{ "test_date": "2026-09-09", "scope": "One iPhone, one built-in microphone route in measurement mode, one speaker setup, one session; sequential NIOSH and Lullasure passes.", "status": "Offline correction analysis of recorded values; corrected-app confirmation measurements have not been recorded.", "metric": "A-weighted Slow current level. Difference = Lullasure + correction - NIOSH; positive means Lullasure is higher.", "source_audit": { "all_18_pairs_match_both_sources": true, "missing_pairs": 0, "interpolated_values": 0 }, "counts": { "total": 18, "included_fit": 11, "same_session_held_out_sounds": 3, "repeats": 2, "excluded_background": 1, "excluded_lowest_250_hz_tone": 1, "included_total": 16 }, "correction": { "method": "Arithmetic mean of NIOSH minus Lullasure on 11 included fit cases only; single additive least-squares correction.", "exact_additive_db": 22.990054545454544, "rounded_additive_db": 23.0, "original_development_offset_db": 94, "provisional_offset_db": 117, "exact_vs_rounded_difference_db": 0.00994545454545559, "frequency_or_level_dependent_correction_fitted": false }, "scoring": { "niosh": "Median of three visually verified large live A/Slow displayed values per case; these may include repeated UI values.", "lullasure": "One actual 1 Hz exported sample in the original last-1.8-second guarded scoring window; no interpolation.", "exclusion": "Background is not a stimulus fit case. Apply the pre-existing protocol background-screening heuristic (roughly 10 dB above measured background) in both passes; only the lowest 250 Hz tone fails. This was a protocol heuristic, not a formal preregistered study.", "low_tone_reference_margin_db": 5.600000000000001, "low_tone_lullasure_margin_db": 7.0344000000000015, "held_out_scope": "White noise, brown noise, and a multitone were reserved in the stimulus manifest and did not affect the fitted correction. They share the same session, phone, room, and source; they are not independent validation." }, "included_reference_range_dba": [ 47.8, 70.8 ], "metrics": { "fit": { "original": { "count": 11, "mean_error_db": -22.990054545454544, "rmse_db": 22.997575273533037, "max_absolute_error_db": 24.0213, "mean_absolute_error_db": 22.990054545454544 }, "exact_fit_offline": { "count": 11, "mean_error_db": -6.459479416000911e-16, "rmse_db": 0.5880990212906111, "max_absolute_error_db": 1.0312454545454557, "mean_absolute_error_db": 0.49957851239669343 }, "rounded_correction_offline": { "count": 11, "mean_error_db": 0.009945454545455267, "rmse_db": 0.5881831100168485, "max_absolute_error_db": 1.0213000000000036, "mean_absolute_error_db": 0.5022909090909102 } }, "holdout": { "original": { "count": 3, "mean_error_db": -22.475166666666667, "rmse_db": 22.47806129562779, "max_absolute_error_db": 22.895300000000002, "mean_absolute_error_db": 22.475166666666667 }, "exact_fit_offline": { "count": 3, "mean_error_db": 0.5148878787878791, "rmse_db": 0.6286751492450132, "max_absolute_error_db": 0.9755545454545498, "mean_absolute_error_db": 0.5148878787878791 }, "rounded_correction_offline": { "count": 3, "mean_error_db": 0.5248333333333335, "rmse_db": 0.6368460907733782, "max_absolute_error_db": 0.9855000000000018, "mean_absolute_error_db": 0.5248333333333335 } }, "repeat": { "original": { "count": 2, "mean_error_db": -23.012000000000004, "rmse_db": 23.01212027084858, "max_absolute_error_db": 23.086400000000005, "mean_absolute_error_db": 23.012000000000004 }, "exact_fit_offline": { "count": 2, "mean_error_db": -0.02194545454546315, "rmse_db": 0.0775690851770671, "max_absolute_error_db": 0.09634545454546384, "mean_absolute_error_db": 0.07440000000000069 }, "rounded_correction_offline": { "count": 2, "mean_error_db": -0.012000000000004007, "rmse_db": 0.07536152864691771, "max_absolute_error_db": 0.0864000000000047, "mean_absolute_error_db": 0.07440000000000069 } }, "all_included": { "original": { "count": 16, "mean_error_db": -22.89625625, "rmse_db": 22.902890416154357, "max_absolute_error_db": 24.0213, "mean_absolute_error_db": 22.89625625 }, "exact_fit_offline": { "count": 16, "mean_error_db": 0.09379829545454399, "rmse_db": 0.5591397579685385, "max_absolute_error_db": 1.0312454545454557, "mean_absolute_error_db": 0.44930170454545415 }, "rounded_correction_offline": { "count": 16, "mean_error_db": 0.10374375000000002, "rmse_db": 0.5608938530372756, "max_absolute_error_db": 1.0213000000000036, "mean_absolute_error_db": 0.4530312500000009 } }, "excluded_cases_descriptive_only": { "original": { "count": 2, "mean_error_db": -24.093200000000003, "rmse_db": 24.103872346160482, "max_absolute_error_db": 24.8104, "mean_absolute_error_db": 24.093200000000003 }, "exact_fit_offline": { "count": 2, "mean_error_db": -1.103145454545455, "rmse_db": 1.3157909157173475, "max_absolute_error_db": 1.8203454545454534, "mean_absolute_error_db": 1.103145454545455 }, "rounded_correction_offline": { "count": 2, "mean_error_db": -1.093200000000003, "rmse_db": 1.3074639880317944, "max_absolute_error_db": 1.8104000000000013, "mean_absolute_error_db": 1.093200000000003 } } }, "sensitivity": { "full_two_second_samples": { "sample_count_per_case": 2, "fitted_additive_db": 22.990545454545455, "fitted_shift_from_guarded_db": 0.0004909090909102076, "largest_active_case_reading_change_db": 0.0727, "fit_rounded_metrics": { "count": 11, "mean_error_db": 0.009454545454546028, "rmse_db": 0.5833177595756575, "max_absolute_error_db": 1.0075000000000003, "mean_absolute_error_db": 0.4980727272727272 } }, "observed_niosh_ranges": { "maximum_active_case_display_range_db": 0.3999999999999986, "fitted_additive_using_all_minima_db": 22.908236363636366, "fitted_additive_using_all_maxima_db": 23.06278181818182, "rounded_residual_bounds": { "fit": { "rmse_minimum_db": 0.5365676463326038, "rmse_maximum_db": 0.6674110822628545, "largest_possible_absolute_difference_db": 1.0909000000000049 }, "holdout": { "rmse_minimum_db": 0.5827174358125896, "rmse_maximum_db": 0.7146838065419809, "largest_possible_absolute_difference_db": 0.9855000000000018 }, "repeat": { "rmse_minimum_db": 0.04412346314603822, "rmse_maximum_db": 0.15735107244629665, "largest_possible_absolute_difference_db": 0.21359999999999957 } }, "interpretation": "Descriptive sensitivity to the observed display range. Not measurement uncertainty, error bars for absolute SPL, or a confidence interval." }, "including_lowest_250_hz_tone": { "fitted_additive_db": 23.022216666666665, "reason_not_primary": "This tone is too close to recorded background for the primary fit; reported here so the exclusion remains reviewable." } }, "repeat_check": { "niosh_last_minus_first_db": -0.10000000000000142, "lullasure_last_minus_first_db": 0.048799999999999955, "user_reported_setup_dba": 65, "user_reported_return_dba": [ 65.2, 65.4 ] }, "limitations": [ "Agreement to a reference app does not establish absolute acoustic accuracy or NIOSH endorsement.", "Post-correction values are calculated offline from the original recording, not measured in a rerun of the corrected app.", "Residuals vary by sound family; a single offset does not remove all frequency dependence.", "The retained cases span 47.8-70.8 dBA indicated by NIOSH; lower quiet-room levels, other phones, and other recording modes remain unverified.", "Same-session held-out sounds give a limited check; a fresh session and equipment-based work are still needed." ] }