Speed
See where playback speeds up or slows down within each rotation, alongside RPM and speed-stability results.
Groove Scope
DSR / Groove Scope
Hear the music.
For the love of vinyl. For the detail in your setup.
Hear the music.
Understand
your setup.
Meet Groove Scope: the iPhone measurement companion for audiophiles who want to get more from their turntable. Explore speed, channel balance, crosstalk and distortion—then reveal the recurring patterns behind the numbers with a Rotation Fingerprint.
Submitted for App Store review. Pro is a one-time lifetime unlock, with no subscription.
Four layers. One rotation.Speed, level, THD and crosstalk, viewed against relative platter angle.
A setup you can revisit.Save the evidence. Compare it after your next adjustment.
For vinyl enthusiasts, cartridge experimenters and meticulous system builders. Make your next setup decision with measured evidence alongside your listening.
MeasureA complete 1 kHz reference workflow
UnderstandFour rotation fingerprint layers
CompareSaved before-and-after evidence
The Groove Scope difference
A number tells you how much.
A fingerprint reveals the pattern.
Two measurements can have similar averages and different behaviour within each revolution. Groove Scope’s Rotation Fingerprint arranges consecutive rotations by relative angle, so you can inspect which features recur—and how they change between sessions.
Level
Inspect recurring output-level variation, with separate left and right reference views.
Distortion
Explore how total harmonic distortion varies around a revolution, beyond its overall percentage.
Crosstalk
Trace the leakage between channels across the rotation, alongside directional separation measurements.
From a quick check to a lasting referenceLive analysis, cartridge diagnostics, saved results, rotation patterns and before-and-after comparisons come together in one portable workflow. That is the value of Groove Scope: measurement depth you can return to as your system evolves.
Guided measurement
Play the reference tracks.
Let the detail emerge.
Connect your stereo USB audio interface and follow the guided left-only and right-only 1 kHz captures. Live level meters, tone analysis and playback RPM keep the measurement in view.
- Check the input before capture with RMS and peak meters.
- Follow clear prompts through the two reference tracks.
- Keep the measurement gain consistent across the pair.
Cartridge and speed diagnostics
Go deeper into the setup you care about.
Review channel balance, directional crosstalk, playback RPM, speed variation and distortion together. Inspect individual harmonics to understand how the two channels behave beyond the fundamental tone.
- RPM and speed error, with DIN-shaped wow & flutter RMS and raw speed-variation results.
- Left-to-right and right-to-left crosstalk, average separation and channel balance.
- THD per channel, H2–H5 harmonic profiles and measurement-quality context.
Before and after
Make a change.
See what changed.
Save a baseline, adjust one setup variable, and measure again under comparable conditions. Overlay the rotation profiles and inspect the measured differences in the context of normal variation between rotations.
- Explore speed, level, distortion and leakage patterns between sessions.
- See evidence thresholds and strength alongside the changes.
- “No clear difference” is a useful result when the evidence does not support a stronger conclusion.
A record of your playback system
Your reference stays with you.
Name your measurements so a cartridge adjustment, interface check or repeat session remains easy to find. Revisit the complete result, open its fingerprint, and share a PDF report when you want another pair of eyes.
- Keep dated results and the recorded input identity together.
- Return to the numbers and patterns after the listening session.
- Build a practical history of your setup as it evolves.
Actual Groove Scope screens. Tap any screenshot to view it full size. Example readings describe the captured setup and conditions.
An openly documented technical foundation
The method behind the fingerprint is open to inspection.
DSR’s Vinyl Playback Fingerprint method defines a persistent measurement record that brings objective results together with their validity, repeatability information and acquisition context. The published technical note identifies Groove Scope as its first reference implementation.
DSR Technical Journal · Technical note · Version 1.0
Vinyl Playback Fingerprint: A Persistent Multidimensional Method for the Objective Characterisation and Comparison of Analogue Record Playback
Michelangelo Canonico · Direct Sound Records · 3 September 2026
The published core profile combines speed accuracy, weighted wow and flutter, channel balance, stereo separation, directional crosstalk asymmetry and THD. The app’s Rotation Fingerprint adds a way to inspect recurring speed, level, leakage and THD patterns across consecutive revolutions.
The note establishes the method architecture; empirical repeatability and inter-device reproducibility validation remain ongoing. These measurements characterise the captured playback chain. They do not, on their own, establish a mechanical cause or an audible improvement.
A practical audiophile workflow
Bring your turntable.
Keep the lab in your pocket.
Use a test record with dedicated left-only and right-only 1 kHz reference tracks, a suitable phono stage and a compatible stereo USB audio interface connected to your iPhone.
The app analyses the electrical playback signal. Keep the test record, input gain and capture conditions consistent when comparing setup changes.
01
Connect the playback chain
Route the phono-stage line output into both interface inputs, or use an interface with a suitable phono input. The interface must expose two simultaneous input channels to iOS.
02
Capture a baseline
Follow the left and right reference-track prompts. Check levels and save a clearly named result before adjusting your setup.
03
Change, repeat, compare
Change one variable, repeat the capture and inspect both the summary measurements and rotation patterns. Repeat variable diagnostics before making further adjustments.
Free and Pro
Start with a check.
Unlock the complete picture.
Free access provides signal readiness and a 1 kHz azimuth quick check. Pro brings the deeper diagnostics, saved history, fingerprint comparisons and reporting together in a single lifetime purchase.
| Capability | Free | Pro |
|---|---|---|
| Signal readiness and 1 kHz azimuth quick check | Included | Included |
| Full azimuth, balance and crosstalk diagnostics | — | Included |
| RPM, speed stability, THD and harmonic analysis | — | Included |
| Saved measurements and history | — | Included |
| Rotation Fingerprint and before-and-after comparison | — | Included |
| Shareable PDF reports | — | Included |
One payment. No subscription. App Store availability pending review; pricing will be shown in the app.
Before you start
A few useful answers.
Does it measure through the iPhone microphone?
The featured stereo reference workflow uses the electrical signal from your playback chain through a compatible USB audio interface. It needs both input channels to assess directional crosstalk and channel behaviour.
Do I need a particular test record?
Use a record with dedicated left-only and right-only 1 kHz reference tracks. Check that the track arrangement matches the guided workflow. The test record and its condition are part of the measurement chain.
What does the fingerprint tell me?
It lets you inspect recurring variation across consecutive rotations in four layers: speed, level, leakage and THD. Compare saved profiles to see where patterns agree or differ. It is a signature of the captured playback conditions, not a universal sound-quality score.
Can it prove that a cartridge adjustment sounds better?
It can document a measured change and help you judge whether that change exceeds observed variation. Audibility, preference and the cause of a change need additional evidence. Use measurements to inform your listening and repeat uncertain results.
Is the wow and flutter value a certified standards measurement?
The app labels its result as DIN-shaped wow & flutter RMS and also shows raw speed-variation measures. Compare like-for-like methods, test tones and conditions; the app does not claim instrument certification.
Is Groove Scope available now?
Groove Scope has been submitted for App Store review. The planned offering includes a free quick-check workflow and a one-time lifetime Pro unlock. A download link will be added when the app is available.
Groove Scope by Direct Sound Records
Give your next adjustment
a reference point.
From the first channel check to a four-layer rotation fingerprint, discover more about the playback system you have put so much into.
Results depend on the test record, playback chain, interface and capture conditions. Repeat measurements under comparable conditions before drawing conclusions about a setup change.