Comparison

FFT vs Spark

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

Head to head
About

FFT

Analyze audio with high-resolution frequency and amplitude graphs. Features include a signal generator, cursor readouts, and adjustable graph smoothing. Save and export your analysis results.

Highlights
  • High-resolution amplitude vs. frequency graph
  • Built-in low-distortion signal generator
  • Adjustable graph smoothing and decay time
  • Cursor readout for dB and frequency
  • Save and export analysis graphs and data
  • Peak tracking for highest frequency identification
Features
Read full description

FFT is a high-resolution audio analysis tool for the iPhone and iPod touch. It uses the Fast Fourier Transform to analyze incoming audio, and displays a very detailed graph of amplitude vs. frequency. Use this app with the built-in iOS device microphone, or upgrade to our iAudioInterface2 or iTestMic for a complete professional solution. *** Designed for Acoustical Analysis This application has been designed for acoustics work, and so the bins have been normalized to octaves, to get a display that will show a flat line for pink noise. You can control both the level of graph smoothing and decay time, to get as much or as little detail as you require. You can also control the dB resolution of the graph, as well as the frequency range that is displayed. *** Includes Signal Generator Included in this app is the engine from our Generator app, which is a low-distortion, artifact-free signal generator. The signal generator appears as a heads-up display when you tap the icon, so you can see the graph while you adjust the generator. Generate sine waves, square waves (within limits), white noise, and pink noise, optionally in psuedo-balanced mode. All waveforms are generated in real time using high-precision algorithms. *** Cursor Readout Move your finger across the screen to get a cursor to read out exact dB levels and frequencies. *** Touch-GUI Controls Use a vertical pinch-open gesture to expand the dB scale. Use a horizontal pinch-open gesture to expand the frequency scale. *** Graph Smoothing Smooth the graph by octave, 1/3, 1/6, 1/12, or 1/24 octave. Adjust the decay time from 0.5 seconds, for a very fast fluid display, to 8 seconds, or use Peak Hold or Average mode. Average mode is a true equal-weighted average, which can run continuously. *** Peak Tracking Turn on Peak Tracking to have FFT automatically find a label the frequency of the highest peak on your graph. *** Tune the Parameters Set the FFT size from 4096 to 32k points (depending on iOS device) , or select Equal Points Per Octave mode, for high-resolution analysis, even at low frequencies. *** Calibration FFT comes calibrated for the typical iPad, iPod touch, or iPhone microphone, and you can adjust the calibration. Microphone compensation files tailored to each iOS device are automatically applied. *** Save and Recall When your analysis is complete, you can save the graph image to your photo roll to include in a report, or export the data in an XLS file. *** Display Multiple Graphs Show a recalled graph on the screen in a different color. *** Difference Mode Use a stored graph as a baseline that is subtracted from the current graph in real time. *** RTA or FFT? If you are wondering if you should download this app or our FFT app, check out our website, we have a page devoted to this topic. *** Other Audio Apps Also, check out our other great audio and acoustics apps: AudioTools, our premier suite of audio and acoustics analysis apps, SPL, SPL Graph, for recording SPL over time, RTA, RT60, Generator, and Speaker Pop.

About

Spark

This intelligent amp and app combination creates a virtual band that learns your playing style to generate accompanying bass and drums. Access millions of songs with auto-displayed chords, over 10,000 tones, and voice command functionality. It's designed to enhance your practice and performance experience.

Highlights
  • Auto chord display for millions of songs
  • Smart Jam with AI-generated bass and drums
  • Voice command control
  • BIAS tone engine with 10,000+ presets
  • Tempo control and looping for practice
  • Realistic virtual tube amps and effects
Features
Read full description

The smart amp and app that jam along with you using intelligent technology. Play and practice with millions of songs and access over 10,000 tones powered by our award-winning BIAS tone engine. *Auto Chords* Automatically display chords for millions of songs. Choose any song, and Spark will auto display its chords in real-time as you play. Easy controls let you slow down the song’s tempo or loop a difficult section as you master playing it. *Smart Jam* The Spark amp and app work together to learn your style and feel, and then generate authentic bass and drums to accompany you. It’s a smart virtual band that goes wherever you go! *Voice Command* The Spark app responds to your voice commands. Tell it to stream a rock song or a blues backing track, or ask for a virtual band to follow your playing. *Tone Engine* Whether you play pristine melodies, crunchy chords or soaring leads, Spark gives you a full amp modeling and multi-effects engine, powered by Positive Grid’s state-of-the-art BIAS with the most realistic virtual tube amps and effects on the planet. *Requires Spark Amp* *10,000+ Tones* The Spark app provides over 10,000 killer guitar and bass amp -and-FX presets from famous guitarists, professional session players, expert studio engineers and hit-making producers from around the world. If you have any questions or feedback, contact us via https://help.positivegrid.com/hc/en-us/requests/new

Screenshots

FFT4 screens
Spark4 screens

Verdict

The call

The clearest difference is price: Spark at Free against FFT's $10.99. Spark also leads on rating (4.8 vs 4.0) and update cadence (every 2 weeks vs every 6 months). FFT's advantage is review sentiment (86% vs 55%). On ads, in-app purchases, monetization model 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

Spark is free to download; FFT costs $10.99 up front. FFT sells 1 one-off in-app purchase and Spark sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Spark holds the better App Store score, 4.8 against 4.0. That said, the two scores are not equally well evidenced: Spark has 25K ratings behind it against 6, so its average is the more settled of the two. Written reviews complicate that: 86% of FFT's written reviews are positive against 55% of Spark's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

FFT ships an update every 6 months, Spark every 2 weeks. The most recent releases landed on October 14, 2026 and October 16, 2026 respectively.

Scorecard5 real differences · 5 level
FFT versus Spark: the parameters behind the verdict, then further details
ParameterFFTSpark
Price$10.99Free — better
Rating4.0 (6 ratings)4.8 (25K ratings) — better
Positive reviews86.1% of reviews — better54.9% of reviews
Number of ratings625K — better
Update frequencyEvery 6 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details — not scored
Size30 MB562 MB
Age rating+417+
DeveloperAndrew SmithPositive Grid Inc

Customer experience

FFT

All ratings6 ratings
Positive66.7%
Neutral0.0%
Negative33.3%
Written reviews36 reviews
Positive86.1%
Neutral2.8%
Negative11.1%

Spark

All ratings24,887 ratings
Positive97.4%
Neutral1.3%
Negative1.4%
Written reviews661 reviews
Positive54.9%
Neutral13.0%
Negative32.1%

Bugs and requests

FFT

Not enough reviews yet to summarise bugs or requests.

Spark

Reported bugs

5 issues
  • App frequently disconnects from amp
  • Tone selection issues and inconsistencies
  • Sudden loud noises or feedback from amp
  • Firmware update process is cumbersome
  • Spotify integration not working as advertised

Requested features

6 requests
  • Add looping functionality
  • Improve auto-chord detection and playback
  • Allow more customization of signal chain and effects
  • Integrate with more music services beyond Spotify
  • Add EQ controls for Bluetooth speaker mode
Show 1 more
  • Sync saved tones across devices

In-app purchases

1 purchases

FFT

One-time1
  • Reference Curve Files$9.99
1 purchases

Spark

One-time1
  • Experience Jimi Hendrix™$19.99

Questions

Is FFT free?
FFT costs $10.99, and also offers in-app purchases.
Is Spark free?
Spark is free to download, with in-app purchases available.
Which has better reviews, FFT or Spark?
Spark is rated higher. FFT averages 4.0 out of 5 from 6 ratings, while Spark averages 4.8 from 25K ratings.
Do FFT or Spark have ads?
Neither FFT nor Spark shows ads.
Which is updated more often, FFT or Spark?
FFT ships an update every 6 months, and Spark every 2 weeks. Most recently, FFT was updated on October 14, 2026 and Spark on October 16, 2026.

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