Comparison

Apollo Sound Injector vs MIDI Expression Control

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

Head to head
About

Apollo Sound Injector

Stream audio between iOS devices with this app and its companion. It supports Inter-App Audio for integrating synthesizers and sequencers, enabling complex audio processing chains. Designed for musicians, it aims to create a flexible, integrated music studio experience.

Highlights
  • Stream audio between iOS devices
  • Inter-App Audio support
  • Integrate synthesizers and sequencers
  • Build complex audio processing chains
  • Latency reduction algorithm
  • Desktop DAW integration
Features
Read full description

We're going to be focusing on development for Aleph Looper and Infinite Looper, and have decided to make this app free. Enjoy! -- Apollo Sound Injector makes it easy to stream audio from one iOS device to another. Use the app Sidecar with the device that is sending audio, and Sound Injector on the device that needs to receive the audio -- we have two separate apps so that it's easy to know which end is which. Both Sidecar and Sound Injector work with Inter-App Audio, so you can integrate iOS synthesizers and sequencers, and build complex audio processing chains. And if you're making music, you should also take a look at Apollo MIDI over Bluetooth -- the fast way to send MIDI between multiple devices. Secret Base Design has years of experience developing leading edge apps for serious musicians. Our "Apollo" series of apps are designed to let you use multiple iOS devices, as well as desktop and laptop computers, to build an integrated and flexible music studio. If you are using desktop DAWs, you can take advantage of Sound Injector on the desktop. ---- Note that with audio streaming over WiFi, there can be some latency, and performance will depend a great deal on your router, and the WiFi traffic. Sound Injector features a novel latency reduction algorithm -- but there are limits to how far this can go, and very low latency connections may also introduce audio glitches.

About

MIDI Expression Control

This application allows users to modify settings for MIDI Expression devices. Ensure your device has firmware version 2.6 or higher for iOS compatibility.

Highlights
  • Change device settings
  • Compatible with MIDI Expression devices
  • iOS firmware compatibility check
  • Free to download
Read full description

This is the Control Application for MIDI Expression devices. It lets you change settings for the devices. Please note that the iOS version of the Control Application is only compatible with devices running firmware version 2.6 and up.

Screenshots

Apollo Sound Injector2 screens
MIDI Expression Control4 screens

Verdict

The call

The clearest difference is rating: MIDI Expression Control at 5.0 against Apollo Sound Injector's 3.5. MIDI Expression Control also leads on review sentiment (100% vs 80%). Apollo Sound Injector's advantage is iOS requirement (7.0 vs 12.0). On price, ratings volume, update cadence and ads 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

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

MIDI Expression Control holds the better App Store score, 5.0 against 3.5. Both are backed by a comparable volume of ratings — 8 and 6 respectively. Written reviews point the same way: 80% of Apollo Sound Injector's written reviews are positive against 100% of MIDI Expression Control's.

UpkeepUpdate frequency

Apollo Sound Injector ships an update every 5 months, MIDI Expression Control every 6 months. Both last shipped on November 2, 2026.

Scorecard3 real differences · 7 level
Apollo Sound Injector versus MIDI Expression Control: the parameters behind the verdict, then further details
ParameterApollo Sound InjectorMIDI Expression Control
PriceFreeFree
Rating3.5 (8 ratings)5.0 (6 ratings) — better
Positive reviews80.0% of reviews100.0% of reviews — better
Number of ratings8 — better6
Update frequencyEvery 5 months — betterEvery 6 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS7.0 — better12.0
Further details — not scored
Size3 MB6 MB
Age rating4+4+
DeveloperPatrick MaddenRobert Jonkman

Customer experience

Apollo Sound Injector

All ratings8 ratings
Positive62.5%
Neutral0.0%
Negative37.5%
Written reviews5 reviews
Positive80.0%
Neutral0.0%
Negative20.0%

MIDI Expression Control

All ratings6 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Apollo Sound Injector

No in-app purchases

None

MIDI Expression Control

No in-app purchases

Questions

Is Apollo Sound Injector free?
Apollo Sound Injector is free to download, with no in-app purchases.
Is MIDI Expression Control free?
MIDI Expression Control is free to download, with no in-app purchases.
Which has better reviews, Apollo Sound Injector or MIDI Expression Control?
MIDI Expression Control is rated higher. Apollo Sound Injector averages 3.5 out of 5 from 8 ratings, while MIDI Expression Control averages 5.0 from 6 ratings.
Do Apollo Sound Injector or MIDI Expression Control have ads?
Neither Apollo Sound Injector nor MIDI Expression Control shows ads.
Which is updated more often, Apollo Sound Injector or MIDI Expression Control?
Apollo Sound Injector ships an update every 5 months, and MIDI Expression Control every 6 months. Most recently, Apollo Sound Injector was updated on November 2, 2026 and MIDI Expression Control on November 2, 2026.

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