Core Synth Free vs Viking Synth
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Core Synth Free
Create music with a monophonic synthesizer featuring dual oscillators, adjustable filters, and envelope shaping. Explore various wave patterns and octaves to craft unique sounds for live performance or composition.
- Dual overlapping oscillators
- Four wave patterns
- Adjustable low pass filter
- ADSR envelope shaping
- 1 octave keyboard
- Save and load patches
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Get your groove on with Core Synth Free, the definitive monophonic synthesizer for the iPhone and iPod touch. With tons of features packed into a small package, Core Synth is great for live performing. This free app has the following features: - 1 Octave keyboard - Keys light up in different colors when pressed Oscillator Module - Dual overlapping oscillators - Four wave patterns: Square, Triangle, Sawtooth and Reverse Sawtooth * Select from 5 octaves * Adjust glide between notes * Fine tune Oscillator 2 with option to sync with Oscillator 1 Volume Envelope Shaper - Edit ADSR (Attack, Decay, Sustain, Release) Low Pass Filter Module - Adjust Cutoff and Resonance - Edit ADSR (Attack, Decay, Sustain, Release) Upgrade to the full version within the app for the following additional features: - 7 Octave Keyboard - Octave control to move along entire range Patches Module - Save an unlimited number of individually named patches - Browse through your collection before applying patch - Delete unwanted patches - Backup patches via iTunes File Sharing Modulation Module - Four wave patterns: Square, Triangle, Sawtooth and Reverse Sawtooth - Modulate Filter, Pitch or Wave - Adjust LFO Rate and amount Arpeggiator Module - Arpeggio moves up to 5 octaves - Four step modes: Up, Down, Up/Down, Random - Adjust rate Many more exciting enhancements to follow! Core Synth Free includes open source code from MobileSynth developed by Allen Porter.
Viking Synth
This app emulates a classic monophonic analog synthesizer with advanced DSP technology. It features three variable wave oscillators, dual ladder filters, an LFO, and two modulation busses for versatile sound design. An intuitive interface and extensive preset library make it ideal for creating thick bass and rich lead sounds.
- Three continuously variable wave oscillators
- Dual ladder filters (Lowpass/Highpass)
- Multi-wave LFO
- Two modulation busses
- Intuitive user interface with expandable controls
- 228 presets including Bass, Lead, and Synthwave
- State-of-the-art DSP for authentic sound
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Viking Synth is an authentic emulation of a classic monophonic analog synthesizer. It has three continuously variable wave oscillators, two ladder filters with a Dual Lowpass or Highpass/Lowpass configuration, a multi-wave LFO, and two modulation busses. Viking Synth uses state of the art DSP technology to accurately reproduce the sound of the hardware. You get a desktop quality plug-in at an iOS friendly price. Viking Synth is an Audio Unit Extension Instrument (AUv3) that works as a plug-in inside host apps. Just open up your favorite host that supports Audio Unit Instruments and select it from the list of available Audio Units. Compatible with GarageBand, Cubasis, Auria, BeatMaker, AudioBus, AUM, Modstep, and more. The user interface of Viking Synth is designed for quick and intuitive control. Knobs and sliders expand during tweaking and are designed so the current value isn't hidden below your finger. The six pages divide the synth into logical sections that can be accessed quickly. The filter display acts as an XY pad for controlling cutoff and resonance. Simply double tap a knob or slider to reset it to its default value. Presets Viking Synth comes with 228 presets in the categories Bass, Bright Lead, Electro Bass, FX, Percussive Lead, Soft Lead, and Synthwave. The synth excels at thick bass and rich lead sounds. The 50 Electro Bass and 50 Synthwave presets were designed by renowned sound designer eXode. Presets work perfectly with GarageBand, Cubasis, and AUM. Oscillators At the heart of Viking are three adjustable wave oscillators. The continuously variable waveform knob gives the oscillators a unique sound that can’t be achieved with the fixed waveforms found in most synths. A noise oscillator provides three types of noise, one specifically modeled after the hardware. Modulation Two modulation busses and an LFO provide flexible modulation capabilities. All of the options hidden deep in menus on the hardware are immediately accessible with one tap. Filters The filters are classic transistor ladder filters modeled meticulously. Two DSP varieties are available allowing for either reduced CPU load or soft clipping plus three additional overdriven modes. The number of poles is adjustable for a wider range of filter sounds. Compare Viking to other synths: – Viking’s oscillators are free running, not sampled, wavetable based, or generated from a zero point – Viking’s oscillators use advanced techniques to avoid aliasing – Viking’s oscillators have instability, which is controllable through the tuning drift control – Viking’s nonlinear filter uses circuit modeling and provides soft clipping
Screenshots
Verdict
The clearest difference is price: Core Synth Free at Free against Viking Synth's $3.99. Core Synth Free also leads on iOS requirement (8.0 vs 12.0). Viking Synth's advantage is rating (4.7 vs 2.9) and in-app purchases (none vs 1). On review sentiment, ads 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
Core Synth Free is free to download; Viking Synth costs $3.99 up front. Core Synth Free sells 1 one-off in-app purchase. Viking Synth asks for nothing beyond the download.
Viking Synth holds the better App Store score, 4.7 against 2.9. That said, the two scores are not equally well evidenced: Viking Synth has 42 ratings behind it against 8, so its average is the more settled of the two. Written reviews point the same way: 64% of Core Synth Free's written reviews are positive against 69% of Viking Synth's.
Core Synth Free ships an update every 13 months, Viking Synth every 4 months. The most recent releases landed on June 8, 2026 and September 23, 2026 respectively.
| Parameter | Core Synth Free | Viking Synth |
|---|---|---|
| Price | Free — better | $3.99 |
| Rating | 2.9 (8 ratings) | 4.7 (42 ratings) — better |
| Positive reviews | 63.6% of reviews | 69.4% of reviews — better |
| Number of ratings | 8 | 42 — better |
| Update frequency | Every 13 months | Every 4 months — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 8.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 7 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | Core Engine Apps | Blamsoft, Inc. |
Customer experience
Core Synth Free
Viking Synth
Bugs and requests
Core Synth Free
Not enough reviews yet to summarise bugs or requests.
Viking Synth
Reported bugs
6 issues- Presets not showing up
- Presets disappear
- App not showing in AUv3 menu
- Settings not saving after iOS 14 update
- Crashes when opening presets browser
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- Saved presets not loading
Requested features
5 requests- More subtle drive mode
- Categorized preset browser
- Polyphony option
- Dark mode
- More apps from developer
In-app purchases
Core Synth Free
- Full Version Upgrade$0.99
Viking Synth
No in-app purchases









