reTONE: A Free App That Turns an Old Android Phone Into a Dedicated Music Player

There is a decent chance you have one in a drawer: an Android phone two or three generations old, battery still holding a charge, and — if it is old enough — a 3.5mm headphone jack on the top edge. A Japanese audio importer has spent the autumn turning that drawer phone into something with a job again.

The app is called reTONE, it is made by Iida Piano Co., Ltd., and it is free, with no advertising and an optional donation to the developer. It converts an Android handset into a dedicated music player: its own audio engine, its own file handling, and an option to take over the home screen and lock screen so the phone stops behaving like a phone. On 4 November the developer's site posted a notice saying reTONE is now on Google Play — the peg for this story, and the point at which a viral side project became something anyone can tap to install.

Who is behind it

Iida Piano is not a software house. It is an audio importer and distributor with its own headphone brand, KuraDa; Phile Web reports that the company also imports Camerton and has recently begun importing Michell turntables. In an interview with the Japanese site, Iida Piano's Mr Iida framed reTONE as something made because he wanted it to exist rather than as a commercial product.

The timeline has been brisk. A prototype was shown at Potafes Osaka on 3 October. Iida Piano announced the app on X on 18 October, and the reaction was strong enough that the beta APK, originally planned for November, was published on the official site on 23 October instead. By 26 October downloads had passed 10,000, according to BCN+R citing the company. By 3 November the original X post had drawn more than 640,000 impressions, 2,000 reposts and 7,000 likes, per Phile Web. On 7 November, real phones running the app are due to be shown at the Autumn Headphone Festival 2026.

What it actually does

The requirements are deliberately low: Android 4.0 or later on an ARM processor, 32-bit or 64-bit, with no root access and no custom ROM needed. That is a wide net, and it is the whole point — the target device is a handset too old to be a daily driver.

Once installed, reTONE can run as the home screen and lock screen, and a dedicated mode mutes notifications, ringtones and alarms so nothing interrupts playback. Music lives in the phone's Music folder. The app plays FLAC, WAV, AIFF, ALAC and DSD — DSF and DFF, DSD64 through DSD256, per the developer — using its own decoding engine, which means it can handle formats the host phone's own software cannot read.

The more interesting claim is on output. reTONE sends FLAC at up to 24-bit/192kHz directly to a USB DAC, bypassing Android's own audio path, on USB Audio Class 2 devices; this is stated by both the developer and AV Watch. Sample-rate conversion, where it is needed at all, happens at most once. For anyone who has fought with Android's resampling behaviour, that is the headline feature rather than the format list.

There are a couple of extras. A second Android phone running reTONE can act as a Bluetooth remote — useful if the player phone is parked next to a DAC and an amplifier rather than in a pocket. The app can also pull files from a home NAS over DLNA. Network features are switched off by default, and the developer states that the app collects no user data.

Streaming is not part of the plan

Iida Piano has been explicit that reTONE is for files you own. The company has said on X that streaming is left to each service's own app. That is a clear scope decision rather than an omission, and it shapes who the app is for: people with a ripped or downloaded library, a USB DAC or a pair of headphones, and a spare handset.

Installing it

On phones that have the Play Store, the developer's site says reTONE can now be installed from Google Play. We were not able to locate the listing independently, so take that as the developer's statement rather than a verified fact. On older handsets without Play services, the route is the beta APK copied across over USB from a computer. We are not in a position to offer any assurance about sideloading an APK; that is a decision each reader makes for themselves. The app also remains in beta.

What we are not saying

No one on this desk has heard reTONE. Phile Web's reporter compared the app running on Sony, Kyocera and LG handsets and described hearing differences between them, but that is one reporter's listening impression on specific hardware, not a measured result, and we are not extending it into a verdict. An interview remark about the engine reaching DXD is likewise unofficial and should not be read as a published specification.

It is also worth noting how little English-language coverage exists. As of 4 November 2026 the only English material we could find was the developer's own site; the reporting is Japanese, with one French write-up at Clubic. There is no iPhone version in any source, and Clubic notes the remote function does not work with an iPhone. Whether reTONE grows beyond a Japanese enthusiast story may depend on what the Google Play listing does next.

For a category that usually answers "I want a dedicated player" with a purchase, an app that costs nothing and runs on hardware already sitting in a drawer is an unusual proposition — and the 10,000 downloads in three days suggest a fair number of people were waiting for it.