METRONAUT is a revolutionary app that will empower you to play any instrument – including your voice – as if you had a real orchestra in your living room to accompany you.

Do you practice often?

Do you enjoy pushing your boundaries?

Do you want to craft your interpretation freely?
Do you play a rare instrument?

Did you just start as a singer?

Are you a music teacher?

Then Metronaut is your ideal musical companion!


Our app enables you to be accompanied by professional musicians, regardless of your skill level or instrument. Metronaut listens to you in realtime and adapts accompaniment data to your speed, position, rhythm, performance and voice. This is done thanks to our unique machine listening capabilities as a result of 8 years of intense R&D at Ircam Labs in Paris.

NOTE: Metronaut is free to download and offers 10 minutes of free play time every month. To enjoy unlimited play time, subscribe to Metronaut Premium (weekly or monthly plan).
Payment will be charged to iTunes Account at confirmation of purchase. Subscriptions automatically renew unless auto-renew is turned off at least 24-hours before the end of the current period, by going to the user’s Account Settings after purchase. Payment will be charged to iTunes Account within 24-hours prior to the end of the current period. Any unused portion of a free-trial period, will be forfeited when the user purchases a subscription.


Metronaut’s accompanists are among the best orchestras and pianists. Each accompaniment offers fully acoustic and high quality studio recordings. You can adjust its tempo without impairing sound quality.

If you play music mainly as a hobby, Metronaut will help improve your level, as if musicians were standing by your side. You can play any piece you wish, at your rhythm, freely. And this at the original tempo, or at any other tempo you want.

Aside from playing the instrument per se, nothing is harder than keeping up with the right tempo. Note after note, Metronaut’s "Tempo Regulator" feature will draw you towards that comfortable tempo you had initially set.

Get empowered to play at your own rhythm throughout the piece: Metronaut adapts accompaniment tempo to your interpretation in real-time.

You can transpose any piece for your voice or instrument: baritone for a soprano, violon for a clarinet… Whether you want to play a classical piece with a rare instrument or with another instrument than the one originally intended, or sing outside of your voice range, you will enjoy just the right transposition.

Metronaut leverages music scores to the digital age: setting the tempo down to the very beat, a score scrolling as you play, selecting where to start down to the very note, choosing clefs, transposing for different instruments or voice ranges… All meant to empower you to perform under the best possible conditions.

Metronaut provides everything you need to make more progress and avoid bad habits: Record and listen to the piece you just played while following your performance on the score. A difficult part to play? Select and play it in loop until you get round the cape. You can also tune your instrument to your ideal pitch, annotate your score... And listen to other interpretations! Use all the data and statistics you need to track your practice frequency and thus optimize your work.

Metronaut's catalog expands by you and for you: upvote pieces suggested by other users and suggest your own new pieces!
You can also make audio or video recordings of your performances and share them to help other musicians.


What’s New

Version 3.3.1

As one says, honesty is the most important thing in a relationship. Well to be honest, we had a teeny tiny bug going on with the App memory…
As a sorry and demonstration of our love, here’s a brand new version with it fixed ;)
Send us your comments and suggestions to and if you like the App, rate us on the AppStore!

Ratings and Reviews

3.5 out of 5
88 Ratings

88 Ratings

Huskrred ,

Switch to subscription model bad move

Edit: I’m changing my rating from 1 to 3 stars because the app itself is great, and the developer is very responsive, which is a great attribute. I can’t go higher than 3, though, because the nickel-and-diming of a hundred services is not good, and I can’t support that.

Well, so much for that. I had built up some nauts to “purchase” some music... and TODAY they switched the app to a subscription-based model, so I lost all the virtual money I had saved up. 10 lousy minutes per month for free, and then you have to pay for more? No thanks. I had just raved about this app earlier this week to an Orchestra I play with and shared on Facebook LAST NIGHT! They all LOVED the idea of a reward-based system instead of subscribing like other apps. Now I have to recant my endorsement and delete my Facebook post because I don’t share something I’m not excited about. I don’t do subscription services like this because eventually you’re spending a lot of money per month with multiple services. You don’t notice it when you sign up... just when all the bills come. I really liked this app, too. I’m disappointed.

Developer Response ,

Hi there,
We know that switching Metronaut to a freemium model with subscriptions is a big change for musicians who used the free version of the App before and we understand your frustration about the Nauts you had previously saved up. We're sorry you're disappointed and we loved the reward-based system as well, however this model wasn’t sustainable for the App both to be maintained to its current performance standard and to keep growing (catalog- and feature-wise). To ease this transition for our former users we are offering you 1 month free premium subscription with unlimited access to all pieces of the catalog. If you have further questions don’t hesitate to write us to !

bpladdict020 ,

Fantastic idea, needs a lot of work

I am a cello performance major, and when I came across this app I thought it was a genius idea. I downloaded it and found the concerto I am working on (Elgar) but I was disappointed to find that the solo part was a measure ahead the accompaniment throughout the majority of the piece. I was also saddened to find only 3 cello concertos (all of the movements were separate, maybe lump them together?) but I hope more are added with time. While I understand the need to entice casual musicians with fun arrangements of pieces like Clair de Lune and the Moonlight sonata, I think they should shift their focus to serious musicians because we will be the ones using this app the most religiously. For that to happen, there needs to be a lot more concertos and sonatas added. I honestly see this app becoming a popular practice tool, but for now a lot of work and a shift in focus is needed for it to get there.

Developer Response ,

The Elgar concerto problem is now fixed! Thanks for reporting and sorry we missed this. Here is a bonus:

Thanks also for your suggestions on our Catalog Policy. We actually have more “advanced pieces” today than “Moonlight Sonata arrangements”. :) But we get comments on both sides.
We have restarted our catalog production now and we are doing both. If we get more support from the professional body of musicians, we can definitely put more focus on that part.

Do not hesitate to let us know how we can improve the App! Reviews from users like you mean a lot to us and we really hope to see more and reach out to more musicians like you.

Any suggestions?

JapaneseTeacher ,

The closest thing available to playing music with others

I play with an orchestra. There is nothing like that magic when we are all on the same wavelength and join tempos without saying a word. But when we use an accompaniment track, it is always dead, somehow.

Until now. Having dynamic accompaniment through Metronaut unlocked something in my playing. Especially being able to use it while alone in my room and with/without headphones, it allowed for experimentation and the ability to comfortably play at any dynamic. I discovered a whole new style for when I play the viola. This interplay between my playing and Metronaut helped me internalize the music at lightning speed. I remember how it felt to play after I was done.

I highly recommend this app for all classical musicians, period!


216.2 MB

Requires iOS 10.3 or later. Compatible with iPhone, iPad, and iPod touch.


English, Dutch, French, German, Italian, Japanese, Korean, Polish, Portuguese, Russian, Simplified Chinese, Spanish, Swedish, Thai, Traditional Chinese, Turkish, Ukrainian

Age Rating
Rated 4+
In-App Purchases
  1. Monthly Subscription $9.99
  2. Weekly Subscription $3.99
  3. Monthly Subscription $9.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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