Comparison

User Scale vs AU Studio

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

User Scale

This iPad application allows musicians to control the tuning scale of their Roland instruments. It enables real-time adjustments to key tunings, applying consistent values across notes of the same name during performances.

Highlights
  • Control tuning scale with iPad
  • Change instrument key tunings
  • Apply consistent tuning values
  • Real-time performance control
Read full description

This software application for iPad lets you change the tuning scale of your Roland musical instrument. When using User Scale you can: • Play your Roland musical instrument while controlling the tuning scale of your performance with your iPad • Change the tuning of your musical instrument’s keys. Apply the same values to all notes of the same name App requires: - Apple iPad Camera Connection Kit (camera connectors made by Apple Inc.) and USB cable (type A–male to type B–male, commercially available) -or- - Roland musical instrument that supports the wireless LAN function

About

AU Studio

This app acts as a dedicated host for Audio Unit extensions, allowing musicians and developers to inspect, audition, and test installed audio plugins. It provides detailed information about each unit's capabilities and behavior without requiring a full digital audio workstation.

Highlights
  • Scan and catalog installed Audio Units
  • Filter plugins by developer, type, and status
  • Load AUv3 interfaces or use detailed inspector
  • Inspect registry identity, MIDI support, and parameters
  • Route CoreMIDI sources and audition audio effects
  • Monitor runtime CPU and memory usage
  • Built-in manual for guidance
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AU Studio is a focused Audio Unit host, not a DAW. Open the plug-ins you already own, hear them in seconds, and see exactly what they expose. Made for musicians, sound designers, and Audio Unit developers who need a fast, honest test bench. No session to build, no tracks to arm. Pick a unit from your catalog and its interface opens in a panel of its own, named and sized to the plug-in, with your host controls in a bar above it. Key features: - Scan the instruments, effects, music effects, generators, and MIDI processors already installed on your device: AUv3 on iPhone, iPad, and Apple Vision Pro, plus AUv2 on Mac. - Filter by developer, type, or search text, and hide Apple built-ins to focus on third-party gear. - Open a plug-in's own interface when it ships one, and fall back to a metadata view when it doesn't, with the full inspector always one tap away. - Inspect identity, four-character codes, version, sandbox and cached validation status, MIDI support, busses, parameters, presets, latency, and tail time. - Step through factory presets, then save your own working state without leaving the interface. - Play instruments from the floating MIDI keyboard: notes, pitch bend, mod wheel, auto, mono or poly voicing, a shiftable range, and one-tap panic for stuck notes. Your hardware controller lights up the on-screen keys as you play. - Run a guitar, a microphone, or any channel of your interface through a loaded effect. Pick the device, pick mono or stereo, pick the channels. - Load a track into the floating media player, scrub the waveform, loop a section, and play along with your live input at the same time. - Check a signal path in seconds with the built-in test tone. - Route external CoreMIDI sources in, and send generated MIDI back out to a CoreMIDI destination. - Test MIDI 2 units with automatic, MIDI 1, or MIDI 2 protocol selection: high-resolution notes, registered and per-note controllers, per-note pitch bend, discovered MIDI-CI Profiles, and a monitor showing raw or decoded MIDI going in and coming out. - Choose your output device on Mac, and set sample rate, buffer size, and which MIDI sources are enabled. - Keep host-process CPU and memory in view while you work. - Open unfamiliar plug-ins with less risk. AU Studio asks first when the system does not mark a unit sandbox-safe, and a peak limiter sits across the host output. - Read the built-in manual, fully searchable: discovery, routing, presets, hardware input, floating tools, troubleshooting, and developer notes. What AU Studio is: A focused host for discovering, opening, auditioning, and inspecting the Audio Units already on your device. It answers the practical questions: Is the unit visible? Does it load? Does it have an interface? What busses, parameters, presets, and MIDI capabilities does it expose? Does MIDI reach it? Does audio pass through it? What AU Studio is not: It is not a DAW. No multitrack recording, clip launching, timeline arrangement, piano-roll sequencing, MIDI learn, automation lanes, song export, or mastering tools. AU Studio ships no Audio Unit of its own — no instrument, no effect, no DSP engine. It hosts the units other apps provide and wraps them in host-owned routing, auditioning, and inspection. Discovery uses the system Audio Unit registry. If a provider app is not installed, not enabled, or not visible to the platform, AU Studio cannot invent it. Interface behavior, presets, parameter meaning, MIDI mapping, and DSP results belong to each Audio Unit.

Screenshots

AU Studio4 screens

Verdict

The call

The clearest difference is review sentiment: User Scale at 100% against AU Studio's 50%. User Scale also leads on price (Free vs $9.99) and iOS requirement (8.1 vs 17.0). AU Studio's advantage is rating (4.5 vs 3.5) and update cadence (monthly vs every 13 months). On ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

User Scale is free to download; AU Studio costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

AU Studio holds the better App Store score, 4.5 against 3.5. Both are backed by a comparable volume of ratings — 2 and 4 respectively. Written reviews complicate that: 100% of User Scale's written reviews are positive against 50% of AU Studio's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

User Scale ships an update every 13 months, AU Studio monthly. The most recent releases landed on September 30, 2026 and October 1, 2026 respectively.

Scorecard7 real differences · 3 level
User Scale versus AU Studio: the parameters behind the verdict, then further details
ParameterUser ScaleAU Studio
PriceFree — better$9.99
Rating3.5 (2 ratings)4.5 (4 ratings) — better
Positive reviews100.0% of reviews — better50.0% of reviews
Number of ratings24 — better
Update frequencyEvery 13 monthsMonthly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPadiPhone, iPad, Mac, Vision Pro — better
Requires iOS8.1 — better17.0
Further details — not scored
Size8 MB7 MB
Age rating4+4+
DeveloperRoland CorporationChristian Thompson

Customer experience

User Scale

All ratings2 ratings
Positive50.0%
Neutral0.0%
Negative50.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

AU Studio

All ratings4 ratings
Positive75.0%
Neutral25.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral50.0%
Negative0.0%

In-app purchases

None

User Scale

No in-app purchases

None

AU Studio

No in-app purchases

Questions

Is User Scale free?
User Scale is free to download, with no in-app purchases.
Is AU Studio free?
AU Studio costs $9.99, with no in-app purchases.
Which has better reviews, User Scale or AU Studio?
AU Studio is rated higher. User Scale averages 3.5 out of 5 from 2 ratings, while AU Studio averages 4.5 from 4 ratings.
Do User Scale or AU Studio have ads?
Neither User Scale nor AU Studio shows ads.
Which is updated more often, User Scale or AU Studio?
User Scale ships an update every 13 months, and AU Studio monthly. Most recently, User Scale was updated on September 30, 2026 and AU Studio on October 1, 2026.

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