Stereo Modulator vs SL Tune
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stereo Modulator
This audio effect plugin transforms mono sound into stereo, adding width and depth. It uses micro-delays to create a natural sense of space, with optional LFO modulation for a Leslie speaker-like effect without pitch shifting. Ideal for creating separation in mixes, especially for guitars and vocals.
- Mono to stereo conversion
- Adjustable stereo width
- Optional LFO modulation
- Micro-delay de-correlators
- Creates natural spatial depth
- No pitch shifting or echo
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Stereo Modulator is an AU3 effect that converts mono sound into stereo, with an adjustable width and optional LFO modulation. It works by using a bank of randomized stereo de-correlators that apply micro-delays to introduce random differences between the spectrums of the left and right audio channels. In its output we hear a natural sense of space that is not present in mono recordings. It's similar to the sound space one gets from using a stereo reverb plugin except that it is tight and clear, without echo. It can operate either as a static effect or it can be gently modulated by a low-frequency oscillator. The modulation is akin to the sound of a Leslie speaker, except that it doesn't do any pitch shifting, so the output remains focused and tuning is not compromised. This effect is especially useful for mixing overdriven electric guitar sounds together with vocals. Using Stereo Modulator on the guitars, we can push them out to the sides, creating a space in the centre for the vocal to cut through, without needing to reduce the volume of the guitars. NOTE: Stereo Modulator is an AU3 plugin only, not a standalone app. To use it, you will need an audio unit host app such as Garageband or Audiobus.
SL Tune
This app offers vocal pitch and tone effects for iPad, providing quick corrective or creative processing. It features fast pitch correction, modern vocal tone shaping, and mix control for flexible audio manipulation. It supports AUv3 for integration with compatible music hosts.
- Fast pitch correction
- Modern vocal tone shaping
- Mix control
- Factory and user presets
- AUv3 support
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SL Tune is a vocal pitch-correction and tone effect for iPhone and iPad. Insert it on a vocal track in a compatible AUv3 host. Choose a key and scale, or select the allowed notes yourself. Natural mode preserves small pitch movements, Hard gives faster correction, and Robot locks pitch to the selected root across octaves. Six controls shape the sound: Retune, Humanize, Formant, Snap, Echo and Mix. Formant changes the tonal balance. Mix blends processed and original audio. Start with one of six factory presets: Classic Hard, Trap Lock, Silk Vocal, Clean Fix, Robot Grid and Echo Adlib. Save and load your own presets locally. The resizable interface adapts to portrait, landscape and compact host windows. Use SL Tune as an AUv3 effect in a compatible music host, or open the standalone app to preview and adjust the controls. Pitch correction works best on a single vocal line. It is not designed to tune a complete mix or separate voices from background music.
Screenshots
Verdict
The clearest difference is update cadence: SL Tune at every 9 days against Stereo Modulator's every 3 months. Stereo Modulator's advantage is price ($2.99 vs $7.99) and ratings volume (3 vs 1). On rating, review sentiment, ads and in-app purchases 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
Stereo Modulator costs $2.99 and SL Tune $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Stereo Modulator against 5.0 for SL Tune. Both are backed by a comparable volume of ratings — 3 and 1 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
Stereo Modulator ships an update every 3 months, SL Tune every 9 days. Both last shipped on October 24, 2026.
| Parameter | Stereo Modulator | SL Tune |
|---|---|---|
| Price | $2.99 — better | $7.99 |
| Rating | 5.0 (3 ratings) | 5.0 (1 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 3 — better | 1 |
| Update frequency | Every 3 months | Every 9 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 10.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 2 MB | 37 MB |
| Age rating | 4+ | 4+ |
| Developer | Blue Mangoo Consulting Company Limited | VIACHESLAV ZHILTSOV |
Customer experience
Stereo Modulator
SL Tune
In-app purchases
Stereo Modulator
No in-app purchases
SL Tune
No in-app purchases









