Comparison

AudioKit Digital D1 Synth vs Spectrum Synthesizer Bundle

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

Head to head
About

AudioKit Digital D1 Synth

This app is a virtual analog and PCM synthesizer for iPad, inspired by the digital synthesizers of the 80s and 90s. It offers a vast library of presets, advanced synthesis features, and built-in effects for creating rich, retro-inspired sounds.

Highlights
  • 64-voice hybrid digital poly synthesis
  • 1GB+ of original samples
  • Stand-alone, IAA, and AUv3 support
  • Vintage-style arp/step sequencer
  • 3 LFOs with fun routings
  • Dual independent per-layer filters
  • Built-in FX suite
Read full description

Epic 64-voice Virtual Analog / PCM iPad Synth Inspired by the Digital Synths of the 80s and 90s - ** TOP 3 iOS MUSIC APPS OF 2018 *** - Music Radar Awards (Computer Music & Future Music Magazine) - * Featured By Apple in "New Apps We Love!" ** "Fans of the D-50, JD-990, 01/W, Wavestation... Rejoice!" - Music Radar FULLY LOADED w/ 500+ presets by Brice Beasley, Matthew Fecher, Red Sky Lullaby, Jakob Haq, Dean Daughters (Electronisounds), Sound of Izrael, Brian Funk, and more DIGITAL D1 is AWESOME: - 64-voice Hybrid Digital Poly Synthesis. - Full 1+ Gigabyte of original samples recorded from analog & fm synths over 30+ years old - Stand-alone iPad Synth, plus IAA & Audiobus - Basic AUv3 Plugin support. Works best with AUM. We're working on upgrading Audio Unit support. - Space-saving Compression - The whole app is under 200mb! - Dual layers per voice. Keyboard splits. Velocity Scaling. - Vintage-style Arp/Step Sequencer that can be routed to specific layers. - 3 LFOs. Fun Routings. LFOs can modify other LFOs. - Dual Independent per-Layer filters - Plus, per-voice Harmonic key-tracked Envelope filters. "Digital D1 Sounds and plays AMAZING!" - The Sound Test Room "Rad retro synth sounds" - Cult of Mac, App of the Week "AudioKit Digital D1 is a beautiful Synthesizer app that recreates the spirit of legendary synths" - Synth Anatomy ADDITIONAL FEATURES: - FX: Glorious Reverb, Phaser, Digital Delay, Distortion, Flanger, Chorus, Crush, and more. - Perfect with a MIDI Keyboard - Ableton Link - All kinds of awesome stuff - The Sound. Oh, the sound. You won't believe it. "Digital D1 synth is pure ‘80s and ‘90s digital lushness" - Computer Music/Music Radar "Beautiful. Lush. Modern and Amazing… An Instant Classic." REQUIREMENTS: Requires newer iPads for best performance. May be slow on iPad 4. IAA is being deprecated by Apple in iOS 13. We're moving to AUv3 as well. Please replace IAA with AUv3 in your projects. GarageBand Audio Unit (AUv3): You can run one instance of D1 as an AUv3 in GarageBand. With a host like AUM, you can run 3 or more instances at once. TROUBLESHOOTING: For iPad 4 - Open the "Settings" button (to the upper left above the keyboard). Turn the buffer to 512 or above. And turn the "CPU Efficient" toggle to on. If still having trouble, try closing other music apps and/or rebooting your iPad. Thanks! - * NOMINATED: Best iOS Music Apps of 2018 ** by Computer Music & Future Music magazine. Subscribe to access to premium app features; subscription details are the following: - Length: weekly or yearly - Free trial: only on selected subscriptions - Your payment will be charged to your iTunes Account as soon as you confirm your purchase - You can manage your subscriptions and turn off auto-renewal from your Account Settings after the purchase - Your subscription will renew automatically, unless you turn off auto-renew at least 24 hours before the end of the current period - The cost of renewal will be charged to your account in the 24 hours prior to the end of the current period - When canceling a subscription, your subscription will stay active until the end of the period. Auto-renewal will be disabled, but the current subscription will not be refunded - Any unused portion of a free trial period, if offered, will be forfeited when purchasing a subscription Terms & Conditions: [https://magic-cake-e95.notion.site/AudioKit-Digital-D1-Synth-Terms-Conditions-14dcf6557a0880beb991f20561329664?pvs=4](https://www.notion.so/AudioKit-Digital-D1-Synth-Terms-Conditions-14dcf6557a0880beb991f20561329664?pvs=21) Privacy Policy: [https://magic-cake-e95.notion.site/AudioKit-Digital-D1-Synth-Privacy-Policy-14dcf6557a088042b2beee2382f5d62f?pvs=4](https://www.notion.so/AudioKit-Digital-D1-Synth-Privacy-Policy-14dcf6557a088042b2beee2382f5d62f?pvs=21) - * NOTE: This app has no official affiliation with AudioKit Pro, LLC. It was built using the free AudioKit source code.

About

Spectrum Synthesizer Bundle

This app provides a bundle of four professional audio unit synthesizers and one effect, inspired by popular eurorack modules. Explore diverse sound design possibilities with multi-mode oscillators, modal synthesis, string generation, and granular sampling. Compatible with DAWs and AU hosts for creative music production.

Highlights
  • Multi-mode polyphonic oscillator
  • Modal synthesis
  • String generation algorithms
  • Granular sampler and looper
  • Modulation LFO and ADSR envelope
  • XY touchpad and modulation matrix
Features
Read full description

Spectrum is a collection of 3 Audio Unit synthesizers and one Audio Unit effect. Spectrum is based on popular eurorack synthesizer modules made by Mutable Instruments. Included are four audio units: Spectrum - Multi-mode 8-voice polyphonic oscillator featuring 14 high quality oscillator algorithms. Supports MPE. Modal - Modal synthesis. Bowed, Blowed, and Struck sounds through a 64-band resonator. Also included as an effect. Resonator - 7 beautiful string generation algorithms. Also included as an effect Granular - Granular sampler, looper, pitch shifter, reverb effect. Note that Granular is an Audio Unit effect, not an instrument, so it goes in an effect slot. To use Spectrum, load the Audio Units in your DAW or AU host of choice, like Audiobus, GarageBand or AUM. Each audiounit also features: - modulation LFO featuring tempo sync, key reset, reset phase adjustment - modulation ADSR envelope - XY touchpad (except on Modal) - 2-source modulation matrix allowing for complex and evolving patches. - MIDI CC control of parameters - Resonator and Modal are also loadable as an AudioUnit effect Spectrum contains DSP code provided under the MIT open source license by Mutable Instruments.

Screenshots

Spectrum Synthesizer Bundle4 screens

Verdict

The call

The clearest difference is in-app purchases: Spectrum Synthesizer Bundle at none against AudioKit Digital D1 Synth's 6. Spectrum Synthesizer Bundle also leads on ads (none vs shown) and review sentiment (93% vs 76%). AudioKit Digital D1 Synth's advantage is ratings volume (2.1K vs 135). On price, rating and update cadence 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

Both are free to download. AudioKit Digital D1 Synth sells 6 in-app purchases, starting at $4.99 per 7 days. Spectrum Synthesizer Bundle asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.8 for AudioKit Digital D1 Synth against 4.8 for Spectrum Synthesizer Bundle. That said, the two scores are not equally well evidenced: AudioKit Digital D1 Synth has 2.1K ratings behind it against 135, so its average is the more settled of the two. Written reviews are what separate them: 76% of AudioKit Digital D1 Synth's written reviews are positive against 93% of Spectrum Synthesizer Bundle's.

UpkeepUpdate frequency

AudioKit Digital D1 Synth ships an update every 3 weeks, Spectrum Synthesizer Bundle every 4 weeks. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

Scorecard7 real differences · 3 level
AudioKit Digital D1 Synth versus Spectrum Synthesizer Bundle: the parameters behind the verdict, then further details
ParameterAudioKit Digital D1 SynthSpectrum Synthesizer Bundle
PriceFreeFree
Rating4.8 (2.1K ratings)4.8 (135 ratings) — better
Positive reviews76.1% of reviews92.9% of reviews — better
Number of ratings2.1K — better135
Update frequencyEvery 3 weeks — betterEvery 4 weeks
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationSubscriptionPaid — better
DevicesiPadiPhone, iPad, iPod — better
Requires iOS13.011.0 — better
Further details — not scored
Size636 MB13 MB
Age rating4+4+
DeveloperAudiobus Pty LtdThomas Burns

Customer experience

AudioKit Digital D1 Synth

All ratings2,007 ratings
Positive95.4%
Neutral1.7%
Negative2.9%
Written reviews243 reviews
Positive76.1%
Neutral7.4%
Negative16.5%

Spectrum Synthesizer Bundle

All ratings135 ratings
Positive95.6%
Neutral1.5%
Negative3.0%
Written reviews70 reviews
Positive92.9%
Neutral0.0%
Negative7.1%

User reviews

AudioKit Digital D1 Synth

From 2.1K App Store ratings

What we love

  • 🎨 Excellent sound quality
  • 🎹 Versatile and inspiring presets
  • 👍 Intuitive and user-friendly interface
  • 💰 Great value for the price
  • 🔥 Cutting-edge digital synthesis

Room to improve

  • 🐛 Occasional crashes and stability issues
  • 🔋 High battery consumption
  • 🔒 Lack of Audio Unit (AUv3) support
  • 🤔 Some presets not easily usable
  • 🕰️ Slow loading times in certain DAWs

Spectrum Synthesizer Bundle

From 135 App Store ratings

What we love

  • ✨ Incredible sound quality
  • 🎶 Deep modulation capabilities
  • 💡 Distinct and unique character
  • 🌊 Excels at fluid soundbeds
  • 🎹 Great for MIDI keyboard use

Room to improve

  • 🐛 Crashes more than it should
  • ⚠️ Description misleading (granular synth missing)
  • 🐛 Modal synthesizer doesn't work alone
  • 💥 Creates massive feedback on macOS
  • ❌ UI stripped down

Bugs and requests

AudioKit Digital D1 Synth

Reported bugs

4 issues
  • Presets not loading correctly
  • MIDI note dropouts and latency
  • Crashes when used with certain DAWs
  • Compatibility issues with newer iOS versions

Requested features

5 requests
  • Add Audio Unit (AUv3) support
  • Improve MIDI integration and responsiveness
  • Implement a built-in recording/sampling feature
  • Expand preset library with more genres and styles
  • Add more sound design controls and modulation options

Spectrum Synthesizer Bundle

Reported bugs

7 issues
  • Crashes more than it should
  • Modal synthesizer doesn't work on its own
  • Creates massive feedback on macOS
  • Songs won't export from GarageBand iOS when plugin is enabled
  • Lots of crashes since previous update
Show 2 more
  • Formatting is horrible on GarageBand, can't see most parameters
  • Granular only shows up in Audiobus3, but can't be launched

Requested features

6 requests
  • Bring back granular synth or remove from description
  • Create a standalone version
  • Bring back old UI as an option
  • Advanced version with standalone apps, proper GUI, and extensive modulation/control
  • More Mutable ports (Ripples, Stages)
Show 1 more
  • Original Rings in 1 voice/modal mode for bass synth

In-app purchases

6 purchases

AudioKit Digital D1 Synth

Subscriptions4
  • Weekly premium$4.997 Days
  • Weekly premium7 Days trial$4.997 Days
  • Yearly premium7 Days trial$9.991 Year
Show 1 more
  • Yearly premium$9.991 Year
One-time2
  • D1 PCM Expansion-01Free
  • Platinum Expansion PCM EXP-01Free
None

Spectrum Synthesizer Bundle

No in-app purchases

Questions

Is AudioKit Digital D1 Synth free?
AudioKit Digital D1 Synth is free to download, with in-app purchases available.
Is Spectrum Synthesizer Bundle free?
Spectrum Synthesizer Bundle is free to download, with no in-app purchases.
Which has better reviews, AudioKit Digital D1 Synth or Spectrum Synthesizer Bundle?
Spectrum Synthesizer Bundle is rated higher. AudioKit Digital D1 Synth averages 4.8 out of 5 from 2.1K ratings, while Spectrum Synthesizer Bundle averages 4.8 from 135 ratings.
Do AudioKit Digital D1 Synth or Spectrum Synthesizer Bundle have ads?
AudioKit Digital D1 Synth shows ads; Spectrum Synthesizer Bundle does not.
Which is updated more often, AudioKit Digital D1 Synth or Spectrum Synthesizer Bundle?
AudioKit Digital D1 Synth ships an update every 3 weeks, and Spectrum Synthesizer Bundle every 4 weeks. Most recently, AudioKit Digital D1 Synth was updated on November 2, 2026 and Spectrum Synthesizer Bundle on November 3, 2026.

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