Google Play:
play.google.com/store/apps/details?id=com.jazarimusic.voloco

Not a very exciting update but it is nice that Mikrosonic is still in the game! 
Robovox is pretty fun to use for quick and dirty sound experiments to add to songs and of all the voice changing apps this is the only one that I found satisfying...

Google Play info:
- Android 6 Marshmallow ready
- 8 new voice models added
- 10 voice models for free now
- Improved button layout for realtime, parrot, recording and play mode
- Recording time extended to 5 minutes

https://play.google.com/store/apps/details?id=com.mikrosonic.DroidVox

Have not got this one yet but will very soon as it is very interesting to have a "real" vocoder that allows for direct playing/recording in a mobile device...

Play Store info:

VOXCODER is a simple application for converting voice or text.The possible options are:
- Live
- Processing sounds from the microphone, a recording or text (TTS - Text to Speech)
- Choice of instrument processing
- Choice of the degree of processing
- Choice of notes of vocoded / multiplexed instrument (multipoint & arrangements)
- Choice of pitch
- Choice of the echo / reverb
- Real-time visualization of the frequency / spectrum (FFT - Fourier Transformed)
- Customizing his own stamp or the "pattern" that will be used for the transformation of the vocoder
- Stereo

For less powerfull phones, off the spectrum, the keyboard and get in Lo mode.

*** Be careful to reduce the volume in live mode if you don't use far and away remote speaker or headphone (we will not be responsible for any damage of your devices.) ***

IK multimedia have released a new microphone that is now the third one to connect directly with your device and this one being made to respond specifically for voice.
There is also application that looks interesting with or without the hardware microphone called EZ Voice. 
Maybe the biggest thing is that you can without paying any money is to load a track and sing on top. Otherwise there is as you can see in the image above eight effects available all related to enhance voice / vocals. Each one of the effects cost 0.89€ / 1.21 $ except the reverb that comes for free if you register.
To be honest have not tried the application much but it seems so far to be solid and can be useful for anyone that do want to keep all the production inside Android devices.
The microphone can be a good buy to as it is not to expensive and it seems that it have similarities with the iRIG Microphone that I have so it is probably of good build and can stand some abuse, it is also a bit cheaper and can see some instruments keeping in the same frequencies as a voice being treated nicely sonically.

Here is some links to the IK Multimedias website for some specifications:
http://www.ikmultimedia.com/products/irigvoice/
http://www.ikmultimedia.com/products/ezvoiceandroid/

Play Store link:
EZ Voice

So here is one more option if you want a Vocoder for Android.
This being the last option available when it comes to robotize your voice 
or for sound manipulation of other sound sources...
So there is somethings that could be good to say about this, 
but before lets take a look at the video that got made by Mr Nightradio.

It looks very complex and scary... But what you see is all the modules before they are packed into one meta module. So when you download the metamodule and connecting the sound source ( modulator ) and the sound generator ( carrier ) affecting the sound source it will look like this.

The brown module in the middle contains all the modules in the video and you connect a sampler or the vorbis player module with any kind of sound source as modulator. 
In the above picture it is a synthesizer module set with a sawtooth as a carrier / modulator. For you that is not familiar with how a vocoder works you also have to program notes for the carrier to get the sound source / voice to be affected melodically. 
There is room for a lot of experimentation with both carrier and modulator. 
It is better to use with voices but could be anything both as carrier and modulator.
But it seems that as carrier it is better to use a synthesizer with the saw tooth.
There is a earlier vocoder made as metamodule for SunVox made by Gilzad that you can download in the "download" sub header on the top of the website.
It is less effective but to his defense he did not have access to the fantastic new module sound2ctl that Mr Nigthradio uses extensively in his Vocoder.
But it can be interesting to download both and see how they did the metamodules and compare etc.
Mr Nightradio has also provided us with the SunVox file before it become packed into a metamodule so that gives you another opportunity to go in and modify to your hearts 
content and expand on the concept.

If you are really interested in vocoding I would suggest two more things that can be interesting if you have something to record into. One would be to use Caustics Vocoder module as it is easier to get good results with but you would have to go outside of the self contained workflow of one device and record out of one into for example the sampler of SunVox on another device preferably with a cable to not get the recording to noisy.
Or into a multitrack recorder. To use Caustics Vocoder you would not have to buy it as you could use the Demo version which would be without saving but in a case like this you would not be needing to save a song file anyway.
But the coolest thing you could do is to make a talkbox!
Not exactly the same as a vocoder but in my ears coming with a much more interesting and organic sound albeit less robotic. 
Have posted a video before that shows you how to very easily and cheaply make one but will post it again now. Remember that in this video he is using a synthesizer but you can use any sound source, for example a Android device...
There is a lot of videos with different designs and how to make them but this shows clearly how it works. Another video I like is a guy using his guitar as a soundsource.

Download the 3 files of Mr Nightradio's Vocoder Demo, the module construction file and the vocoder metamodule ( yes you do need SunVox which will be obvious for many readers but if you are new to the site or do not know about SunVox ):

And hey if anyone is doing something interesting with the source file or getting interesting results please share with us... musicalandroid@yahoo.com

Yes so here is a christmas song and why do I post it?
Because the vocals are  made entirely with an in- app (for free) of the vocoder for Caustic 3!
So if you did not know in the edit window where you can record and edit sound files that is accessible directly from the vocoder you go to the tools section and there is an application on the (just on your Android device not on the iOS version or the PC version) that is in the bottom left corner called Vocality. If you press this you can use any of the installed TTS voices that you have installed on your device, normally at least the Google one is there but there is more that you can buy or pay for. Open it and write the words that you want spoken manipulate the pitch and the speed of the voice and import into vocoder and you can make it sing or say whatever you are too afraid to say out loud yourself...
So again the singing in the song posted is made entirely using Vocality.
Maybe it does not sound so good but it shows you some possibilities and myself never heard it used to sing a whole song before.

So this excellent tuner with many other functions are now half price.
Over time it has won my heart and this is now my goto tuner. If you use any instrument including voice it is also a perfect tool for practicing keeping in pitch as waveform is graphically represented in a longer time than any other tuner. Plus it can keep track of your progress.
Tried it a little bit to train my vocals and even though I do not do it regularly it would be essential if I ever got serious about my singing.
Includes other useful functions to and even though there is a lot of free tuners this is worth paying for even if it was just the tuner and the way it works...

Playstore link:
Tunable

So this application have been out there for a long time and was always thinking that I wanted to make some experiments using it as an effects unit, well it did not happen until now because they first made an update that increased the usability a good deal and yesterday they announced a 50% Halloween sale that will last until Halloween night... So Guess this is a good time to finally take some time to write about Robovox.

As many of you know there is a whole lot of voice changers for Android and most of them are just simple gimmicks and not good for much. 
This one though has some functions that makes it actually useful both in performance and as a tool.
The main part of the screen is by a touch matrix  that can be fixed to chromatic scale, 
making it useful for musical purposes by playing the pitches.
One thing you can do that do only exists for one other application of this kind is that you can connect the output to speakers or or into headphones and use the microphone in your device and use sound and manipulate in real time. This comes with some latency so how useful it is in a live setting depends a lot of what you want to do. In either case it is a good way to test out your ideas. There is though a setting that gets the latency down more if you have Android 4.2 or over- My device is stuck on 4.1.2 so have not had the opportunity to try how much lower the latency goes... 
The other way is of course to record and playback what you recorded and during the playback manipulate the sound. Here is where the update gets noted as now you do not have to record first and then press playback but playback gets started as soon you touch the sound matrix and stops when you lift up your finger. This can be used to good advantage. In the sound sample made with guitar there is an example how this can be used.
Of course you also can use the recording as a virtual instrument. 
One more thing that came in the last update was the ability to record 60 seconds instead of 30 seconds as before. This makes it effectively useful as an vocoder as most verses or refrains in a song are rarely more than a minute long. You can also record directly from the device into a multi track for example but you would not be able to manipulate the sound afterwards. So for myself would prefer to record and then output the recording from the device and record that into something else.
It would be so good if Mikrosonic could implement that you could open up wav files that you already have as you can not do that now and if this was the case you could take recordings from a piece of music that you are working on and just affect the track and it would be perfect to have one affected and one without effects and work from there.
The only way to do this now would be to play the track you want into Robovox recording it into your device through the speakers and line it up with your other recording/s.
Mikrosonic says that they are thinking of implementing the direct import of wav files and hopefully they do as it would make the application much more useful.

Lastly theres the effects themselves there is 24 of them  and some of them not too useful or good but would say that there is about five or six of them that makes the application worth buying.
Think in the end that Mikrosonic should develop something in the line of Robovox but cutting out the cheese and make a good effects application for more serious work.
Do not get me wrong because you can do serious work as it is but it would be nice to have something similar that pushed it into more of a musicians/producers perspective.

So here is some Sound samples the first ones with repeating notes of three different instruments first the unaffected then the Robovoxed one, the last two ones is a Steel String guitar and lastly my voice with some different voice modules.

There is a lot of space to experiment one last thing I did right now was to record a riff of fingerstyle guitar and it sounded very interesting. But save that for another time as I have to pick up my daughter now.

Playstore link (remember that it is half price until Halloween night):
Robovox

Go here to read it:
http://www.therebelliousandroid.com/2013/07/45-second-quickie-vocality-tts-digital.html

Playstore link:
Vocality TTS

What is great with the mobile devices is when someone is coming up with new ways to use them- 
And here is one of them.
Feel ashamed to tell you all that when the app got downloaded and I tried to use it, did not understand the fundamentals and tried to use the microphone in the device resulting in no sound except the sound you play, tried different devices to no avail- 
but what the fuck, it got good reviews- 
even wrote the developer... sure that he is still laughing ti hi... 
(especially as he explains what I did wrong really clearly in the app description! But me and reading...)
No answer, so back to the video for the app- 
seeing that he is holding the fingers like boxing in the sound, so that got tried but still no success!!!
Ahhh the idiocy at play-  
Blame it all on my parents.

Finally it dawned on me that what is needed is to hold the speaker from the device as close as possible to the mouth and the whole reason that he is boxing in the sound is to get as much resonance as possible into his mouth.
So when this got figured out realized that you could actually do this with any sound!
Guess the louder you can get it the better and some sounds work better than others- 
The advantage with using this application is that the developer have figured out some of the better frequencies and also made the buttons as big as possible (going in one scale or other- eight buttons) so you can play it easier as the speaker is normally (or always?) on the back of the device. 
It does need some practice but think what you see in the official video is impressive enough to warrant a free download and go do your own experiments...

Wait hold on! 

Two thoughts more-

One:
It would probably be possible to use a small container to place over the speaker with a small tube out- not a too long a tube as the speaker on a device is not so strong and too much sound would get wasted before reaching your mouth...
Two:
You could do a prerecording of a synth or similar, 
play it back in any player and in this way not having to concentrate on playing at the same time...
Well lets add a third:
If you saw the videos from yesterdays post- 
make one and use a synthesizer from your device...

Playstore link:
Pocket Talkbox

Go here to read this very favorable review of Tunable the review is written for the iOS version but it works the same for Android.

http://beautifulpixels.com/iphone/tunable-is-a-great-looking-multi-utility-app-for-musicians/

Here is the short explanation from the Playstore-

From the creators of NodeBeat comes Tunable, the most intuitive visual toolkit for musicians.Tunable is a chromatic tuner, tone/chord generator, metronome, and recorder that helps you learn to play steadily, in tune, and on beat. Featuring a unique “tuning history” display for visualizing pitch over time, Tunable is the perfect toolkit for beginning to professional musician.


Playstore link:
Tunable

So this was on Beta and now released. The Beta did not want to work for me but this one yes and it is simple but can be useful and it is pretty funny... 
Still resisted to make it say dirty things with pitched down voice but will probably break down later in the day and go full blown Tourette!
It uses TTS (text to speech engine) that either comes with your device and if not you can download these separately, there is a lot of them some for free and some sounding better than others- as this app don't generate voices by itself it only manipulates the voice with pitch and/or speed and it makes it really easy to save as Wav. file and can even save each word separately. It is user friendly- Just type in the text in text window use the two sliders for Pitch and/or speed, press rec for the whole text or another button for the separate words. 
So if you can't rap, you can now make strange rap songs all day long! 
Or whatever automatic speech you need...
It is for free which is as always an extra bonus even though I think that he could charge a euro  or something as it is no other app like it.

Playstore link:
Vocality TTS

Developers homepage:
http://www.polynomialcsoftware.com/