Built for cello practice

Your score.
Your tempo.
Your progress.

ArcoPraxis is dedicated to one thing: helping you practice better. Not a gig app. Not a curated score library. Just powerful tools that turn any sheet music into a personal coach.

Get ArcoPraxis See what's inside
  • iPhone & iPad
  • No ads
  • Pay once
  • Free updates
ArcoPraxis on iPad — score practice with metronome, loop selection, and annotations
ArcoPraxis on iPhone — looped measure practice with tempo, rhythm, and tuner

What ArcoPraxis is — and isn't

This is not another music app you've seen before.

Popular apps are built for gigs, libraries, and browsing thousands of scores. ArcoPraxis is built for you — sitting in the practice room, working on the passage that keeps beating you.

Not this

  • A gig app with setlists and stage mode
  • A curated library of famous scores
  • A social platform for performers
  • Endless subscriptions and upsells

This

  • Your teacher's assignment, ready to practice
  • Your photo, scan, PDF, or MusicXML
  • Loop the hard part until you own it
  • Slow down without destroying the sound

Practice tools

Everything you need to go deep on a passage.

Slow down to any speed — zero distortion

Slow YouTube and the audio turns to mush. ArcoPraxis uses a real cello synthesizer, so you can drop to any tempo and still hear clean, musical pitch. Practice at your speed, not the virtuoso's.

ArcoPraxis tempo settings on iPad — set any BPM from 1 to 200 with subdivision options

Remove the rhythm

Strip away timing to focus purely on intonation. Hit every note in tune before you worry about the beat. Add rhythm back when you're ready to work on shifts and phrasing.

Diagram: notes with mixed rhythms become the same pitches as even quarter notes

Loop mode

Select the measures that haunt you and loop them — over and over and over — until you've mastered them. The practice room's best friend. Works the same on iPhone and iPad.

ArcoPraxis on iPhone with a looped measure selected, reps counter, and practice controls

Tuner & metronome built in

No app-switching mid-practice. Tune up, set your tempo, and stay in the flow — everything lives in one place.

ArcoPraxis on iPad with metronome at 48 bpm, loop tools, and a live tuner reading G

Import anything

Photos, scanned documents, PDFs, MusicXML, and native .arco files — the best format for practice. Your teacher can send you assignments directly in Arco format, ready to load and play.

Photos Scans PDF MusicXML .arco
Add Score dialog with Import Score, Scan Image, Photo, and PDF Score options

Under the hood

The Raisin Bread detection algorithm

No machine learning. No training data. No cloud API waiting on a server halfway around the world. Just clever geometry that finds noteheads the way a human eye does — by asking the right questions in two dimensions.

  • >95% notehead finding accuracy
  • Minimal editing after detection
  • On-device runs entirely on your iPhone or iPad

Like finding raisins in a slice of bread — scan horizontally, scan vertically, and only the objects that pass both tests at the same spot are noteheads. Stems, beams, staff lines, and text fail one test or the other. Noteheads pass both.

Review Scan screen showing detected noteheads highlighted in green on a Vivaldi score
Noteheads found on-device — ready to use or fine-tune
Adjust Staff Lines screen with colored handles aligned to each staff
Staff alignment when a scan needs a nudge

Your practice, your way

One passage. Three modes. Infinite reps.

01

Focus on intonation

Remove rhythm. Hear each pitch clearly. Fix the notes that slip sharp or flat.

02

Work on shifts

Add rhythm back. Now the timing matters — nail the shifts and string crossings.

03

Be a cello hero

Speed it up. Loop it. Push the tempo until the passage feels effortless.

See it in action

Watch the tutorial

A walkthrough of importing a score, slowing it down, looping hard measures, and practicing with the tools built into ArcoPraxis.

Why I built it

YouTube cellists are amazing. They're also way too fast.

I built ArcoPraxis because I was frustrated with YouTube. The cellists on there are incredible — but they play too fast for a beginner. Even when they play slow, it's still too fast.

Slow down YouTube itself and the sound gets super distorted — awful to practice with. And the ads. Holy moly, the ads.

ArcoPraxis lets you slow music playback to any speed with zero distortion. Remove the rhythm to focus on intonation. Add it back to focus on shifts. Speed it up and be a cello hero. It's your call.

And the ads? None. Pay once, play forever. Free updates.

Aaron Celestian

"Even when they play slow, it's still too fast."

This is just the beginning

Loads more features are planned.

ArcoPraxis is actively evolving — new practice modes, smarter editing tools, and deeper intonation feedback are all on the way. Buy once and every update is yours, free.

Interval quizzes Sight-reading mode Live intonation feedback Fingering overlays And more…

Simple pricing

Pay once. Play forever.

No subscriptions. No ads interrupting your practice. No "premium tier" holding features hostage. One purchase, lifetime access, free updates.

  • Full app — no feature gates
  • All future updates included
  • Zero ads — ever
  • On-device recognition — your scores stay private
ArcoPraxis Download on the App Store

Available on iPhone & iPad · iOS 17+

Get in touch

Contact

Questions about practice tools, privacy, or anything else? Send a note — we’ll get back to you. Read the full privacy statement anytime.