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Back to the iOS Synth

So, I’ve tried playing this synth, essentially unaltered since June 2012 aside from a bit of iCloud-related code, in a jam session.  The results were mixed, and it only confirmed the old flaws I’ve known about since 2011.  Since that jam, I’ve been coming back to this app, and progress on it has picked up once again.  I am now in the process of tidying up the design, placing all the main features where they need to go, while doing some cosmetic work.  The slightly more technical stuff I still need to tackle include:

1.  Using iCloud synced files to actually create and retrieve synthesizer settings.

2.  Adding back the “create your own waveform” platform.  This platform is the reason the synth is called a Fourier series or “drawing synth” synth.

3.  Working on the tuning with three oscillators in play.  The highest oscillator seems to be out of tune a bit and it’s not by design.

4.  Fixing knobs and graphics.

If all goes well, the app could be released this spring, but I expect it to be more like fall 2014…. : )


A typical screenshot from Xcode as I work on this code:

Screen Shot 2014-03-06 at 1.23.40 PM


Eat, drink, sleep, breath…..Platform development!

A new direction for me is going to be embedded platform development…..  It’s going to get pushed into my synthesizer design, into my work, and into my robotics hobbies with the boys!  More on this in a few days.

Worked through iOS’s effects AudioUnit implementation!

Work has continued on this project, on and off, the last several weeks.  The interface has improved, with more controls added and with more functionality added, such as simple filter and oscillator modulation.

One area that has been a trouble spot, ever since Apple upgraded the iOS audio libraries, has been the use of Apple’s own iOSaudio effects.  As it turns out, there was a particular sequence needed to make the effects portion work.  At this point, I now have a low pass filter implemented using the effects AudioUnit in iOS.  I can also implement a number of other effects.  What this buys is simply a better optimized app, taking advantage of iOS’s inherent audio capabilities, rather than resorting to a whole lot of memory hog by my app.

However, the filters I developed earlier will still be in use, though I think I will let iOS handle things like post-process effects such as reverb, delay, chorus, etc.  I still need to hear what all of these really sound like, at least to my ear, before continuing down that path.

Below are a few shots from different parts of the synth interface.

For today, I am working on getting more knots worked out in the audio buffer callback routine.  Even though the effects AudioUnit is implemented, there seems to be some issues in the basic buffering of sound, which could be due to the effects AudioUnits expectations for stereo vs. mono modes, which amounts to making sure I have the correct buffer copy scheme in place.

Still working on this…..

On and off over the past couple of months, I have still been adding different features to the iPad synth.  Most of what I have been doing is to try and get the interface to look right, with turn-able knobs and with some on/off indicators and the like.

Overall, this project has been, and will demand, a lot more work than what I though it would require.  Here is a kind of task list, if you will:

1.  Finish the current graphical interfaces, with controls implemented 10-20 hours

2.  Finish Implementing all oscillators, modulators, and filters:  20-40 hours

3.  Finish up recording / playback function and graphical interface (including output graph):  20-40 hours

4   Finish up the “drawing” part of the waveform creation, including cleaning up the sound quality:  30-50 hours

5.  Finish up the graphical interface of the “drawing” waveform:  20-40 hours

6.  Add iCloud storage capability:  20-40 hours

7.  Add Bluetooth MIDI capability 40-60 hours

8.  Add hard-wired MIDI capability (if possible)  40-60 hours

9.  Any in-app purchases I can think of……40-60 hours

9.  Optimize:  40-60 hours

10.  Submit to Apple App Store:  40-80 hours (accounts for edits and all)

11-13 weeks of work…..I think.

Here is a screenshot of what this thing looks like at the moment:  The last bay (empty) will be a recording control interface, with the eventual output graph for the recording displaying as a pop-up.  The drawing waveform interface will show up on top of everything as a pop-up.


Goodbye Google, Hello Freedom

I decided to start getting rid of the Google services tracking my every move.  So, the blog for my on-going synthesizer tinkering are now here on  What a lot of people do not realize is that Google’s monopoly over the web is getting well out of hand, and I intend to dodge that as much as possible.

Having said that, I do hope to some day port my software ported over to Android.

For today, I am simply making scales for slider and knobs I am placing on the iOS synthesizer.  Below is a screenshot of my work in AutoDesk’s SketchBook.

We’ll see if I get around to doing much more than that today.  I have a terrible headache….

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