conditions | |
| `cafe_voip` (Opus 16 kbps, 48 kHz) and `cafe_cellular` (AMR-WB 23.85 kbps, 16 kHz) mix three layers | |
| and then encode. To separate the scene from the codec, compare with `cafe_noise_snr15` and | |
| `music_instrumental_snr20` here, and with the matching codec and resample control in PACC-T. | |
| ### Native bandwidth differs by pool | |
| AMI sources are native 16 kHz (content to 8 kHz); VCTK sources are 48 kHz. Outputs keep the source | |
| rate except the cafe conditions. Compare within a pool, or account for this when pooling. | |
| ## Sources | |
| The same 5,992 source clips as PACC-T, shipped once in `pacc_base.tar` with per-source metadata. | |
| | Pool | Clips | Native format | Source corpus | | |
| |---|---|---|---| | |
| | AMI | 2,992 (4.45 h) | 16 kHz WAV, headset microphone | AMI Meeting Corpus: 139 meetings, 157 participants | | |
| | VCTK_mic1 | 1,500 (1.36 h) | 48 kHz FLAC | CSTR VCTK Corpus 0.92, mic1: 109 speakers | | |
| | VCTK_mic2 | 1,500 (1.36 h) | 48 kHz FLAC | CSTR VCTK Corpus 0.92, mic2: 108 speakers | | |
| VCTK mic pairing: 1,485 utterances appear in both mic pools; 15 in each pool are unpaired. Joining | |
| mic1 to mic2 on utterance ID gives 1,485 pairs, not 1,500. All sources are mono 16-bit PCM. | |
| AMI file IDs encode meeting, channel, segment index and start/end time in seconds. | |
| Per-source metadata ships as `sources/metadata.csv` in `pacc_base.tar`: speaker, gender and where | |
| the label came from, VCTK age and utterance, AMI meeting, channel, participant and segment times. | |
| ### Gender balance | |
| | Pool | Female | Male | Label source | | |
| |---|---|---|---| | |
| | VCTK_mic1 | 750 | 750 | VCTK speaker metadata | | |
| | VCTK_mic2 | 750 | 750 | VCTK speaker metadata | | |
| | AMI | 1,126 (38%) | 1,866 (62%) | AMI participant metadata | | |
| Sources were selected for gender balance. VCTK is balanced exactly. AMI is not: its clips were | |
| selected using gender inferred from the audio (pitch and apparent vocal-tract length), and those | |
| labels proved wrong for 17% of clips, mostly men labelled as women (441 clips, against 68 the other | |
| way). Checked against AMI's own participant metadata, the AMI pool is 62% male. The `gender` | |
| column gives the metadata label; the inferred label is kept, for transparency only, as | |
| `gender_inferred_not_recommended`. For TS meetings, which have no entry in AMI's | |
| `participants.xml`, sex is taken from the M/F prefix of the participant ID, which agrees with | |
| `participants.xml` for all 189 participants listed there. | |
| 8 AMI clips with no usable speech are excluded from all of PACC (`excluded_sources.csv`). Earlier | |
| internal builds also held RAVDESS and CREMA-D clips; they were removed so that PACC is CC BY only. | |
| ## Conditions | |
| | Condition | Family | Description | Output rate | Rate control | | |
| |---|---|---|---|---| | |
| | `babble_snr00` | babble | babble noise (6 talkers), 0 dB SNR | as source | - | | |
| | `babble_snr05` | babble | babble noise (6 talkers), 5 dB SNR | as source | - | | |
| | `babble_snr10` | babble | babble noise (6 talkers), 10 dB SNR | as source | - | | |
| | `babble_snr15` | babble | babble noise (6 talkers), 15 dB SNR | as source | - | | |
| | `babble_snr20` | babble | babble noise (6 talkers), 20 dB SNR | as source | - | | |
| | `env_noise_snr00` | scene | environment noise scene, 0 dB SNR | as source | - | | |
| | `env_noise_snr05` | scene | environment noise scene, 5 dB SNR | as source | - | | |
| | `env_noise_snr10` | scene | environment noise scene, 10 dB SNR | as source | - | | |
| | `env_noise_snr15` | scene | environment noise scene, 15 dB SNR | as source | - | | |
| | `env_noise_snr20` | scene | environment noise scene, 20 dB SNR | as source | - | | |
| | `music_instrumental_snr00` | music | instrumental music, 0 dB SNR | as source | - | | |
| | `music_instrumental_snr05` | music | instrumental music, 5 dB SNR | as source | - | | |
| | `music_instrumental_snr10` | music | instrumental music, 10 dB SNR | as source | - | | |
| | `music_instrumental_snr15` | music | instrumental music, 15 dB SNR | as source | - | | |
| | `music_instrumental_snr20` | music | instrumental music, 20 dB SNR | as source | - | | |
| | `music_vocal_snr00` | music | vocal music, 0 dB SNR | as source | - | | |
| | `music_vocal_snr05` | music | vocal music, 5 dB SNR | as source | - | | |
| | `music_vocal_snr10` | music | vocal music, 10 dB SNR | as source | - | | |
| | `music_vocal_snr15` | music | vocal music, 15 dB SNR | as source | - | | |
| | `music_vocal_snr20` | music | vocal music, 20 dB SNR | as source | - | | |
| | `white_noise_snr00` | white noise | white noise, 0 dB SNR | as source | - | | |
| | `white_noise_snr05` | white noise | white noise, 5 dB SNR | as source | - | | |
| | `white_noise_snr10` | white noise | white noise, 10 dB SNR | as source | - | | |
| | `white_noise_snr15` | white noise | white noise, 15 dB SNR | as source | - | | |
| | `white_noise_snr20` | white noise | white noise, 20 dB SNR | as source | - | | |
| | `reverb_small_rt030` | reverb | simulated room reverb (small), RT60 0.30 s | as source | - | | |
| | `reverb_medium_rt060` | reverb | simulated room reverb (medium), RT60 0.60 s | as source | - | | |
| | `reverb_large_rt100` | reverb | simulated room reverb (large), RT60 1.00 s | as source | - | | |
| | `echo_d150ms_m10db` | echo | single echo, 150 ms delay, -10 dB | as source | - | | |
| | `echo_d150ms_m20db` | echo | single echo, 150 ms delay, -20 dB | as source | - | | |
| | `echo_d300ms_m10db` | echo | single echo, 300 ms delay, -10 dB | as source | - | | |
| | `echo_d300ms_m20db` | echo | single echo, 300 ms delay, -20 dB | as source | - | | |
| | `bandpass_300_3400` | filter | bandpass filter, order 4, 300-3400 Hz | as source | - | | |
| | `lowpass_2400` | filter | lowpass filter, order 8, 2400 Hz | as source | - | | |
| | `pitch_psola_dn4` | pitch psola | pitch shift, PSOLA (duration kept), -4 semitones | as source | - | | |
| | `pitch_psola_dn2` | pitch psola | pitch shift, PSOLA (duration kept), -2 semitones | as source | - | | |
| | `pitch_psola_up2` | pitch psola | pitch shift, PSOLA (duration kept), +2 semitones | as source | - | | |
| | `pitch_psola_up4` | pitch psola | pitch shift, PSOLA (duration kept), +4 semitones | as source | - | | |
| | `pitch_resample_dn4` | pitch resample | pitch shift by resampling (duration changes), -4 semitones | as source | - | | |
| | `pitch_resample_dn2` | pitch resample | pitch shift by resampling (duration changes), -2 semitones | as source | - | | |
| | `pitch_resample_up2` | pitch resample | pitch shift by resampling (duration changes), +2 semitones | as source | - | | |
| | `pitch_resample_up4` | pitch resample | pitch shift by resampling (duration changes), +4 semitones | as source | - | | |
| | `autotune_hard` | autotune | pitch correction (autotune), retune 0 ms | as source | - | | |
| | `autotune_natural` | autotune | pitch correction (autotune), retune 50 ms | as source | - | | |
| | `tempo_080` | tempo | tempo change, pitch kept, x0.8 | as source | - | | |
| | `tempo_125` | tempo | tempo change, pitch kept, x1.25 | as source | - | | |
| | `tempo_150` | tempo | tempo change, pitch kept, x1.5 | as source | - | | |
| | `cafe_voip` | compound | cafe scene (babble 15 dB, cafe noise 15 dB, music 20 dB) then Opus 16 kbps | 48 kHz | PACC-T resample_ctrl_48k | | |
| | `cafe_cellular` | compound | cafe scene (babble 15 dB, cafe noise 15 dB, music 20 dB) then AMR-WB 23.85 kbps | 16 kHz | PACC-T resample_ctrl_16k | | |
| | `cafe_noise_snr15` | scene | cafe noise scene, 15 dB SNR | as source | - | | |
| ## How the material was made | |
| - **Rooms:** pyroomacoustics 0.10.1, image source plus ray tracing, air absorption, speaker to | |
| microphone 1.0 m at 1.5 m height, 4 layouts per room (one per clip, chosen by seed). Small | |
| 4.0 x 3.5 x 2.7 m (RT60 0.3 s), medium 7.0 x 5.0 x 3.0 m (0.6 s), large 12.0 x 9.0 x 4.0 m (1.0 s). | |
| The room impulse responses ship in `pacc-p_room_cache.tar`. Each reverb clip's params row names | |
| its room variant and the variant's `rir_sha256`; convolving the source with that response (recipe | |
| in the tarball's README) recreates the stored clip bit for bit. | |
| - **Babble:** 6 English talkers (3 female, 3 male) from MUSAN's LibriVox speech, each at its own | |
| position in the medium room. | |
| - **Scenes:** FSD50K clips, a continuous bed plus timed events at +6 dB relative to the bed. | |
| Cafe: tableware, pouring, footsteps, doors, light kitchen sounds, distant traffic, no voices, | |
| 0.4 events/s, in the medium room. Environment: home, office, street and in-car background, no | |
| voices, 0.3 events/s, no room. | |
| - **Music:** MUSAN music (CC BY and public-domain tracks only), played through a loudspeaker in the | |
| medium room. The cafe's music layer is drawn exactly like `music_instrumental_snr20`. | |
| - **Echo:** one copy delayed 150 or 300 ms at -10 or -20 dB. | |
| - **Filters:** Butterworth bandpass 300-3400 Hz (design order 4) and lowpass 2400 Hz (order 8). | |
| - **Pitch:** PSOLA keeps formants (Praat 6.1.38 via parselmouth 0.4.7, pitch 75-600 Hz); | |
| resampling moves formants with F0 (librosa 0.11.0, soxr_hq). Autotune snaps F0 to the nearest | |
| equal-tempered semitone (A4 = 440 Hz), retune 0 ms (hard) or 50 ms (natural). | |
| - **Tempo:** ffmpeg 8.1 `atempo`, pitch unchanged. | |
| - **Randomness:** every clip has its own seed, sha256 of `20260916|<condition>|<file_id>`, so every | |
| draw (noise clip, room layout, event timing) is reproducible. | |
| - **Software:** Python 3.11.9, numpy 1.24.4, scipy 1.15.3, soundfile 0.13.1, librosa 0.11.0, | |
| soxr 1.0.0, praat-parselmouth 0.4.7, pyroomacoustics 0.10.1, ffmpeg 8.1. | |
| ## Files | |
| | Tarball | Contents | | |
| |---|---| | |
| | `pacc_base.tar` | the 5,992 source clips (`sources/<pool>/`) and `sources/metadata.csv`, identical in PACC-T and PACC-P | | |
| | `pacc-p_<condition>.tar` | one condition: `pacc-p/<condition>/<pool>/<file_id>.flac`, `params.csv`, `README.txt`, and `attribution.csv` where third-party audio is mixed in | | |
| | `pacc-p_sample.tar` | 14 fixed sources (5 VCTK utterances on both mics, 4 AMI clips) through every condition | | |
| | `pacc-p_room_cache.tar` | the 24 simulated room variants (impulse responses, geometry, measured RT60/DRR) with recreation and hash recipes | | |
| All audio is 16-bit mono FLAC. `SHA256SUMS` and `TARBALL_INDEX.csv` list every tarball; | |
| `pacc-p_manifest.csv` lists every file with its sha256. Tarballs are deterministic. | |
| ## Per-clip records | |
| Each condition's `params.csv` has one row per clip, logged when the clip was generated: input and | |
| output sample rate and length, source speech level and peak, every target and achieved SNR, layer | |
| gains, safety gain, the near-floor flag, codec and codec length error for the cafe conditions. | |
| ## Known edge cases | |
| See `EDGE_CASES.txt`: the cafe conditions' combined-SNR tolerance (three clips deviate by more than | |
| 0.5 dB), rows near the 16-bit quantisation floor, inherited AMI clipping, and the excluded sources. | |
| ## Motivation | |
| The design of this corpus was motivated by Delgado et al. (ICASSP 2026), who argue that deepfake | |
| detection must account for how audio is presented through real communication channels, and by Lee | |
| et al. (ICASSP 2026), whose noise-aware multi-LoRA framework highlights real-world noise | |
| conditions. Neither group was involved in producing this dataset. | |
| - H. Delgado, G. Ramondetti, E. Dalmasso, G. Karvitsky, D. Colibro, H. Talib. "On Deepfake Voice | |
| Detection - It's All in the Presentation." ICASSP 2026. arXiv:2509.26471. | |
| - W. Lee, H. Dinh-Xuan, T.-P. Doan, S. Jung. "Dynamic Noise-Aware Multi LoRA Framework Towards | |
| Real-World Audio Deepfake Detection." ICASSP 2026. | |
| ## Licence and credits | |
| PACC-P is released under **CC BY 4.0** by Christopher Kleingertner (Moonscape Software). It is derived from: | |
| - **CSTR VCTK Corpus 0.92.** J. Yamagishi, C. Veaux, K. MacDonald. University of Edinburgh, CSTR, | |
| 2019. doi:10.7488/ds/2645. CC BY 4.0. | |
| - **AMI Meeting Corpus.** University of Edinburgh et al. https://groups.inf.ed.ac.uk/ami/corpus/. | |
| CC BY 4.0. J. Carletta (2006), "Announcing the AMI Meeting Corpus", ELRA Newsletter 11(1). | |
| - **MUSAN.** D. Snyder, G. Chen, D. Povey (2015), arXiv:1510.08484. https://www.openslr.org/17/. | |
| CC BY 4.0; only CC BY and public-domain files used. | |
| - **FSD50K.** E. Fonseca et al. (2022), IEEE/ACM TASLP 30. doi:10.5281/zenodo.4060432. CC BY; only | |
| CC0 and CC BY clips used. | |
| Third-party clips keep their own licences; per-clip credits are in `attribution.csv` (4,696 clips: | |
| CC0, CC BY 3.0/4.0 and public domain). Please credit these sources alongside PACC-P. | |
| ## Citation | |
| ```bibtex | |
| @dataset{moonscape_pacc_p_2026, | |
| author = {Kleingertner, Christopher and {Moonscape Software}}, | |
| title = {{PACC-P: Parallel Acoustic Confound Corpus, Presentation}}, | |
| year = {2026}, | |
| version = {1.0}, | |
| publisher = {Zenodo}, | |
| doi = {10.5281/zenodo.23026395} | |
| } | |
| ``` | |