# Bookends vs Decibel

The clearest difference is review sentiment: Bookends at 76% against Decibel's 0%. Bookends also leads on ratings volume (400 vs 5). Decibel's advantage is rating (5.0 vs 4.7) and update cadence (every 2 weeks vs every 2 months). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Bookends sells 2 in-app purchases, starting at $14.99 per year and Decibel sells 5 in-app purchases, starting at $9.99 per year. Whichever you choose, the download price is not the number that matters.

Decibel holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Bookends has 400 ratings behind it against 5, so its average is the more settled of the two. Written reviews complicate that: 76% of Bookends's written reviews are positive against 0% of Decibel's, so the app with the better star average is not the one people write more warmly about.

Bookends ships an update every 2 months, Decibel every 2 weeks. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Bookends | Decibel |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.7 (400 ratings)](https://appshunter.io/ios/app/bookends/id739087947/reviews) | **[5.0 (5 ratings)](https://appshunter.io/ios/app/decibel-sound-level-meter/id1624742896/reviews)** |
| Number of ratings | **400** | 5 |
| Positive reviews | **76.4% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 weeks** |
| Monetization | Free with in-app purchases | Freemium |
| Size | 114 MB | 18 MB |
| Requires iOS | 18.6 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Sonny Software, LLC](https://appshunter.io/developer/417583547) | [Sunshine Software Labs](https://appshunter.io/developer/1788219451) |

## What reviewers say

### Bookends

[App page](https://appshunter.io/ios/app/bookends/id739087947)

Manage your research references and PDFs on your mobile device. Search online databases, import metadata, annotate PDFs, and organize your library. Offers basic functionality for free with optional one-time purchase and yearly subscription for advanced features like cloud sync and unlimited imports.

**Highlights:** Search online reference databases, Import metadata and PDFs, PDF annotation and markup, Barcode scanning for references, Cloud sync across devices, Share online libraries, Create multiple libraries

**Features:** Family Sharing, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $14.99 | per year |
| Standard | $14.99 | one-time |

**What reviewers like**

- 🚀 Seamless sync across devices
- 👍 Excellent PDF annotation tools
- 🔒 Reliable and stable
- 💡 Powerful reference management features
- 👍 Responsive and helpful developer support

**What reviewers complain about**

- 🐛 Sync issues with iCloud and PDF files
- 🔒 Subscription model for essential features
- 👎 Outdated and clunky user interface
- 🔒 Limited functionality on iOS without subscription

**Reported bugs**

- Incompatibility with iCloud Optimized Storage
- Unreliable sync between desktop and mobile versions
- Occasional data loss or corruption

**Requested features**

- Nested folders and tags for better organization
- Automatic PDF metadata extraction
- Improved search and filtering capabilities
- Seamless integration with third-party services


### Decibel

[App page](https://appshunter.io/ios/app/decibel-sound-level-meter/id1624742896)

This app provides precise noise measurement with a real-time decibel gauge and a frequency analyzer for detailed acoustic analysis. It tracks minimum, average, and maximum levels, offering historical graphs for sound fluctuations. Ideal for professionals and enthusiasts needing accurate sound monitoring.

**Highlights:** Real-time decibel gauge, Frequency analyzer (Hz), Min/Avg/Max decibel values, Historical decibel graph, Acoustic analysis tool, Environmental noise monitoring

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Get Premium Annual Offer | $9.99 | per year |
| 3 Days Free Trial Weekly VIP | $9.99 | per 7 days |
| Get Premium Monthly | $19.99 | per month |
| 7 Day Free Yearly VIP | $29.99 | per year |
| Get Premium Annual | $49.99 | per year |


## Frequently asked questions

### Is Bookends free?

Bookends is free to download, with in-app purchases available.

### Is Decibel free?

Decibel is free to download, with in-app purchases available.

### Which has better reviews, Bookends or Decibel?

Decibel is rated higher. Bookends averages 4.7 out of 5 from 400 ratings, while Decibel averages 5.0 from 5 ratings.

### Do Bookends or Decibel have ads?

Neither Bookends nor Decibel shows ads.

### Which is updated more often, Bookends or Decibel?

Bookends ships an update every 2 months, and Decibel every 2 weeks. Most recently, Bookends was updated on October 23, 2026 and Decibel on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*