# Round Trip Latency Meter — Test real-world audio latency

> Measures real-world audio system round trip latency on iOS devices. (iPhone/iPad app by ONYX Apps.)

- Source: https://appshunter.io/ios/app/round-trip-latency-meter/id1427507645 (this page in markdown: same URL + `.md`)
- Developer: [ONYX Apps](https://appshunter.io/developer/356553882)
- Category: Music, Utilities
- Price: $9.99
- Rating: 1.00/5 from 1 App Store ratings · 4 written reviews indexed
- Age rating: 4+
- Requires: iOS 18.0 · 4 MB
- Released: 2018-08-24
- Data updated: 2026-08-21
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/round-trip-latency-meter/id1427507645/reviews.md

## What is Round Trip Latency Meter?

>>> Check out the demo videos at onyx3.com/LatencyMeter

LatencyMeter app measures the real-world Round Trip Latency (RTL) of a given iOS audio system*. It functions by playing short test tones while simultaneously recording (listening for) the tones to return back to the input. This technique requires patching a loopback cable between audio system’s input and output. 

(* iOS audio system here refers to the combination of an iPhone/iPad paired with particular external audio interface)

## Key features

- Measures real-world round trip audio latency
- Plays test tones
- Records returning tones
- Requires loopback cable connection
- Tests iOS audio systems

## Chart rankings

- #196 in Top Paid · Music (US App Store)

## Recent user reviews (4 of 4)

All indexed reviews: https://appshunter.io/ios/app/round-trip-latency-meter/id1427507645/reviews.md

### 1/5 — Won’t work on newer my iPad ios 26

*2025-10-25*

Would have been nice to know that before purchasing.

### 1/5 — Does not work on iOS 14+ or w/ AirPlay

*2023-01-04*

I tried to use this app to test a latency delay I was encountering in my Airplay 2 setup (as it would be perfect for that) but found that even after trying it on my older iPhone, it was still incompatible with iOS 14+. Paid $9.99 in hopes in would help me find whatever this dreaded RTL is but to no avail.

### 1/5 — 用不了

*2022-07-19*

不能使用

### 1/5 — 1

*2020-12-22*

用不了

## Frequently asked questions about Round Trip Latency Meter

### What is Round Trip Latency Meter used for?

Round Trip Latency Meter is used to measure the real-world round trip latency of an iOS audio system. This helps users understand the delay in their audio setup.

### How does Round Trip Latency Meter work?

It plays short test tones and simultaneously records the tones as they return to the input. This process requires a loopback cable to connect the audio system's input and output.

### What hardware is needed to use Round Trip Latency Meter?

You will need a loopback cable to connect the input and output of your audio system. The app is designed to work with iPhones and iPods paired with external audio interfaces.

### What iOS devices are supported by Round Trip Latency Meter?

The app supports iPhones and iPods. It is designed to test the audio system combination of these devices with particular external audio interfaces.

### Is Round Trip Latency Meter free to use?

No, Round Trip Latency Meter is a paid application. It is available for purchase at $9.99.

### How often is Round Trip Latency Meter updated?

The latest version is 1.0.5, last updated on April 18, 2026. The app was originally released on August 24, 2018.

### What is the age rating for Round Trip Latency Meter?

Round Trip Latency Meter has an age rating of 4+. This indicates it is suitable for a wide range of users.

### Does Round Trip Latency Meter have ads?

No, Round Trip Latency Meter does not contain advertisements. It is a paid application without any ad interruptions.

## Version history (last 4 releases)

### 1.0.5 — 2026-04-18

- Fixes a bug where buffer sizes were not set correctly on iOS 18

### 1.0.3 — 2023-10-09

- Updated to comply with App Store requirements

### 1.0.1 — 2018-11-15

- Fixed mic permission issue with iOS 12

### 1.0 — 2018-08-23

No release notes.

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## More apps by ONYX Apps

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All apps by ONYX Apps: https://appshunter.io/developer/356553882

## Related topics

[latency](https://appshunter.io/ios/topics/latency)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-21.*