One of the unsung apps that exists out there and it got updated recently again with ​Multitouch support and Sidechain compression. Did not mention the last update that also made it possible to control it with midi. Unfortunately not to play notes with it but it is great for direct manipulation and it is possible to control it with for example G/Stomper, This I have not tried yet and do not know how that works tough. 
In either case this is one cool and multi faceted sample instrument with a shitload of effects and possibilities. Plus being able to record/load into four different channels (but pushing it fully a powerful device is needed).
Have written about this some times now but if you never saw thesse posts think it is always good to bring it up again...

Google Play:
​play.google.com/store/apps/details?id=me.rocks.grainstorm

Use as/for:
- Sound design
- Experimental musical instrument
- Fun
- An alternative to pre-recorded music.

Key Features: 
- Four tracks
- Full control over the source sound
- Infinite options to shape the grain. 
- LFOs and Envelope Followers
- Handmade effects
- Realtime Crossynthesis 
- Time Stretching, Phase Vocoding
- Supports sound files of up to seven minutes length in any audio format 

First use instructions: 
1. Press POWER. Upper right power button turns on audio engine which is TURNED OFF on startup to save battery.
2. Press EJECT. Load a sound file. 
3. Press PLAY. 

Further instructions in the menu.

Recommended device specifications:
- 64bit CPU
- 2GB+ RAM
- Android 8.1+
Not recommended for low end devices.

These videos show some interesting ideas for using Specdrums and soon there I should be able to test them myself and will write a review as soon as possible and how and which apps  they will work good with on Android. Think it is a brilliant idea and have fantasized some time now to paint some walls to use for playing music....

This had a small journey that have been going on for around two years since first being announced on Kickstarter to later being bought up by a toy company doing robotic starwars toys and other things.
So now it is here and have been fascinated by this since seeing it at first.
Basically it is rings that can easily learn to read colours that can be used to trigger sounds on a device through bluetooth.
It seems to work good and hopefully will get some extra monies to buy a pair and try them out.
Was hoping that the price would be lower. My treshold being set to around fifty up to 60... for two of them as one would seem a little bit too limited.
Now they are about 65 monies for one and 100 for two.
They do look like a lot of fun though and would be great for playing live as it can use colours on anything, like clothes or paintings etc.
To see a whole band perform tapping walls would look wonderful!
To have a couple of these for a theatre would seem like a must...

Here is a short list of what can be done:

• Tap any color or the included Play Pad to create sounds, loops, and beats.
• Discover music creation without spending money on expensive, singular instruments
• Scalable for all skills levels, from curious-minded kids to seasoned musicians
• Connects via Bluetooth Low Energy as a Bluetooth MIDI device
• Long battery life of 2+ hours per charge
• Specdrums MIX app with curated sound packs
• Specdrums Music app with instruments, drum kits, and other sound pack

What is worth is important to mention as well is that it can be used to trigger other software that allows for Bluetooth midi. 
​It will be fun to see what people will do with this.

​Also hope to see them used on Android with some different devices to see how they perform.

To read more or see more videos go here:
www.sphero.com/specdrums

Read some time ago that Burial made his first classic albums using Soundforge without using quantification and placing loops and sound by ear. When he finally did release music sequenced something got lost...
So here is a chance to get your inner Burial going!
As this app use samples (that can be recorded as well) and you place them by sight and ear only.
It is for free and no ads!!!
Plus that it looks great.

Googe Play:
play.google.com/store/apps/details?id=com.stianremvik.bitwaves2

Record with mic, play in polyphony, compose without grid and bounce to wav in this experimental and very easy to use music creation tool.

BIT20 Ensemble, founded in Bergen, Norway in 1989 promotes the performance and presentation of new music through concerts, new music events and hands-on-projects in composition. Read more at www.bit20.no.

BITWaves2 is primarily made as a tool for use in BIT20’s outreach composition program. Development is supported by BEK, Bergen Center for Electronic Arts.

Idea: Ole André Farstad
Design and programming: Stian Remvik

Robin a collaborator of Musical Android wrote this about a very useful tool for many apps with samplers that can load SFZ on Android and well worth learning if wanting to create your own deep sample instruments...

Folder-to-SFZ Convertor, made by the excellent Versilian Studios, is a free application which allows you to very easily make your own SFZ instruments from your own samples. Given that the SFZ format seems to be the one favoured by Android developers, it is an application that Android music makers should definitely be aware of.
 
It might seem a bit daunting at first, but once you get the idea it is actually extremely easy to use. Just take the time to watch the really helpful video guides on the Versilian Studios website and you'll be up and running. It's really just down to naming your samples correctly. There is also a downloadable user manual on their website.
 
For such an apparently simple application it actually allows you great control. You can set the attack and release for samples, include different velocity layers and even round-robin samples (multiple samples of the same note, with their minor fluctuations, to be played in order or randomly when that note is triggered, giving the instrument a more realistic feel).
It's the easiest way I've found to create a SFZ instrument with all of that functionality.
 
Folder-to-SFZ Convertor is platform agnostic but requires Java to run. I've tried running it through some Java emulators for Android without any success - if anyone manages it please leave a comment - so you'll need to use it on a desktop or laptop.
 
One really important thing to note though: it was pointed out on a forum by internet user peastman that the SFZ file produced by Folder-to-SFZ Convertor has an error which prevents it working properly on Android (and Mac apparently). It is really easy to fix though. All you need to do is open the SFZ file as a text file and delete a backslash (\) symbol before saving it again without it. Here's an example. At the top of the SFZ text file, well one line down, it will say
 
default_path=\Example Samples\

when it should be

default_path=Example Samples\
 
(…obviously ‘Example Samples’ here is used for the purpose of this example only - yours will have the name of the folder that contains your samples instead).
 
The last time I used Folder-to-SFZ Convertor, this error in the resulting SFZ file was still there so please be aware of it - it's so easy to fix though so it's really not a problem.
 
Folder-to-SFZ Convertor can be found on the Versilian Studios website here
 
http://vis.versilstudios.net/sfzconverter.html

This can be fun for getting some unpredictable but good ideas going...
Got a serious Beatles Number nine vibe to some of the things.

The video by Soundtestroom are using the iOS version so some of the things shown are not of importance for the Android version.

Google Play:
play.google.com/store/apps/details?id=cc.openframeworks.ofxFluxlyAndroid

Fluxly is a new type of sonic game, a musical physics looper.

Fluxly is a musical electronic sampling synthesizer where you create new instrument scenes by moving and spinning colorful Fluxum sound sample players. A built-in 2D physics engine brings a whole new approach to knob twiddling and sound making. 

You can choose from a bank of built-in sound samples, or record your own samples and play them back in either direction at any speed. By touching two Fluxum and pushing them together you can link them into looping gear train machines. You can also enable movement and let the physics engine take over as the Fluxum bounce around the instrument for random sonic fun.

Recording can be done right in the app, and sample loops can be up to about 10 seconds long. You can also customize all of the sounds in Bank 1 by using filesharing features of your phone or tabley to upload any sound samples from your computer.

Fluxly was created by artist Shawn Wallace, who is also part of the Fluxama art collective that has created the apps Noisemusick and DR-OM. Fluxly is open source software and was built using openFrameworks, Box2d, libPd and Pure Data. See more at fluxly.com.

Google Play:
play.google.com/store/apps/details?id=com.teotigraphix.drumpadbeats.demo

Drum Pad Beats is a fun beat/composer - scene/remixer to capture those ideas when that flash of inspiration hits while away from the studio.

Drum Pad Beats is aimed at users that want to create rhythms and melodies using pads and step sequencers. With the added ability to export their creations to wav, ogg or midi loops (zip, pcmsynth for Caustic), user ideas can be taken farther in mobile or desktop Digital Audio Workstations.

Great for sharing beats/tracks as dpb files and remixing another artist's track, the track could then be remixed again adding even more flavor. Drum Pad Beat's project file contains everything another user needs to take that idea even farther.

Drum Pad Beats Discord - https://discordapp.com/invite/DS9J3cy (Drop in and say Hi)

New to Drum Pad Beats? Check out the friendly, In App Help UI and Quick Start Guide: https://www.teotigraphix.com/help/drum-pad-beats/index.html

HELP VIDEOS

https://www.youtube.com/watch?v=KnyZaJjWFOw&list=PLfafVvhM8YrfbSWV_w8I8S4Vi17JeL2h8&index=1

FEATURES

+ Adjustable U/I scaling (Settings)
+ Portrait or Tablet layouts
+ In App Help UI with documentation tips
+ 16 Drum pads, 12 Synth pads
+ Dual pad layout for Drum and Synth pads on one screen (remixing/recording live)
+ 63 Scene containers for programed Pad loops w/ 1 2 4 8 measures
+ Song sequencer with 16 playable/exportable sections.
+ Sampler and Chord Arpeggiator, diatonic chord interval arpeggios
+ Keyboard layouts for synth or sampler, 64, 36, 16 pad variations
+ Custom Scale and Key globally or per Scene
+ Record real-time remixes from pad looping and Scene changes as wav, ogg, midi
+ Record overdub for note entry (touch latency varies per device)
+ Metronome timing
+ Full Mixer and Effect for all Drum/Synth pads
+ Drum pad choke groups (4 groups per 8 pads)
+ Audition Browser to load/hot-swap new Drum/Synth kit sounds
+ Expandable Sound Library with Sound expansion packs available on Google Play.
+ Factory Sound Kits (808, 909, Metatronics, various others)

NEW/LOAD/SAVE/EXPORT

+ Create New Project
+ Load Recent/Project
+ Save Project As...
+ Export .pcmsynth preset with MIDI for the Caustic App
+ Export (each Scene/Section as a separate) .wav, .ogg, .mid to your favorite DAW or midi editor
+ Export Song MIDI as one file containing individual channels for each pad 
+ Export Scenes as wav loops zip archived

STEP SEQUENCER

+ Custom Scene color/name
+ Pad loop trigger for remixing live.
+ 63 unique pattern scenes with 1, 2, 4 and 8 measures
+ Pattern 1/16 & 1/8 Swing

PATTERN EDITING

+ Drag n Drop Pad or Scene to Move or Duplicate note data.
+ Clear all Scene data, per pad bank note data or per pad note data
+ Duplicate note data when expanding measure length
+ Arpeggiator note generation with Samplers and Synths (allows for happy accidents)

Plus a lot more... Check out the videos and help documentation

NOTE - The Demo is a fully functional app with the non-activated Full features listed below;

App Menu commands not activated

- Load Recent Project
- Load Project
- Save Project As...
- Export As.. (wav/ogg/mid)

Functionality

- Arpeggiator generator.
- Real-time MIDI/Audio record/remix wav/mid/ogg..
- Scene Export (wav/ogg/mid).
- Section Export (wav/ogg/mid).
- Song Export (wav/ogg/mid).

It´s Modular!

Always get excited when things are modular.

This is a new concept as it does not use a tradtional sequencer but reads the modules loaded with a sample/synthesizer in the order they are in the chain. 
So think that it can lead to happy accidents and to think a little bit more non-linear.
It is as is a little bit basic with not too much choice in modules but it looks like it can be expanded in all kinds of directions depending on the will of the creator.

It also records sound, making it a fun thing to use for enviromental sound collages.

It is for free and does not come with adverts.

Cool with a small new modular addition to the Android universe and if expanded futurewise can be something mighty interesting...

Google Play:
play.google.com/store/apps/details?id=com.jf.pocketcomposer

This music composition app lets you record sounds anytime and anywhere with your phone. You can arrange them in a graph-based scoring layout to create intriguing compositions.

Instead of starting with a cluttered interface narrowing your inspiration at the moment you open the app, the Pocket Composer starts with a blank white canvas, ready for your imagination.

Features:

- 16 track polyphony
- record sounds
- import .wav from SD-card
- synthesizer module
- audio fx: ringmodulator, delay, filters
- save and export to SD-card, share via e-mail, bluetooth, google drive, ...

With more than 1,200 samples, 50 editable programs, 80 editable sequences and iconic MPC workflow, iMPC is the first app to bring all the functionality of a classic Akai Professional MPC to a Samsung Galaxy Android Device. iMPC for Android includes everything needed to create beats quickly and easily, including built-in effects, with the ability to create new sequences and record and overdub beats. Time correction from 1/8 note to 1/32T with variable swing, and Note Repeat from 1/8 note to 1/32T with latch control are also built in. The app’s built-in sampler can record samples three different ways: 1) the mic on the Samsung device; 2) the line input; 3) the multi-touch turntable interface in iMPC to record samples directly from other music libraries.

Features:

• More than 1,200 samples, 50 editable programs, and 80 editable sequences
• Exclusive iMPC sound set and classic Akai Professional sound library
• Sample from Android mic, line in or music library using multi-touch turntable interface
• 16 Levels mode: 16 levels of attack, velocity, length, and tuning
• Note Variation slider: adjust attack, velocity, length, and tuning as you play
• Trim and categorize samples, undo takes and erase samples
• Built-in effects: delay, bit crusher, master compressor/limiter
• Export your projects for use in the desktop MPC Software or in wav format

Akai Professional iMPC, is now also available from the Samsung Galaxy Apps Store.
iMPC for Android was created in collaboration with app developer Retronyms, and the app fuses the workflow of an Akai Professional MPC (Music Production Center) with tools for composing, editing and mixing music on the user’s Samsung device.

iMPC for Android at launch will be available exclusively to Samsung phone and tablet users as an in-app purchase inside Samsung’s Soundcamp, a digital audio workstation. The Soundcamp DAW enables users to record, edit and mix up to 8 audio/MIDI tracks, and also has a piano roll editor for music editing.
iMPC for Android Features:

• More than 1,200 samples, 50 editable programs, and 80 editable sequences
• Exclusive iMPC sound set and classic Akai Professional sound library
• Sample from Android mic, line in or music library using multi-touch turntable interface
• 16 Levels mode: 16 levels of attack, velocity, length, and tuning
• Note Variation slider: adjust attack, velocity, length, and tuning as you play
• Trim and categorize samples, undo takes and erase samples
• Built-in effects: delay, bit crusher, master compressor/limiter
• Export your projects for use in the desktop MPC Software or in wav format

Pricing and Availability. Akai iMPC, for Android Galaxy phones and tablets, is available now as an in-app purchase from the Soundcamp app, which is available via Samsung’s Galaxy App Store. It retails for $6.99 (£5.99 UK). For more information, visit akaipro.com.

The musician Skarabee and longtime user of Caustic have released some free goodies to go with Caustic 3.2.

​Here is what is in the first pack:

2 skins: Nautilus (3.1 revisited for 3.2)
             Paisley (a purple skin in memory of Prince)
20 sawsynth presets
8 stereo PCMsynth presets 
3 stereo beatbox presets ( brushcat, fatdrums and stereopercz) 

To get this go to the Caustic forum here:
http://www.singlecellsoftware.com/node/15536

He also have a website called aptly enough Caustic Resource. Here he have released more packs that take advantage of the latest Caustic, specially stereo samples in the sampler.
So go here and you can find even more great things like Orchestral instruments, clusters, textures and beatbox presets.

To go and check it these packs that are free as well go here:
https://sites.google.com/site/thecausticsessions/causticpacks

To see some new tutorials (eleven of them) for this MPC inspired sampler with an impressive array of functions go here:

https://www.youtube.com/channel/UCCPQieH9AtSCD1O9JzgKRQA

There is also a recent update:

Whats new in 1.07?
Improved sequencer record quantise
Realtime swing to any pad recording(hold down pad + tap cursor up / down)
Realtime pad quantise change to any pad recording (hold down any pad + tap cursor left / right)
Erase Pad, Track or Sequence recording
(Any pad + option two)
1/64 and 1/64T Quantise and drum roll options added
Region chop in SampleEditor
Support for devices which support androids new low latency feature
Improvements in Note Edit
Bug Fixes...

Google Play:

https://play.google.com/store/apps/details?id=uk.incrediblesoftware.main

There definitively going to be more developers that made apps for iOS moving to Android as many of the later devices have low latency and it is unexplored market compared to iOS.
Some did already but there is lots of major players that did not, Korg being one of them.
And I guess Korg releases more of their iOS developed apps soon?

Google Play:
https://play.google.com/store/apps/details?id=jp.co.korg.kaossilator.android

*** Special Sale for a limited time to celebrate the debut of KORG Kaossilator for Android (50% OFF) until Jan 5! ***

A mobile synthesizer app for Android OS.

​The iKaossilator app for iOS became an enormous hit when it was released in 2011, and now it's available as an Android app. "KORG Kaossilator for Android" is a synthesizer app that lets anyone enjoy full-fledged instrumental performance simply by freely moving their finger across the touch panel. From electronic sounds to acoustic instruments and drums, you can play a wide range of sounds with a single finger. Also provided is a sequencer that's indispensable for creating songs, so you can create tracks by recording and layering your performances. This easy yet full-fledged instrumental experience is now available on your Android smartphone.

[Features]

​- Perform using touch gestures: Kaossilator uses the unique X-Y interface. Create melodies and phrases simply by stroking, tapping, or rubbing the touch screen with your finger.

- 150 diverse sounds covering many music styles: Use the 150 built-in sounds to perform and produce a broad range of dance music styles including EDM, hip-hop, house, techno, dubstep, nu-disco, and electro.

​- Scale/Key feature eliminates any wrong notes: The Scale setting ensures that the notes of your performance will stay in the key you’ve specified. Choose from 35 different scales including chromatic, major, minor, and even blues scales.

- Loop sequencer for easy track-making and live performance: The built-in loop sequencer lets you layer up to five musical parts. By recording sounds such as synth, bass, chords, sound effects, and drums into each part, you can quickly complete original loop tracks that are distinctively your own.

​- Operation Requirements
Android 5.0 or later
More info at korg.com

If you missed the Beta announcement...
Seems like a nice app to use if you are a sample/loop fanatic or just need a good sampler in your life. Comes with direct recording and editing in the same app so just like a real sampler then!
Comes with four different in-app purchases depending on your needs... Export/Import I guess would be a high priority for example!

​Google Play:

Remixlive

The essential app for instant remixing, powered by pro samples. Remix music with synced loops, sounds & FX.Mixvibes, the pioneer of digital DJing, introduces the perfect remix toolbox: lay down samples on a grid of pads and tweak them in seconds. Don't have any production hardware? Remixlive is all you need to turn ideas into high-quality tracks.
Want to create unique songs? Record live input through the device's microphone and capture any sound, voice or instrument. Fine-tune your samples like in a DAW production software by editing their length and envelope (ADSR). Play several samples per column in multiple mode to create rich and layered sounds.
Remixlive is optimized for live performance: change the tempo, adjust samples' tone or play them in reverse mode, all in real time!
/// PRO-SOUNDING SAMPLES
• Grid: 24 pads on mobile, 48 on phablets & tablets.
• 48 samples per pack: beats, basslines, melodies, vocals and FX samples. 
• 24 sample packs, ranging from Hip-Hop to Dubstep - and more to come. 
• Artist pack by legendary DJ/producer Carl Cox and more to be added. 
• Create new packs by mixing and matching samples from existing packs. 
• Colored pads: choose among 16 colors to customize your grid.
/// REMIX TOOLBOX
• Instant FX pad: Delay, Filter, Flanger, Reverb, and many more.
• Control levels, filters, Mute and Solo on each channel.
• Professional-sounding three-band EQ on each channel (phablet & tablet only).
• Loop your track using the different beat-repeat pads, from 2 bars down to a single beat.
• Live BPM control (time stretching): change the tempo on the fly without changing the pitch.
• Multiple Mode: play several pads per column simultaneously.
• Trigger an entire line of samples at once with a simple swipe across the screen. 
• Record your performance iMP4.
• Share your recordings via email & SoundCloud, or open them in other apps.
• Tempo tap: tap a beat to adjust the Master BPM value.
/// EDIT SAMPLES
• Edit Play mode (loop, one-shot, gate), Quantize, Gain, ADSR, Pan, Loop Division, Reverse.
• New Retrigger mode: tap on a sample to replay it from the beginning.
• Import your own samples directly from your library (MP3,WAV,Ogg,MP4,AAC/M4A, 16/24 bits, 32 seconds max). 
• Record any sound or voice through the device's mic or from​ any Android-compatible microphone or sound card. 
• Load, move and duplicate any sample, anywhere on the grid.
• Transpose: raise or lower the tone of your samples.
• Audio limiter: avoid saturation.
• Search all samples or browse samples by category: Packs, Loops, Sounds or User.

​Good addition to the Android music apps. Have been out on iOS for a while and the video in the end is showing the iOS version.
Like that it is easy laid out and can record and edit samples as well plus a decent amount of effects.
So it is possible to download the app already as Beta without having to sign up as a Beta tester.
Just go to the Play page and install:
https://play.google.com/store/apps/details?id=com.mixvibes.remixlive

Google Play info:

Try Remixlive as part of the public beta and get discounted prices on all in-app purchases!This is a beta version of Remixlive for Android, in the process of being tested before its official release and it may contain defects. Thank you for your feedback and for helping us to improve Remixlive :-)
The essential app for instant remixing, powered by pro samples. Remix music with synced loops, sounds & FX.
Mixvibes, the pioneer of digital DJing, introduces the perfect remix toolbox: lay down samples on a grid of pads and tweak them in seconds. Don't have any production hardware? Remixlive is all you need to turn ideas into high-quality tracks.
Want to create unique songs? Record live input through the device's microphone and capture any sound, voice or instrument. Fine-tune your samples like in a DAW production software by editing their length and envelope (ADSR). Play several samples per column in multiple mode to create rich and layered sounds.
Remixlive is optimized for live performance: change the tempo, adjust samples' tone or play them in reverse mode, all in real time!
/// PRO-SOUNDING SAMPLES
• Grid: 24 pads on mobile, 48 on phablets & tablets.
• 48 samples per pack: beats, basslines, melodies, vocals and FX samples. 
• 24 sample packs, ranging from Hip-Hop to Dubstep - and more to come. 
• Artist pack by legendary DJ/producer Carl Cox and more to be added. 
• Create new packs by mixing and matching samples from existing packs. 
• Colored pads: choose among 16 colors to customize your grid.
/// REMIX TOOLBOX
• Instant FX pad: Delay, Filter, Flanger, Reverb, and many more.
• Control levels, filters, Mute and Solo on each channel.
• Professional-sounding three-band EQ on each channel (phablet & tablet only).
• Loop your track using the different beat-repeat pads, from 2 bars down to a single beat.
• Live BPM control (time stretching): change the tempo on the fly without changing the pitch.
• Multiple Mode: play several pads per column simultaneously.
• Trigger an entire line of samples at once with a simple swipe across the screen. 
• Record your performance in mp4.
• Share your recordings via email & SoundCloud, or open them in other apps.
• Tempo tap: tap a beat to adjust the Master BPM value.
/// EDIT SAMPLES
• Edit Play mode (loop, one-shot, gate), Quantize, Gain, ADSR, Pan, Loop Division, Reverse.
• New Retrigger mode: tap on a sample to replay it from the beginning.
• Import your own samples directly from your library (WAV, AAC, M4A, MP3, 16/24 bits, 32 seconds max). 
• Record any sound or voice through the device's mic or from​ any Android-compatible microphone or sound card. 
• Load, move and duplicate any sample, anywhere on the grid.
• Transpose: raise or lower the tone of your samples.
• Audio limiter: avoid saturation.
• Search all samples or browse samples by category: Packs, Loops, Sounds or User.
And, last but not least, the app is universal: buy In-App Payments once and use them on your mobile, phablet & tablet.

 The collaborative and interesting application Groovecloud now allows for sample import.
This will of course allow for a much more flexible user experience!
Their developer blog is a pretty interesting place to check out as well.
http://thegroovecloud.tumblr.com/post/138088390961/191-a-world-of-new-sounds