# Stone Echo vs PO

The clearest difference is review sentiment: PO at 100% against Stone Echo's 50%. PO also leads on price (Free vs $2.99) and rating (5.0 vs 2.8). Stone Echo's advantage is in-app purchases (none vs 3) and ratings volume (4 vs 1). On ads and device support there is nothing between them.

PO is free to download; Stone Echo costs $2.99 up front. PO sells 3 one-off in-app purchases. Stone Echo asks for nothing beyond the download.

PO holds the better App Store score, 5.0 against 2.8. Both are backed by a comparable volume of ratings — 4 and 1 respectively. Written reviews point the same way: 50% of Stone Echo's written reviews are positive against 100% of PO's.

Stone Echo ships an update every 38 months, PO every 2 days. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Stone Echo | PO |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [2.8 (4 ratings)](https://appshunter.io/ios/app/stone-echo/id1354390681/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/po-patchstudio/id6809190034/reviews)** |
| Number of ratings | **4** | 1 |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 38 months | **Every 2 days** |
| Monetization | Paid | **Free** |
| Size | 9 MB | 14 MB |
| Requires iOS | **10.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Aleksandar Mlazev](https://appshunter.io/developer/1093798140) | [Photon Consulting Limited](https://appshunter.io/developer/6778625337) |

## What reviewers say

### Stone Echo

[App page](https://appshunter.io/ios/app/stone-echo/id1354390681)

This app creates a unique echo effect with adjustable frequency modulation, inspired by Mayan pyramid acoustics. It offers musical and experimental soundscapes, functioning as a standalone application or an AUV3 plugin.

**Highlights:** Frequency changing echo effect, Phase modulated frequency, Standalone app and AUV3 plugin, Adjustable time, feedback, and level, UFO mode for experimental sounds

**Features:** Vision Pro support

**In-app purchases:** none


### PO

[App page](https://appshunter.io/ios/app/po-patchstudio/id6809190034)

Design and edit drum sounds, kits, and patterns for Teenage Engineering's PO-32 Tonic. Transfer your creations to the device via audio. Back up and edit existing sounds, and import/export patches from Microtonic.

**Highlights:** Shape 16 sounds with 21 synth parameters, Program 16-step patterns with accents, Send kits, sounds, or patterns via audio, Back up and decode PO-32 data dumps, Import/export Microtonic patches, Local library with tags and favorites

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Tip: Thanks | $5.00 | one-time |
| Tip: Big Thanks | $10.00 | one-time |
| Tip: Huge Thanks | $20.00 | one-time |


## Frequently asked questions

### Is Stone Echo free?

Stone Echo costs $2.99, with no in-app purchases.

### Is PO free?

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

### Which has better reviews, Stone Echo or PO?

PO is rated higher. Stone Echo averages 2.8 out of 5 from 4 ratings, while PO averages 5.0 from 1 ratings.

### Do Stone Echo or PO have ads?

Neither Stone Echo nor PO shows ads.

### Which is updated more often, Stone Echo or PO?

Stone Echo ships an update every 38 months, and PO every 2 days. Most recently, Stone Echo was updated on October 24, 2026 and PO on October 25, 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.*