# Direct Sound Records Measurements

> Human-readable and machine-readable acoustic, audio-signal and mechanical measurement archives published by Direct Sound Records.

The measurement hub brings together three public datasets:

1. SPL Reference Measurements — reviewed public environmental sound-level observations contributed through DSR SPL Reference.
2. Groove Scope Measurements — audio and test-record observations of vinyl playback systems.
3. Resonance Lab Measurements — setup-centric mechanical observations including RPM, unweighted wow and flutter, 1–40 Hz vibration and cartridge/tonearm resonance context.

Measurements describe documented physical setups and sessions, not universal manufacturer specifications. Preserve public IDs, UUIDs, provenance, software/method versions, measurement conditions, limitations and publication status when citing or analysing a record.

## Hub

- [Direct Sound Records Measurements](https://measurements.directsoundrecords.com/): Human-readable entry point for all DSR measurement archives.
- [Direct Sound Records](https://directsoundrecords.com/): Official publisher website.

## SPL Reference Measurements

- [SPL Reference collection](https://measurements.directsoundrecords.com/spl-reference/): DSR overview and privacy boundary.
- [Interactive public library](https://directsoundrecords.github.io/spl-reference-measurements/): Searchable public measurement catalogue.
- [SPL Reference GitHub repository](https://github.com/directsoundrecords/spl-reference-measurements): Canonical structured records and public photographs.

## Groove Scope Measurements

- [Groove Scope archive](https://measurements.directsoundrecords.com/groove-scope/): Human-readable Groove Scope measurement index.
- [Groove Scope GitHub repository](https://github.com/directsoundrecords/groove-scope-measurements): Versioned technical archive, schema, reports and structured data.
- [GS-2026-0003](https://measurements.directsoundrecords.com/groove-scope/measurements/GS-2026-0003.html): Rega P3 / Rega RB330 / Audio-Technica AT-OC9XML / Audio Research SP20 1 kHz reference check recorded on 5 September 2026; the measured 31.8 dB average separation and 0.24 dB channel-balance magnitude compare strongly with Audio-Technica's published 27 dB and 1.0 dB figures.
- [Groove Scope catalogue manifest](https://measurements.directsoundrecords.com/groove-scope/catalog.json): Static discovery data for the current measurement pages, status, hero assets and primary metrics.
- [Groove Scope project page](https://directsoundrecords.com/groove-scope-measurements/): Editorial explanation and methodology context.

## Resonance Lab Measurements

The current public Resonance Lab archive contains 2 Setups and 9 independent observations.

- [Resonance Lab archive](https://measurements.directsoundrecords.com/resonance-lab/): Human-readable setup-centric Resonance Lab index.
- [Resonance Lab GitHub repository](https://github.com/directsoundrecords/resonance-lab-measurements): Canonical structured Setup and Measurement archive.
- [DSR-SETUP-0001](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0001/): Rega P3 / Rega RB330 / Audio-Technica AT-OC9XML with three public observations.
- [RL-2026-000001](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0001/measurements/RL-2026-000001/): RPM observation, average 33.396 RPM, unweighted wow & flutter 0.0346%.
- [RL-2026-000002](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0001/measurements/RL-2026-000002/): RPM observation, average 33.404 RPM, unweighted wow & flutter 0.0396%.
- [RL-2026-000003](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0001/measurements/RL-2026-000003/): 1–40 Hz vibration observation, capture RMS 1.362 mg.
- [DSR-SETUP-0002](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/): Technics SL-1410 mk2 / AMG 12J2 / Ortofon 2M Blue with six public observations.
- [RL-2026-000004](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000004/): RPM observation, average 33.349 RPM, unweighted wow & flutter 0.0243%.
- [RL-2026-000005](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000005/): RPM observation with record present and stylus tracking, average 33.344 RPM, unweighted wow & flutter 0.0266%.
- [RL-2026-000006](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000006/): 1–40 Hz vibration observation, capture RMS 1.094 mg; operating context not recorded.
- [RL-2026-000007](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000007/): 1–40 Hz vibration observation, capture RMS 1.087 mg; phone on top plate, motor off, speakers inactive.
- [RL-2026-000008](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000008/): 1–40 Hz vibration observation, capture RMS 2.094 mg; phone on turntable plinth, motor off, speakers active.
- [RL-2026-000009](https://measurements.directsoundrecords.com/resonance-lab/setups/DSR-SETUP-0002/measurements/RL-2026-000009/): 1–40 Hz vibration observation, capture RMS 1.266 mg; phone on platter, motor off, speakers active.
- [Resonance Lab project page](https://directsoundrecords.com/resonance-lab-measurements/): Editorial explanation of the public archive.

## Scientific interpretation

Groove Scope results belong to the documented playback chain and capture session.

Resonance Lab predicted cartridge/tonearm resonance and phone-measured vibration are different evidence types. Phone vibration describes mechanical motion at the phone placement point and is not a direct measurement of stylus/cantilever or cartridge/tonearm resonance. Dominant local spectral peaks are also distinct from stronger significant/confident-peak classifications.