Organ Manuals

Opus #1

The First Church Organ
On Android.

A Church Organ App

Have you ever played a church organ on Android? Based on high-quality recordings of a complete real French church organ?

With Opus #1 you can do that.

The original organ

Just like the Real Organ

The Stiehr-Mockers organ was built in 1843 for the Protestant Church in Romanswiller, Région de Wasselone, France, by the famous organ builders Stiehr and Mockers from Alsace.

Opus #1 Ultimate includes all 21 organ stops, 2 manuals plus pedal and a key range of 4½ octaves – just like the real organ.

Feels like a Real Organ

We also took care to make it feel like the real organ, with great realistic sound, full midi support via USB so you can play it using a midi keyboard or a midified organ console and lowest latency (time between pressing a key and the start of the sound) possible on your device.

For best latency, we recommend a Galaxy Nexus.
See our FAQ on Latency for more details.

The original organ console

Played by Markus Sigg –

Great Sound

Opus #1 comes with high quality samples for all contained stops (different pipe sounds). The recording session was done by Joseph Basquin from Jeux d’orgues ( Of course, all stops can be combined and used like on the real organ.

Listen to more sound samples

Fit for Organ Consoles

Opus #1 Ultimate contains everything needed for a midified organ console:

  • ✓ 21 organ stops
  • ✓ 2 manuals plus pedal
  • ✓ Registration view
  • ✓ Midi via USB
  • ✓ Lowest possible latency

Galaxy Nexus and Midi Keyboard

Midi via USB

Opus #1 Ultimate supports Midi In/Out. You can play Opus #1 from your midi keyboard or play an external midi device from Opus #1.

For requirements and a list of Android devices known to work, see our FAQ.

Midi File Player

We also included a midi player into Opus #1 Ultimate that plays standard midi files either on the app itself or via Midi/USB on your connected midi equipment.

App Versions

Opus #1 comes in different versions:

Opus #1 Ultimate
The complete Stiehr-Mockers organ. This includes all 21 organ stops of the Stiehr-Mockers organ, 2 manuals + pedal and a keyboard range of 4 1/2 octaves – just like the original organ. Opus #1 Ultimate then adds 5 predefined combinations and 2 additional couplers (I/II, II/P).

Opus #1 Free
A small version the organ with 1 manual, no pedal, 9 stops, 4 combinations, no midi support, ad-supported.

If you want to play this organ on an iPad or iPhone, there are iOS versions available from Markus Sigg at


Disposition of Opus #1 Ultimate
54 notes,
4 ½ octaves
Positif de dos,
54 notes,
4 ½ octaves
27 notes,
Bordun 16′ Bordun 8′ Subbass 16′
Montre 8′ Prestant 4′ Floete 8′
Bordun 8′ Nazard 2′2/3 Prestant 4′
Salicional 8′ Doublette 2′ Trompete 8′
Octav 4′ Tierce 1′3/5 I/P, II/P
Floete 4′ Cymbale 3 rgs (1/2′)
Doublette 2′ Hautbois 8′
Cornett 5 rgs I/II
Fourniture 3 rgs (1′)
Trompete 8′

Disposition of Opus #1 Free
54 notes,
4 ½ octaves
Bordun 16′
Montre 8′
Bordun 8′
Octav 4′
Floete 4′
Doublette 2′
Cornett 5 rgs
Fourniture 3 rgs (1′)
Trompete 8′


Grand Plein Jeu
combinations with a „principal tone“. Many people think about this sound as the „typical“ church organ sound. The Ultimate version comes with 2 Grand Plein Jeu combinations.
Grand Jeu
a combination of reed stops
the „full organ“
a combination of „flute“ stops
Screenshot Opus #1 Pro Combinations

Technical Details


Up to 512 pipes can sound simultaneously depending on the processing power of your Android device.

Low Latency Audio

Low latency audio is a weak spot of Android (see Opus #1 supports the lowest latency possible on your Android device.


Opus #1 supports multi-touch i.e. you can press multiple keys at the same moment. The number of simultaneously pressed keys is only limited by your Android device.

Hardware Requirements

✓ Runs on android >= 4.0.3, phones and tablets
✓ Android support for USB-Host/-OTG and thus Midi/USB requires Android >= 3.1. Not all devices with Android >= 3.1 support USB-Host/-OTG. You can use the trial version to test your device. It’s not necessary to root your device.
✓ Opus #1 Ultimate supports all class compliant USB-Midi devices and interfaces. Typically, USB-Midi devices that don’t need drivers for Windows or MacOS are class compliant.
✓ Opus #1 Ultimate needs ca. 21.1 MB (typically on your sdcard) for the organ samples and midi files and Opus #1 Free needs ca. 9.5 MB.
✓ For the best sound, the device should have at least a 1GHz single core processor
✓ Use headphones / external speakers for better sound; phones speakers are not made for organs

Requested Permissions

Opus #1 Ultimate requires the following permissions:
android.permission.WRITE_EXTERNAL_STORAGE to extract the sound samples onto the sdcard
android.permission.VIBRATE for vibrate on touch support
android.permission.MODIFY_AUDIO_SETTINGS for better audio support (OpenSL)
android.permission.INTERNET to be able to download midi files if selected e.g. in a browser to enable mail apps to forward midi file attaments to this app to check the license

Opus #1 Free requires the following permissions:
android.permission.WRITE_EXTERNAL_STORAGE to extract the sound samples onto the sdcard
android.permission.VIBRATE for vibrate on touch support
android.permission.MODIFY_AUDIO_SETTINGS for better audio support (OpenSL)
android.permission.INTERNET and android.permission.ACCESS_NETWORK_STATE to load ads

Frequently Asked Questions

Questions regarding all Apps

I purchased one of your apps but now it claims it’s not licenced and asks me to buy it again. What can I do?

The pro and ultimate versions of my apps check the license. If they can not confirm the license (e.g. if they cannot reach the servers) until three days after installation, they display a reminder to buy it. After about a week, they refuse to work.

To check the license, they first try to determine if they were installed via the Google Play Store app. If they can confirm it, they do not perform any other check. Otherwise, they trigger a license validation request to the Google Servers and to Of course, an internet connection is needed for this and it takes some time.

So, what to do? Please make sure you have an internet connection, then start the app (this should trigger a server request) and wait some time for the servers answer (1 minute should be enough). If you then close the app and restart it, it should not complain anymore.

If the license has been confirmed once, no server request is triggered anymore until the app is deinstalled and reinstalled.

If you purchased the via on the Google Play Store, the same account that you used for the purchase has to be setup on your android device.

If you purchased it via AndroidPit, the AndroidPit AppCenter has to be installed and the account you used for the purchase has to be set up in the AppCenter.

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Questions regarding Opus #1

Due to the latency problem (see the FAQ on Latency), the only devices I can recommend at the moment are the Galaxy Nexus as phone and the Nexus 7 (2012) if you want a tablet. Both support Midi/USB. The Nexus 7 (2012) is slightly worse than the Galaxy Nexus.

First tests show that the latency of the Nexus 7 (2013) is roughly comparable to the Nexus 7 (2012) [Read More].

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What are the requirements for Midi/USB?

There are two requirements
1) The Android device has to support USB-Host or USB-OTG. You need at least Android 3.1 for this. In addition, the hardware and Android adaption of your android device has to support USB-Host/-OTG. Many devices need a special USB-OTG adapter that’s either connected to the Micro-USB port or to a proprietary port.

2) The USB-Midi device (your keyboard, organ console, USB-Midi interface etc.) has to be standard-compliant. Most current devices are standard-compliant. An indicator (but no proof) is, if you don’t need a driver to make it work with your PC/Mac (though the manufacturers often provide additional drivers even for standard-compliant devices).

If you are not sure, just test it using the trial version from

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Is root needed for Midi/USB?

No, Midi/USB works without rooting.

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Does Midi/USB work for my hardware?

At the time of this writing, the Google Developer Console tells me there are over 2800 different android devices/configurations for which my apps can be downloaded. It’s impossible to test them all.

So please, look at the other FAQs, to see if your devices are listed. If you are not sure, just test it using the trial version from If it works and the devices are not listed, please tell me.

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How can I connect a Midi keyboard?

The typical setup is:

Android device <–> USB-OTG adapter <-> Midi keyboard with USB connector

If your Android device has an USB-Host connector (e.g. Acer A500), no OTG adapter is needed.

For midi devices with din connector, use a Midi-USB interface.

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My setup does not work. How can I check it?

Hardware Level

1) You may connect an USB mouse to the OTG adapter or the USB-Host port. A mouse pointer should appear on the screen that you can move with the USB mouse. If so, USB-Host/-OTG works at the hardware level. It may still not work due to software problems.

2) Make sure the keyboard/interface is powered. Android devices that support USB-Host/-OTG can provide power via USB.

3) If your USB-Midi interface has an indicator led, that led typically should flicker when keys are pressed on the keyboard or when midi data is send from the app.

Software Level

1) Check if Android sees the device using e.g. the free app “USB Device Data” (

2) Check the devices class and subclass displayed e.g. in the free app “USB Device Data” ( Standard-compliant devices have class 1 (i.e. audio) and subclass 3 (i.e. Midi streaming).

3) If you connect your midi device and the app is installed, Android should display either a dialog asking for permission to access the device or a dialog asking which app to start.

4) You can use the free app “USB Midi Monitor” ( to see if you can receive midi events.

5) If “USB Midi Monitor” displays midi events, but my apps don’t react, check the apps settings. You may e.g. set a keyboard to omni mode (i.e. receive on all channels). Please be aware that my apps count midi channels starting with 0 till 15. Many keyboards use 1-16; i.e. the numbers may have to be one off. By default, the apps are configured such that at least one manual should react, no matter which channel the midi keyboard uses.

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How can I connect multiple manuals? With a Midi merger or a powered USB hub?

Both ways, using a Midi merger or a USB hub basically work.

If you use a USB hub, use a powered one. The Android device probably does not provide enough power for the hub and the devices. Also, be aware that Android support for USB hubs seems to be unstable. E.g. sometimes, Android thinks devices are still connected that are no longer connected via a hub.

Using a Midi merger certainly is the more stable solution, though it’s the more expensive solution too.

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How to establish a Midi connection between the Android device and a PC/Mac via USB?

That’s only possible by using a workaround. The problem is that the smartphone/tablet acts as a „USB master“ like the PC itself if used for Midi/USB. It cannot act as a „USB device“. Since there can only be one master in a USB connection, a direct connection does not work.

The workaround is basically the same you have to use when you want to setup a midi connection via USB between two PCs/Macs: You have to use 2 USB-Midi interfaces, one on the PC/Mac and one on the smartphone/tablet and connect them via Midi din cables.

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Which Android devices (don’t) work with Midi/USB?

This list is not comprehensive and I cannot guarantee the correctness of customer reports.

If you are not sure, just test it using the trial version from If it works and the devices are not listed, please tell me.

All my music apps have been tested successfully on:
– Galaxy Nexus
– Nexus 7 (2012)
– Acer A500

Reported to work by customers (no guarantee):
– Asus TF101
– Samsung Galaxy Tab S2
– Some Samsung Galaxy S2 devices (on some S2’s the installed android version seems to have a bogus USB-Host implementation)
– Samsung Galaxy S3
– Motorola Xoom 2
– Samsung Galaxy Tab 2 7.0 (GT-P3113/Android 4.2.2)
– Samsung Galaxy Tab 2 10.1 (with Samsung otg dongle)
– Samsung Galaxy Tab 3 (the Tab 3 7.0 seems not to support otg? Must be one of the larger versions?)
– Samsung Galaxy Note 1
– Samsung Galaxy Note 8
– Medion LIFETAB_S1033X (Android 4.4.2)

Reported not to work by customers:

– Nexus 4 (USB-OTG has been deactivated by Google; may work with a custom rom and an OTG adapter with external power)
– Acer Iconia A110 (no USB-Host/OTG)
– Kindle Fire (no USB-Host/OTG)
– Kindle Fire HD (no USB-Host/OTG)

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Which USB-OTG adapters work with Midi/USB?

Which USB-OTG adapter you need depends on your Android device.

Some devices (e.g. the Acer A500) have a USB-Host port. For them, no adapter is needed.

If the Android device only has a micro USB port, the Samsung USB-OTG adapter ET-R205UBEGSTD usually works (see This adapter works for me on the Galaxy Nexus and the Nexus 7.

Other adapters like e.g. this one should work for micro USB ports too.

Some devices need a custom adapter, e.g. the Samsung Galaxy Tab. An online search or a search in device specific forums may help to find the correct adapter.

If you are not sure, just test it using the trial version from If it works and the devices are not listed, please tell me.

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Which USB Midi keyboards (don’t) work with Midi/USB?

This list only mentions keyboards that contain a USB port. For Keyboards with Midi din connectors only, you need a USB-Midi interface. The list is not comprehensive and I cannot guarantee the correctness of customer reports.

All my music apps have been tested successfully with:
– M-Audio KeyStudio 49
– Akai LPK25

Reported to work by customers (no guarantee):
– Alesis Q49 Keyboard Controller
– ESI KeyControl 49 XT
– M-Audio KeyStation 61
– M-Audio Axiom Air Mini 32 (caution with htc one: works as usb audio out, the htc one reroutes audio)
– M-Audio KeyStation Mini 32
– M-Audio Oxygen 61
– M-Audio Oxygen 25
– Evolution MK-361

Reported not to work by customers:
– Roland PC-300?

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Which USB Midi interfaces (don’t) work with Midi/USB?

This list is not comprehensive and I cannot guarantee the correctness of customer reports.

All my music apps have been tested successfully with:
– Roland/Edirol UM-1EX (deactivate “advanced driver” switch)
– E-MU Xmidi 2×2

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Why is the latency (time between pressing a key and the start of the sound) so high?

First, when we talk about latency here, we mean the complete „key to sound latency“, i.e. the time between pressing a key and the start of the sound. It’s important to distinguish this from the pure audio output latency, which is the time between handing over audio data to Android until the sound can be heard. If you see a one digit latency number, that’s typically either pure output latency or the size of some audio buffers. Good „key to sound latency“ for virtual instruments starts below 50ms. According to, the „key to sound latency“ of a real piano from touching a key until the string vibrates is about 20 to 30 ms (staccato forte case) due to the mechanics involved.

Up until Android JellyBean/4.1, Android itself had a serious latency problem (see Actually, it was a problem with pure audio output latency and with process priorities/scheduling. Since JellyBean, Android can support low latency – if the app developer and the hardware manufacturer have done their homework. For my music apps, I did. They all support the low latency features of JellyBean and later. However, most android device manufacturers did not. This article might be of interest in this context: Why Mobile Low-Latency is Hard, Explained by Google as well as this video: Google I/O 2013 – High Performance Audio.

So how can you reduce the audio latency? Besides using Midi over USB (that’s actually faster than using the touch-screen), the best answer is to use an Android device that supports low latency.

The best low latency Android device I know of is the Galaxy Nexus. It’s outdated, but none of the more recent devices matches its latency of about 60ms.

The Nexus 7 (2012) is on a second tier, reaching about 90-110ms. As far as I know, the Nexus 4, the Nexus 10 and the Sony Xperia Z/ZL should be in this tier too, but that’s hearsay. Please, be aware that the Nexus 4 has a problem with USB-Host/OTG.

First tests show that the latency of the Nexus 7 (2013) is roughly comparable to the Nexus 7 (2012) [Read More].

As far as I know, most other devices have worse latency, often in the range of 150-300ms.

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Why does the Nexus 7 (2012) not recognize all 10 touch points? Why do the keys pressed on-screen jump over?

The Nexus 7 (2012) seems to have a problem with grounding. If you hold it in a hand, this problem occurs. If you put the Nexus 7 (2012) on a table or ground it by connecting it to a power supply, the problem does not occur and the Nexus 7 (2012) supports up to 10 simultaneous touch points.

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Midi/USB seems to work (the on-screen keys react when I press a key on my keyboard), but I cannot hear anything?

If you tried to increase the volume without success, it may be an audio reroute feature of your android device.

Some current devices (customers reported this problem for the HTC One and the Sony XPeria SP/iRig keys) try to recognize USB audio output devices (e.g. USB speakers). If they recognize such a device, they reroute audio output to usb.

Now, some midi keyboards offer USB audio features (e.g. an audio control interface) that can trigger that reroute feature. If you don’t find a setting (e.g. in the android settings app) to prevent rerouting, you may try the app „Sound About“ ( According to customer reports, it seems to work for both the HTC One, the Sony XPeria SP and the Sony Xperia Z1.

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Why does the sound stutter on my Galaxy S3?

Go to the settings app -> peripherals -> sound -> system and deactivate „auto haptic“ described as „Set the device to vibrate when playing sounds in downloaded applications“

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Free Ultimate
Purpose Small organ, mobile only Full organ, with Midi
Manuals 1 manual, 4 ½ octaves 2 manuals, 4 ½ octaves
Pedal No Yes
Stops 9 stops 21 stops
Combinations 4 combinations 5 combinations
Polyphony Up to 512 pipes simultaneously Up to 512 pipes simultaneously
Low Latency Support Yes Yes
Midi via USB No Yes
Midi Player No Yes
Ad Supported Yes No
Price Free 24,99€
plus VAT where applicable
Opus #1 Free on Google Play Opus #1 Ultimate on Google Play
Or test the full organ with a 7 day free trial