Comparison

Crystal Synth XT vs Singing Tutor

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

Head to head
About

Crystal Synth XT

Create lush, evolving soundscapes with a powerful semi-modular synthesizer for mobile devices. Explore subtractive and FM synthesis, extensive modulation, and built-in effects. Share sounds with the desktop version and connect MIDI keyboards for a full hardware synth experience.

Highlights
  • Semi-modular synthesis engine
  • Subtractive and FM synthesis
  • Extensive modulation control (>90 parameters)
  • Multi-stage envelopes with graphical editors
  • Tempo-synced envelopes, LFOs, and delays
  • Built-in effects (chorus, flanger, echo)
  • MIDI keyboard input and virtual MIDI support
Features
Read full description

Crystal Synth XT is a full featured semi-modular synthesizer, ideally suited to creating lush evolving soundscapes. Crystal VST has long been a popular synthesizer on the desktop. Crystal Synth XT brings that same powerful synthesis engine to the iPad and iPhone. Crystal Synth XT features MIDI keyboard input via Apple's camera adapter and sharing of sounds with the desktop version of Crystal. == Features == Browse through the included sounds and use the 2 octave keypad or keyboard to trigger notes to produce evolving, rhythmic, or melodic sounds. Create your own sounds with a single button press using the breed feature. When using an iPad, you can delve into a tweaker's dream by using the extensive editing features to sculpt sounds to your heart's content (editing features are only available when used on an iPad). Crystal features both subtractive synthesis and frequency modulation (FM) synthesis. It offers abundant modulation control with over 90 parameters which may be modulated, multi-stage envelopes with graphical editors, extensive tempo sync of envelopes/lfo rates/delay times, built-in effects for chorus/flanging/comb filtering/echoes, and a band splitter for effects processing by frequency band. Not only that, Crystal has wave sequencing and granular synthesis. The musical applications for Crystal are literally boundless. == MIDI == With MIDI keyboard input, you can connect a MIDI keyboard to your iPad or iPhone and play Crystal Synth XT like a hardware synth. == Virtual MIDI == Use virtual midi to play Crystal Synth XT from a midi controller app. Use the Settings app to turn on the Background Audio mode to enable Crystal to play audio when in the background. You can then play Crystal from a midi controller app which supports virtual midi. == Sharing == With patch sharing you can create sounds on your iPad or iPhone while away from the studio, then transfer them to the desktop Crystal when you get back to the studio to use in recording projects. Or, create banks of sounds on the desktop Crystal, then transfer them to the iPad/iPhone Crystal to use in a live performance for a truly portable rig. Use Audio copy/paste to record your performance on Crystal and transfer that performance to another app. Or copy your recorded performance to your computer. == Inter App Audio and Audiobus == To use IAA or Audiobus to record into other apps, turn on Background Audio for Crystal Synth XT in the Settings app. See demonstration videos on the greenoak.com website. == Different Versions == If you don't need all the features of Crystal Synth XT, try the basic version of Crystal, also available in the app store from Green Oak Software. With the basic version you can browse sounds, play notes, and create new sounds, taking advantage of its powerful semimodular synthesis engine. The XT version adds features like MIDI keyboard input via the iPad's camera adapter, IAA/Audiobus, and patch sharing with the desktop version. Choose the app that is best for you! == Notes == Important note for iPhone users: Crystal Synth XT runs on both the iPad and the iPhone. Because of the limited screen space on the iPhone however, the editing pages, which contain the edit controls, are not available when running on that device. However, on the iPhone you can still browse sounds, play notes from the keypad, create new sounds with the Breed feature, modify patches with the Design feature, and share sounds with desktop Crystal VST. For videos and information about Crystal Synth XT, visit: http://www.greenoak.com

About

Singing Tutor

Enhance your singing and musical abilities with real-time voice analysis and visual feedback. Practice with customizable tracks and record your performances for later review.

Highlights
  • Real-time voice analysis
  • Visual reference tracks
  • Customizable practice sessions
  • Volume indicator
  • Background track playback
  • Recording and playback
  • Audio export
Features
Read full description

Singing Tutor is a real-time pitch training tool that shows you exactly where your voice lands as you sing - note by note, with instant visual feedback on a scrolling piano-roll display. Whether you're a vocal coach running lessons, a student working through exercises, or someone who loves karaoke night, Singing Tutor turns your device into a precise vocal practice studio. REAL-TIME PITCH FEEDBACK - Sing along to MIDI or karaoke (.kar) while watching your pitch accuracy in real time. The app draws your voice as a continuous line over the reference melody, so you can see exactly where you're sharp, flat, or right on target. No guesswork - just clear, visual feedback that helps you improve faster than listening alone. FULL KARAOKE LYRICS DISPLAY- Load any .kar karaoke file and see synchronized lyrics scroll across the screen as the music plays. Customize every aspect of the lyrics display: font size, highlight and base colors, animation timing, line opacity, number of visible lines, text alignment, and more. Supports a wide range of text encodings - including Japanese (Shift-JIS, EUC-JP), Chinese (GBK, Big5), Korean (EUC-KR), Cyrillic, and many others - so your international karaoke library works out of the box. The active syllable highlights in real time, giving you a true karaoke experience with pitch training on top. AUDIO DEVICE & MIXER CONTROLS - Choose exactly which audio output device and input microphone to use. The built-in mixer gives you independent volume control over four output tracks - Background, Melody, Accompaniment, and Voice Reference . So you can dial in the perfect practice mix. Mute or solo any track instantly. On the input side, configure your microphone and enable or disable mic loopback to hear yourself through your speakers while you sing. VISUAL REFERENCE TRACKS - Load a MIDI or karaoke file and see the target melody displayed as note blocks on the piano-roll. You can also load previously recorded voice files (.stf) as a visual reference - great for comparing today's attempt against your personal best. Follow the melody visually while you sing, and watch your voice line track against the target notes. BACKING TRACK PLAYBACK - Load any MP3 as a backing track to sing along with during practice. MP3 tracks play as audio only — no visual reference on the piano-roll — making them ideal when you know the melody and just need accompaniment. Use the built-in mixer to set the backing track volume exactly where you want it. CUSTOMIZABLE PRACTICE SESSIONS - Toggle individual tracks on or off during playback or recording. Turn off the melody line to test yourself, keep the accompaniment for context, or solo the voice reference to study phrasing. Every combination is available for both Play and Record modes, so you can structure sessions around exactly what you're working on. RECORDING, PLAYBACK & EXPORT - Record your singing sessions and save them as .stf voice files for later review. Replay any recording with the reference track to see how your pitch compared. When you're ready to share, export your recording - including the background track - as an MP3 file. LATENCY COMPENSATION - On some systems, audio input and output can be slightly out of sync. The Latency Compensate setting lets you adjust the voice line and cursor offset in milliseconds, so what you see on screen accurately reflects when you actually sang each note. Dial it in once and every session stays aligned. VOLUME INDICATOR - A real-time volume meter sits next to the piano keyboard, showing your current input level at a glance. In Duet mode, two independent meters are displayed - one per singer. Singing Tutor works with the files you already have. Load MIDI files for melody and accompaniment, .kar files for karaoke with lyrics, or MP3s for backing tracks. No built-in song library required - use any song you want. Start singing. See exactly how you sound.

Screenshots

Crystal Synth XT1 screens
Singing Tutor4 screens

Verdict

The call

The clearest difference is review sentiment: Crystal Synth XT at 78% against Singing Tutor's 18%. Singing Tutor's advantage is price ($0.99 vs $4.99). On update cadence, ads, in-app purchases and monetization model 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

Crystal Synth XT costs $4.99 and Singing Tutor $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Crystal Synth XT ships an update every 4 months, Singing Tutor every 5 months. Both last shipped on November 1, 2026.

Scorecard2 real differences · 8 level
Crystal Synth XT versus Singing Tutor: the parameters behind the verdict, then further details
ParameterCrystal Synth XTSinging Tutor
Price$4.99$0.99 — better
Rating4.9 (22 ratings) — better—
Positive reviews78.4% of reviews — better18.2% of reviews
Number of ratings22 — better—
Update frequencyEvery 4 months — betterEvery 5 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod, Mac — better
Requires iOS11.0 — better12.0
Further details — not scored
Size36 MB48 MB
Age rating4+4+
DeveloperGreen Oak SoftwareAnton Plakhotnyk

Customer experience

Crystal Synth XT

All ratings20 ratings
Positive95.0%
Neutral5.0%
Negative0.0%
Written reviews74 reviews
Positive78.4%
Neutral8.1%
Negative13.5%

Singing Tutor

Written reviews11 reviews
Positive18.2%
Neutral9.1%
Negative72.7%

Bugs and requests

Crystal Synth XT

Reported bugs

15 issues
  • App not working, splash screen disappears
  • Screen in background
  • Envelope points not moving
  • Breed fan not working properly
  • Crashing on launch
Show 10 more
  • Clicks and crashes when adjusting parameters
  • Sounds distorted and buggy
  • Won't play any sounds
  • Crashes when hitting record
  • Play surface stopped responding
  • Crash when trying record function
  • Crackles and pops in sound engine
  • Audiobus fails, breaks up when switching apps
  • Preset name editing gone after iOS 7 update
  • Splash screen appears for a second, then disappears

Requested features

22 requests
  • AUv3 support
  • Update to an AU3 standard
  • Newer interface
  • Fix breed fan access to all presets
  • Fix preset system variations between devices
Show 17 more
  • AUv3 implementation
  • Update the envelope points
  • AUv3 standard transformation
  • Multiple instances in DAWs
  • Dark mode option
  • Advanced analytics dashboard
  • Fix preset name editing
  • In-app purchase for a second instance
  • Load/Save banks
  • Metronome or timer capability
  • Newer app icon
  • Redesign for Retina Display
  • Polyphony on iOS version
  • Recording facility
  • Keyboard option
  • Virtual MIDI support
  • Advanced patch editing on iPod version

Singing Tutor

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Crystal Synth XT

No in-app purchases

None

Singing Tutor

No in-app purchases

Questions

Is Crystal Synth XT free?
Crystal Synth XT costs $4.99, with no in-app purchases.
Is Singing Tutor free?
Singing Tutor costs $0.99, with no in-app purchases.
Do Crystal Synth XT or Singing Tutor have ads?
Neither Crystal Synth XT nor Singing Tutor shows ads.
Which is updated more often, Crystal Synth XT or Singing Tutor?
Crystal Synth XT ships an update every 4 months, and Singing Tutor every 5 months. Most recently, Crystal Synth XT was updated on November 1, 2026 and Singing Tutor on November 1, 2026.

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