Comparison

PolyQuad vs STEM

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

PolyQuad

Create complex analog-style synthesizer sounds using four independent voices. Design each voice with its own oscillator, filter, and envelopes, then combine them in various modes for massive layered textures, polyphonic chords, or unique stereo arrangements. Explore a vast library of presets or build your own from scratch.

Highlights
  • Four independent analog-style voices
  • Multiple oscillator and filter types per voice
  • Dual envelope generators per voice
  • Three voice combination modes (UNI, POLY, 2x2)
  • Extensive LFO modulation capabilities
  • Integrated effects unit (reverb, delay, chorus, phaser, drive)
  • 160 factory presets and user preset management
Features
Read full description

PolyQuad is one synthesizer built from four complete voices — and the instrument is what they make together. Each of the four channels is a full analog-style voice: its own oscillator, its own resonant filter, its own envelopes, its own amplifier, its own place in the stereo field. Design each channel for a role — a sub, a body, a sparkle, a slow swell — then play them as one. Three voice modes decide how they combine. UNI stacks all four on every note for one massive layered sound. POLY spreads chords across the channels, so every note of a chord lands on its own instrument. 2×2 plays note pairs on matched couples. Add glide, retrigger control and detune spread on top. THE CHANNELS - Four oscillators: triangle, sawtooth, pulse with PWM, sine — per channel, with octave and fine tune - Four resonant filters with envelope amount and FM depth per channel - Two envelopes per channel (filter and amp), each with three time ranges from snappy to minutes-long - Per-channel VCA with velocity amount and curve, level, pan, AUX send, solo and mute - Per-channel oscilloscope displays, and keys that light up with the voice that took them MOTION - Four LFOs with five shapes, routed to pitch, pulse width, filter FM, resonance, amplitude, pan or send - Each channel decides how much modulation to accept — one LFO can wobble one channel and leave another still - One effect unit — reverb, delay, chorus, phaser, drive — fed by per-channel AUX sends with a master return PRESETS - 160 factory presets in eight categories: Pads, Keys, Strings, Bass, Lead, Drone, Texture, Percussion - Every preset uses the four channels as four different instruments — layered stacks, rotating timbres, per-drum kits - Channel presets: capture one channel's design and load it into any channel of any patch - Your presets are plain JSON files in the Files app — back them up, share them, drop new ones in IN THE STUDIO - AUv3 instrument for AUM, Drambo, Logic Pro, GarageBand and other hosts - MIDI 2.0 with 16-bit velocity; MIDI 1.0 hosts are translated automatically - Every knob on the panel is a host parameter — full automation and session recall - Standalone app with keyboard, so it plays on its own too No account, no ads, no tracking, no network. Your sounds stay on your device.

About

STEM

Features
Read full description

Plug in your audio interface, start the record, and the vocal is on its own fader. STEM splits what is playing — or what is coming in from your mixer — into vocals, drums, bass and everything else, live, on your iPad or iPhone. Each stem lands on its own pair of hardware outputs, so your desk does the mixing. No upload. No render queue. No waiting for a track to be analysed before you can play it. LIVE IN, STEMS OUT Feed STEM from your interface — a turntable through your mixer, a booth output, an instrument — and it separates what is coming in, with the engine aimed at a live source instead of a file. The mix you did not make, taken apart. EVERY STEM ITS OWN OUTPUTS Each stem takes its own pair of hardware channels — vocals to 3-4, drums to 5-6 — up to 16 channels, assigned in a routing matrix that remembers each interface. Outputs start muted until you confirm the routing, because a misrouted stem into a PA is the mistake worth preventing. On a device alone the four stems fold down to stereo, and the console says so. TWO DECKS, ONE CROSSFADER One setting runs a second deck: its own separation engine, its own four stems, its own routing. A crossfader between them, constant-power or cut. HANDS ON THE HARDWARE Map any MIDI CC by tapping a control and moving the knob. Soft takeover means a hardware fader never makes the mix jump, and positions are sent back, so motorised faders and LED rings follow the console. A CONSOLE, NOT A DIALOG Long-throw faders with a 0 dB detent, mute and solo per stem, LED metering, a master strip with BS.1770 loudness. Per-stem three-band EQ and a resonant filter — ladder or state-variable, your choice. Cue any stem to a headphone pair before you bring it up. Save the whole desk as a scene and recall it. SENDS, INSIDE OR OUT Up to four stereo sends, each per stem and post-fader. Send one to a hardware pair for your outboard, or to the built-in tempo-synced delay or plate reverb. STEMS WHILE IT PLAYS Load a track and it comes apart as it plays. Seek anywhere and the stems follow, because the separation is happening now rather than being read from a file somebody prepared earlier. TAKE THE STEMS WITH YOU Write a loaded track back out as four 24-bit WAV files, latency-compensated so they sit at zero in a DAW, rendered by the larger offline model. MEASURED, NOT QUOTED Latency, load and real-time margin are read from the running session and shown while you work. The app never displays a number it has not measured. iPad, iPhone AND Mac Use the console in portrait or landscape on iPad and iPhone. The same app also runs on Apple-silicon Macs. Real-time performance depends on your device and session settings. PRIVACY No accounts, no analytics, no network. Your music never leaves the device. AUV3 PLUG-IN — Load STEM as an effect in AUM: audio in, the remix on the first bus and each stem on its own bus. In a host with one output, such as GarageBand, the first bus plays the remix. PREVIEW AUDIO “Rooted In Peace” by Admiral Bob (ccMixter), with “In Peace” by snowflake. CC BY 3.0. Excerpted and processed by STEM. ccmixter.org/files/admiralbob77/33646 · creativecommons.org/licenses/by/3.0/

Screenshots

PolyQuad4 screens
STEM4 screens

Verdict

The call

The clearest difference is price: PolyQuad at $6.99 against STEM's $14.99. PolyQuad also leads on update cadence (every 2 weeks vs monthly) and iOS requirement (17.0 vs 26.0). On ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

PolyQuad costs $6.99 and STEM $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

PolyQuad ships an update every 2 weeks, STEM monthly. The most recent releases landed on October 31, 2026 and October 29, 2026 respectively.

Scorecard3 real differences · 6 level
PolyQuad versus STEM: the parameters behind the verdict, then further details
ParameterPolyQuadSTEM
Price$6.99 — better$14.99
Rating5.0 (3 ratings) — better—
Number of ratings3 — better—
Update frequencyEvery 2 weeks — betterMonthly
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.0 — better26.0
Further details — not scored
Size4 MB283 MB
Age rating4+4+
DeveloperLASZLO DOBROVOLSZKIMichael Ivertowski

In-app purchases

None

PolyQuad

No in-app purchases

None

STEM

No in-app purchases

Questions

Is PolyQuad free?
PolyQuad costs $6.99, with no in-app purchases.
Is STEM free?
STEM costs $14.99, with no in-app purchases.
Do PolyQuad or STEM have ads?
Neither PolyQuad nor STEM shows ads.
Which is updated more often, PolyQuad or STEM?
PolyQuad ships an update every 2 weeks, and STEM monthly. Most recently, PolyQuad was updated on October 31, 2026 and STEM on October 29, 2026.

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