a very simple multitouch polyphonic synthesizer. synthicity itself 1.0.1 is now in the app store.
synthicity itself is simplicity itself.
simply start it up and put your fingers on it.
it will immediately start playing.
move your fingers around,
the sounds will change pitch and timbre.
there is a simple menu
accessed simply by touching the bottom bar.
with it you can change
some characteristics of the synthetic voices.
you can clamp the frequencies
to a small number of scales.
you can change
the starting pitch and number of octaves.
you can change
the attack rate.
you can change
the decay rate.
you can change
how fast the synthesizer follows your touches.
you can add
a little delay effect.
you can set
how many simultaneous voices it can play.
you can set
how it chooses those voices.
were i to add more,
it wouldn't be simple any more, would it be?
synthicity itself is fully supported
on the iPad in all orientations and on the iphone and ipod touch.
synthicity itself. it's so synthle.
touch it with all your fingers.
while it is most interesting with the generous space provided by an ipad, synthicity runs well on iphone and ipod touches.
each touch's horizontal position determines pitch and its vertical position determines the timbre.
a voice is panned left and right in synchrony with a touch's horizontal position.
touching the up arrow or bar at the bottom for more than 1/2 second reveals a control page.
touching the stop sign immediately stops the sound.
touching the info button brings you to this web page.
touching the down arrow or the colored bar on the control panel when it is showing will hide the control panel.
attack is how long it takes for the sound to reach its highest volume after being tapped. sliding to the right will make it longer.
decay is how long it takes for the sound to reach its lowest volume after raising your finger. sliding to the right will make it longer.
slew is how long it takes for the sound to catch up to where your finger is. sliding to the right will make it longer.
echo changes the length and intensity of the echo effect. sliding to the right will make space the echos out further.
the polyphony plus (+) and minus (-) buttons change the number of simultaneous voices you can play.
the lower this number, the louder the sounds will be. the default number is 10. the maximum is 32.
the touch assignment toggle button is the least simple control.
when it shows three vertical dots (), every touch will always try to start a new voice.
when it shows a circle with a dot in it (), when you touch close to an existing circle,
it will control its corresponding voice, instead of creating a new one.
the scale picker lets you change the following:
you can impose one of these scales on the pitches:
free, no scale at all.
just diatonic, a scale like a major diatonic scale.
12 tones/oct, the standard 12 tones to the octave scale.
harmonics, the natural harmonic scale.
maj pentatonic, a five note major scale. (1/1, 9/8, 5/4, 4/3, 3/2, 5/3, 2/1)
min pentatonic, a five note minor scale. (1/1, 9/8, 6/5, 4/3, 3/2, 8/5, 2/1)
surprise, a scale with randomly chosen just intervals.
you can pick the pitch of the left side of the screen, from c3 to c5.
you can pick how many octaves range across the screen, from 1 to 4 in half-octave steps.
system settings
synthicity's icon in the settings app
settings
sample rate settings
these system settings are accessed from the official settings app. look for the synthicity itself icon and name.
a system setting allows you to show or hide guidelines, which help you find a scale's pitches.
a system setting allows you to set the sample rate, which will improve audio fidelity at the expense of polyphony.
low settings will also introduce lots of aliasing noise at higher frequencies, which you may actually want.
on an ipad 1, at best 44100 hz, you should keep the polyphony at 12 or below. at good 22050 hz, the polyphony works nicely up to 25 voices.
at fair 10025 hz and cheezy 8000, you can use all 32 voices well.
experiment to find the limits on your own devices.
hints and tips
important: iphone and ipod touch devices cannot track more than 5 touches at once!
with 6 or more touches, synthicity has to cancel all touch info, which makes all the yellow control circles disappear.
the limit on ipads is a more reasonable 11 touches.
a fast attack and slew with a short-to-moderate decay gives you a pretty standard-sounding synth sound.
set the polyphony to 1 and play it like an old mono synth. turn up the slew slightly.
the echo is interesting at a number of settings.
you can use the echo to augment the polyphony to make dense clouds of nearly similar pitches. set the octave span to 1.
set the polyphony to 2 or 3 and the scale to harmonics, 2 1/2 octaves or so to get easily controlled drones.
if you get stuck notes, the stop sign will clear that up.
as with all ios audio apps, try to run as few things simultaneously as possible in performance
synthicity itself starts up with a fairly quiet 10 note polyphony.
it gets very loud when the polyphony is lower. adjust the volume settings to avoid hearing loss!
turning on the echo also lowers the volume to accommodate more sound.
• Available in the iTunes App store
• Questions? Write to synthicity "at" jhhl.net, or go to the contact page
• Read about my iPhone development in this blog
j h h l . n e t 
), every touch will always try to start a new voice.
when it shows a circle with a dot in it (
), when you touch close to an existing circle,
it will control its corresponding voice, instead of creating a new one.
