Comparison

isfizz vs Spindles

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

Head to head
About

isfizz

This app plays SFZ files, an open format for sampled sound instruments. It supports various audio file formats, MIDI, and Scala tuning files. It also functions as an Audio Unit Extension (AUv3) for use with other music apps.

Highlights
  • SFZ file playback
  • Audio Unit Extension (AUv3) support
  • Edit SFZ strings
  • Load SFZ files in place
  • Scala tuning file support
  • MIDI support
Features
Read full description

isfizz is a SFZ file player. SFZ is an open text format for sampled sound instruments. This app can load SFZ and play the instrument. - Includes Audio Unit Extension (AUv3). - You can edit SFZ string. - The app loads SFZ files in place without copying the files. - Double tap to enter the value, triple tap to reset. - Supports Scala tuning files (.scl). - Supports MIDI. - Supports 16 out. use the "output=N" opcode in SFZ. Supported sample file format: - .wav (raw PCM) - .aiff - .mp3 - .flac - .ogg (vorbis) - .wv (wavpack) This app is an iPhone/iPad port of sfizz-ui project. The app is made from some sfizz-ui codes and images. About half of the income from this app will be donated to SFZ Tools team. This app and the description contain machine translated text.

About

Spindles

Experience a curated sound environment designed for sleep, focus, and calm. Featuring analog music, soundscapes, and auditory patterns, it supports gradual transitions and sustained states for better rest and reduced anxiety. Enjoy a refined listening experience with intelligent playback controls.

Highlights
  • Purpose-composed analog and acoustic music
  • Immersive soundscapes
  • Gentle auditory patterns
  • Supports sleep, focus, and calm
  • Gradual transitions and sustained states
  • Intelligent playlist flow
  • Flexible playback controls
Features
Read full description

Created by Dudadius—composer Bryan Rheude—Spindles is original music and handcrafted sonic environments for focus, sleep, calm, and movement. Acoustic piano, analog and modular instruments, field recordings, custom noise, and binaural sound are composed and shaped by hand. Research informs the craft. The music leads. TODAY’S ATMOSPHERES Four fresh daily starting points—Mellow Focus, Beat Focus, Sleep, and Soothe. One tap to begin in the app or from a Home Screen widget. FOCUS COLLECTION Three paths into sustained attention: expansive Harmonic Fields, evolving Melodic Focus, and rhythmic ADHD Beats. SLEEP SPINDLES A guided journey through Fall Asleep, Stay Asleep, and an optional Wake Transition. Choose your own combination or begin with today’s rotating selection. EXPLORE Browse by state, sound, or intention—from acoustic piano and natural environments to custom noise, binaural sound, meditation, movement, and more. 14 DAYS OF FULL ACCESS Create a free profile and listen for 14 days. No payment information is required. Subscription options appear only after the trial ends. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

isfizz4 screens
Spindles4 screens

Verdict

The call

The clearest difference is price: Spindles at Free against isfizz's $2.99. Spindles also leads on rating (5.0 vs 4.7) and update cadence (every 5 days vs fortnightly). isfizz's advantage is in-app purchases (none vs 5) and iOS requirement (15.0 vs 18.0). On review sentiment, ratings volume, ads and device support 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

Spindles is free to download; isfizz costs $2.99 up front. Spindles sells 5 in-app purchases, starting at $6.99 per month. isfizz asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Spindles holds the better App Store score, 5.0 against 4.7. Both are backed by a comparable volume of ratings — 14 and 10 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

UpkeepUpdate frequency

isfizz ships an update fortnightly, Spindles every 5 days. The most recent releases landed on September 19, 2026 and September 12, 2026 respectively.

Scorecard6 real differences · 4 level
isfizz versus Spindles: the parameters behind the verdict, then further details
ParameterisfizzSpindles
Price$2.99Free — better
Rating4.7 (14 ratings)5.0 (10 ratings) — better
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings14 — better10
Update frequencyFortnightlyEvery 5 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better18.0
Further details — not scored
Size6 MB26 MB
Age rating4+4+
DeveloperRyouta KiraRedsquared Inc

Customer experience

isfizz

All ratings14 ratings
Positive92.9%
Neutral0.0%
Negative7.1%
Written reviews6 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Spindles

All ratings10 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews7 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

isfizz

No in-app purchases

5 purchases

Spindles

Subscriptions4
  • Individual Renews Monthly$6.991 Month
  • Family Access Renews Monthly$10.991 Month
  • Individual Renews Annually$69.991 Year
Show 1 more
  • Family Access Renews Annually$110.991 Year
One-time1
  • Lifetime Access to Spindles$299.99

Questions

Is isfizz free?
isfizz costs $2.99, with no in-app purchases.
Is Spindles free?
Spindles is free to download, with in-app purchases available.
Which has better reviews, isfizz or Spindles?
Spindles is rated higher. isfizz averages 4.7 out of 5 from 14 ratings, while Spindles averages 5.0 from 10 ratings.
Do isfizz or Spindles have ads?
Neither isfizz nor Spindles shows ads.
Which is updated more often, isfizz or Spindles?
isfizz ships an update fortnightly, and Spindles every 5 days. Most recently, isfizz was updated on September 19, 2026 and Spindles on September 12, 2026.

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