JamEngine vs ZZZ Polyrhythm

JamEngine is a real-time music generation app that puts a full backing band in your pocket. Choose from 15 musical styles, pick your key and tempo, and JamEngine instantly creates authentic, genre-appropriate arrangements, complete with MIDI drums, bass, guitar, piano, brass, and woodwind instruments. Whether you're a guitarist looking for a rhythm section to practice over, a songwriter sketching out chord progressions, a jazz player working on improvisation, or a producer hunting for inspiration, JamEngine gives you a responsive, endlessly variable musical companion. 15 STYLES TO CHOOSE FROM Rock · Hard Rock · Classic Rock · Metal · Pop · Ballad · Blues · Slow Blues · Jazz Swing · Jazz Ballad · Funk · Bossa Nova · Reggae · Country · Lo-fi Each style comes with genre-authentic drum patterns, bass lines, guitar voicings, keyboard parts, and horn arrangements. 12 INSTRUMENTS Build your arrangement from a roster of 12 instruments, each with realistic General MIDI sounds: • Drums · Bass · Electric Guitar · Acoustic Guitar • Piano · Organ · Strings • Trumpet · Trombone · Alto Sax · Tenor Sax · Clarinet Mix and match any combination. Each instrument has independent volume, mute, solo, pan, density and 11 variation levels to control the complexity and character of its part. SMART CHORD PROGRESSIONS Build chord progressions using the grid editor or the interactive Circle of Fifths, a visual tool that highlights diatonic chords in your selected key, so you can see at a glance which chords belong together. Start from scratch, or load one of the built-in templates: I-IV-V, I-V-vi-IV, ii-V-I, 12-Bar Blues, Jazz Turnaround, and more. Choose from 18 chord types including major, minor, seventh, diminished, augmented, sus, and extended chords. FLEXIBLE TIME & KEY Play in any of 7 time signatures, 2/4, 3/4, 4/4, 5/4, 6/8, 7/8, and 12/8, with BPM from 40 to 300. Tap tempo to match a song. Select any of the 12 keys in major or minor. Change key mid-session and your chord progression transposes automatically to preserve harmonic relationships. VARIATION RANDOMIZER Enable the variation randomizer and JamEngine will shuffle instrument variations at musically appropriate boundaries, every 4 or 8 bars, keeping your practice sessions fresh and unpredictable without you lifting a finger. EXPORT YOUR SESSIONS Capture your jam as a WAV, M4A, or multitrack MIDI file. Use export to bring your arrangements into your DAW for further production. SONGBOOK Save your favorite sessions, style, key, tempo, chord progression, and instrument setup to your personal Songbook. Load them instantly to pick up where you left off. CUSTOM SOUNDFONTS Import your own SF2 SoundFont files to customize the sound of every instrument. FREE TO START, PRO TO UNLOCK EVERYTHING JamEngine is free with 4 styles (Rock, Metal, Jazz Swing, Lo-fi), 3 song saves, and all playback features. Upgrade to JamEngine Pro for a one-time purchase to unlock all 15 styles, unlimited song saves, and full export capabilities.

Zzz Polyrhythm is a polyrhythm-focused metronome that lets you layer multiple rhythms simultaneously for advanced rhythmic practice. From classical 2-against-3 to jazz shuffle to contemporary 7-against-11 — instantly build any rhythm pattern you can imagine and play it back with professional-quality voices. Key Features [Base Beat — the time-keeper] - Time signature: any numerator (1-16) and denominator (2 / 4 / 8 / 16) - BPM: precise control from 30 to 240 - Tap Tempo: detect any tempo in real time - 8 voices: Wood Block / Click / Cowbell / Sine / Square / Tick / Hi Click / Low Thud [Layered Rhythms — Overlay] Layer additional rhythms on top of the base beat to construct complex polyrhythms. - Starting beat: not only "beat 1, beat 2" but also fractional positions like "beat 1.5" - Length: whole / half / quarter / eighth / sixteenth / thirty-second note × none / dotted / double-dotted - Subdivisions: any tuplet from 2 to 11 - Shuffle mode: play only the first and last clicks for a jazz swing feel - Timing offset: slide the start/end positions back and forth to fine-tune swing - Voice: choose an independent voice for each overlay from 8 sound presets [Visualizer] Concentric ring display lets you see rhythm timing at a glance. A dot lights up the moment each click fires, helping you grasp polyrhythm structure visually. [Presets] (Premium) Save your favorite rhythm configurations with custom names. Recall with one tap. Browse multiple presets and switch any time. [Phase-preserving BPM changes] Change BPM in the middle of a beat — the rhythm doesn't reset, it smoothly accelerates or decelerates, just like a professional studio metronome. Who it's for - Drummers / percussionists training complex rhythmic sense - Jazz / fusion players developing swing feel - Instrumentalists practicing 3-, 5-, 7-tuplet figures - Composers / arrangers analyzing multi-voice rhythm relationships - Performers studying traditional cross-rhythms and contemporary music Languages 日本語 / English / 中文 / 한국어 / Español / Português Switch languages manually from the hamburger menu, or have the app follow your device's system language. Free vs Premium [Free] - Base beat + up to 2 overlay layers - All 8 voices / any time signature / BPM 30-240 - Tap Tempo / Shuffle / full feature access - Discreet banner ad + occasional interstitial [Premium (Ad-free)] - All ads removed - Add 3 or more overlay layers (unlimited) - Save / load / delete rhythm presets Subscription Details - Title: Premium (Ad-free) - Length: 1 month, auto-renewable - Price: 180 JPY / month Payment will be charged to your Apple ID account at confirmation of purchase. The subscription renews automatically unless it is canceled at least 24 hours before the end of the current period. Your account will be charged for renewal within 24 hours prior to the end of the current period. You can manage or cancel your subscription anytime in your App Store account settings after purchase. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://smolt-stage.com/home/privacy/zzz-polyrhythm-privacy-policy-ios-en.html Developer SMOLT STAGE, K.K. © 2026 SMOLT STAGE, K.K. For questions and feature requests, please use the in-app feedback form. We hope this contributes to your musical practice.