SPL vs MF
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SPL
This professional-grade digital sound level meter measures decibels with advanced modes and filters meeting ANSI Type 1 standards. It allows storing, exporting, and calibrating measurements, and can be used with external calibrated microphones for precise results.
- Professional-grade digital sound level meter
- ANSI/IEC Type 1 standards compliant filters and modes
- Store, recall, and export GPS/time-stamped results
- Supports external calibrated microphones
- Adjustable calibration for accuracy
- Internal mic compensation filter
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SPL is a professional-grade digital sound level meter (decibel meter) for your iPad, iPhone or iPod touch. It includes all of the modes, filters, and features that you would expect from a professional ANSI or IEC Sound Level Meter. All filters and averaging modes meet or exceed the criteria for ANSI Type 1 standards or better. SPL is created from the same team who brought you the Audio Toolbox and ATB Plus. Store Results -- Uses the same powerful Save / Recall engine as our premier app, AudioTools. Allows storing GPS and time-stamped results, and exporting them to your computer. You can also use SPL with our calibrated iPhone measurement mic, iTestMic, or iAudioInterface. The screen flips if you turn the phone upside down, so that you can point the built-in iPhone mic directly at the sound source. *** Modes: Slow, Fast, Impulse, Peak, and Leq. *** Filters: A and C weighting, and 10 octave band filters. *** Includes a resettable Max field to track the highest reading. *** Includes a reference field (except in Leq mode) so that you can set a reference level and do seat-to-seat comparisons. The SPL meter can be fully calibrated. It comes preset with the calibration for a typical iPad, iPhone, and iPod Touch. Most iOS devices will be within a few dB of this reading. If you have access, even temporarily, to a calibrated sound level meter, just use the calibration field on the settings scree to match the meter, and you will be accurately calibrated. Also, see our other professional-grade audio apps: AudioTools, our premier suite of professional-caliber audio and acoustics test apps, Speaker Pop, to test speaker polarity, and RTA, a real-time analyzer for the iPhone. And, we have a group of calibrated, accurate measurement microphones, including iTestMic,iTestMic2, and iAudioInterface2, that allows full professional results for Type 1 or Type 2 measurements. This will allow measuring a range from approximately 30 dB SPL to 130 dB SPL. Each mic will include a calibration factor that you will enter into the SPL app for calibrated measurements. This mic will also work with Speaker Pop, our speaker polarity tester, FFT, RTA, ETC, and other acoustical measurement apps in our AudioTools app that is available now. Also, see our iAudioInterface2 system, which supports any pro test and measurement mic. Now includes an iPhone internal mic compensation filter, to cancel out the low-frequency roll-off present in the iPhone and other iOS devices. See our other audio apps, including AudioTools.
MF
This app recreates a classic analog effects pedal, offering a voltage-controlled oscillator with variable waveshape and envelope follower. It allows for processing and modulation of various audio inputs to create unique musical sounds.
- Voltage-controlled oscillator (VCO)
- Variable waveshape
- Hard sync and frequency modulation
- Envelope follower
- Modulate VCO frequency with input dynamics
- Mix VCO with audio input
- AUv3 effects plug-in
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The MF-107S Freqbox is a re-invention of Moog Music’s classic Moogerfooger MF-107S analog effects pedal. The MF-107 Freqbox, originally introduced in 2007, contained several complete modular synth functions: a voltage-controlled oscillator (VCO) with variable waveshape capable of being hard synced and frequency modulated by the audio input, and an envelope follower which allowed the dynamics of the input signal to modulate the frequency of the VCO. In addition, the amplitude of the VCO was controlled by the dynamics of the input signal, and the VCO could be mixed with the audio input. A direct descendant of the original Moog modular synthesizers, the MF-107 was adapted to process, modulate, and play with inputs ranging from guitar, voice, and synthesizer to any imaginable audio source. The MF-107 Freqbox has been meticulously recreated as the MF-107S, capturing not only the jagged, freaky sounds of the original, but also the organic way in which the parameters interact to create a musical playing experience. The MF-107S is an AUv3 effects plug-in that requires a compatible host or DAW to function.
Screenshots
Verdict
The clearest difference is rating: MF at 4.4 against SPL's 3.0. MF also leads on update cadence (monthly vs every 6 months) and iOS requirement (11.0 vs 15.0). SPL's advantage is price ($8.99 vs $14.99) and review sentiment (68% vs 50%). On ratings volume, ads, in-app purchases and monetization model 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
SPL costs $8.99 and MF $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
MF holds the better App Store score, 4.4 against 3.0. Both are backed by a comparable volume of ratings — 4 and 7 respectively. Written reviews complicate that: 68% of SPL's written reviews are positive against 50% of MF's, so the app with the better star average is not the one people write more warmly about.
SPL ships an update every 6 months, MF monthly. The most recent releases landed on October 23, 2026 and October 16, 2026 respectively.
| Parameter | SPL | MF |
|---|---|---|
| Price | $8.99 — better | $14.99 |
| Rating | 3.0 (4 ratings) | 4.4 (7 ratings) — better |
| Positive reviews | 67.6% of reviews — better | 50.0% of reviews |
| Number of ratings | 4 | 7 — better |
| Update frequency | Every 6 months | Monthly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 30 MB | 41 MB |
| Age rating | 4+ | 4+ |
| Developer | Andrew Smith | Moog Music Inc. |
Customer experience
SPL
MF
In-app purchases
SPL
No in-app purchases
MF
No in-app purchases









