{ "$schema": "../../data/schema/measurement.schema.json", "schema_version": "1.0.0", "language": "en", "creator": { "name": "Michelangelo Canonico", "role": "Creator and lead measurer", "affiliation": "Direct Sound Records" }, "publisher": { "name": "Direct Sound Records", "url": "https://directsoundrecords.com/", "location_label": "London–Rome" }, "software": { "name": "Groove Scope", "report_generator_label": "Groove Scope Reference", "application_version": "not_recorded", "analysis_method_version": "not_recorded", "platform": "not_recorded", "developer": "Michelangelo Canonico / Direct Sound Records" }, "related_applications": [ { "name": "Resonance Lab", "relationship": "Companion application for tonearm and cartridge resonance planning", "url": "https://directsoundrecords.com/resonance-lab/" } ], "measurement_type": "1 kHz Reference Check", "measurement_scope": [ "playback speed", "rotational stability", "DIN-shaped wow and flutter", "channel balance", "electrical crosstalk", "distortion diagnostics", "harmonic profile", "rotation fingerprints" ], "license": "CC-BY-4.0", "measurement_id": "GS-2026-0008", "record_version": "0.9.0", "publication_status": "draft", "title": "Ortofon 2M Bronze — Rega P3 / Audio Research SP20 / EVO4 — 1 kHz Reference Check", "source_report_title": "Ortofon 2M Bronze - Rega P3 - Audio Research SP20 - EVO4", "slug": "gs-2026-0008-ortofon-2m-bronze-rega-p3-1-khz-reference-check", "measurement_datetime_local": "2026-10-02T09:44:00", "measurement_timezone": "not_recorded", "date_published": "2026-10-02", "sample_id": "not_recorded", "setup": { "turntable": "Rega P3", "tonearm": "not_recorded", "cartridge": "Ortofon 2M Bronze", "stylus": "not_recorded", "cartridge_hours": "not_recorded", "vertical_tracking_force_g": "not_recorded", "anti_skate_setting": "not_recorded", "alignment_geometry": "not_recorded", "azimuth_setting": "not_recorded", "vta_or_sra_setting": "not_recorded", "phono_stage": "Audio Research SP20", "phono_gain_db": "not_recorded", "cartridge_loading": "not_recorded", "test_record": "not_recorded", "test_record_track": "not_recorded", "test_record_condition": "not_recorded", "nominal_test_tone_hz": 1000, "audio_interface_reported_label": "EVO4", "audio_interface_full_model": "EVO4", "interface_gain_settings": "not_recorded", "sample_rate_hz": "not_recorded", "bit_depth": "not_recorded", "capture_device": "not_recorded", "channel_routing": "not_recorded", "measurement_location": "not_recorded" }, "results": { "playback_rpm": { "value": 33.34, "classification": "primary", "condition": "under_stylus_load" }, "playback_speed_error_percent": { "value": 0.01, "classification": "primary", "direction": "fast" }, "settled_rpm": { "minimum": 33.26, "maximum": 33.41, "span": 0.15, "classification": "primary" }, "din_shaped_wow_flutter_percent": { "value": 0.027, "classification": "primary" }, "raw_speed_variation_percent": { "rms_plus_minus": 0.125, "two_sigma_plus_minus": 0.249, "classification": "unweighted_diagnostic" }, "raw_wow_flutter_percent": { "wow_rms": 0.12, "flutter_rms": 0.032, "classification": "unweighted_diagnostic" }, "channel_balance_db": { "value": 0.53, "classification": "diagnostic_only" }, "crosstalk_1khz_db": { "average_separation": 32.8, "left_to_right": -33.2, "right_to_left": -32.4, "directional_difference": 0.78, "classification": "supporting" }, "thd_percent": { "left": 0.98, "right": 1.13, "left_minus_right_percentage_points": -0.15, "classification": "diagnostic" }, "harmonic_profile_db": { "h2": { "left": -40.3, "right": -39.1 }, "h3": { "left": -59.5, "right": -57.1 }, "h4": { "left": -63.2, "right": -58.9 }, "h5": { "left": -74.5, "right": -66.6 }, "classification": "diagnostic" }, "harmonic_difference_summary_db": { "h2_right_higher": 1.2, "h3_right_higher": 2.4, "classification": "source_report_summary" }, "harmonic_reliability": { "classification": "repeat_before_setup_change", "quality_note": "The right channel's third harmonic changed most during recording. Repeat before changing the cartridge setup." } }, "interpretation": { "summary": "The Ortofon 2M Bronze delivers strong 1 kHz separation in this Rega P3 / Audio Research SP20 / EVO4 capture: 32.8 dB on average, with +0.53 dB channel balance. Playback averaged 33.34 RPM (+0.01%) with 0.027% DIN-shaped wow and flutter. THD was 0.98% left and 1.13% right; repeat the right-channel third-harmonic check before changing setup.", "recommendation": "Retain this promising channel-performance baseline and repeat the capture before changing cartridge setup, as the report advises. Document loading, tracking force, test-record and capture settings for reproducible comparisons.", "repeat_required": true }, "provenance": { "source_type": "Groove Scope generated PDF report", "source_file": "report.pdf", "data_entry_method": "Values transcribed verbatim from the original PDF report; rounded differences are preserved rather than recalculated.", "raw_audio_published": false, "raw_audio_note": "No raw test-record audio is included.", "sample_ownership": "not_recorded", "setup_metadata_source": "The source report title identifies Ortofon 2M Bronze, Rega P3, Audio Research SP20 and EVO4. The input field reports EVO4.", "known_limitations": [ "Tonearm, stylus, loading, tracking force, alignment, anti-skate, test-record identity and track, capture settings, software versions, timezone and repeat count were not supplied.", "The right-channel third harmonic varied during this recording; repeat before changing cartridge setup, as the source report states.", "Reported differences retain source precision and may differ from subtraction of rounded channel values.", "Manufacturer figures provide context; this complete playback-chain capture is not a controlled certification of the cartridge alone." ], "fingerprint_channel_assignment": "L/R labels follow the order of the two screenshots supplied for each metric; the screenshots themselves do not display channel labels.", "photo_treatment": "Supplied photograph cosmetically retouched with AI for background, lighting, colour and dust removal. Original HEIC preserved. Fingerprint PNGs are unedited and web copies use lossless WebP." }, "files": { "human_readable_record": "README.md", "source_report": "report.pdf", "checksums": "checksums.sha256", "source_hero": "assets/source/hero-original.heic", "rotation_fingerprints": [ "assets/source/speed-deviation-left.png", "assets/source/speed-deviation-right.png", "assets/source/level-modulation-left.png", "assets/source/level-modulation-right.png", "assets/source/opposite-channel-leakage-left.png", "assets/source/opposite-channel-leakage-right.png", "assets/source/harmonic-distortion-left.png", "assets/source/harmonic-distortion-right.png" ], "retouched_hero": "assets/hero-retouched.png", "image_edit_prompt": "assets/image-edit-prompt.txt" }, "keywords": [ "Groove Scope", "Direct Sound Records", "Michelangelo Canonico", "Ortofon 2M Bronze", "Rega P3", "Audio Research SP20", "EVO4", "vinyl measurement", "rotation fingerprint", "wow and flutter", "cartridge crosstalk" ], "external_references": [ { "title": "Ortofon 2M Bronze manufacturer specifications", "url": "https://ortofon.com/products/2m-bronze", "accessed": "2026-10-02", "channel_separation_1khz_db": 26, "channel_balance_1khz_db": 1 } ] }