tanglovecat / mobilesynth Goto Github PK

A splash page is needed.  Starting up black is not a very nice experience.

What steps will reproduce the problem?
1. Run app on device
2. Running on device
3. Pressing any key

What is the expected output? What do you see instead?
I expect to hear something, but there is no sound.

What version of the product are you using? On what operating system?
Using version 1.1 on iOS 5

Please provide any additional information below.
(none)

None of the strings in the UI are localized.

Support an arpeggio, using the new key stack.

There should be a rate slider, and some settings that control the order (maybe 
random?)

What steps will reproduce the problem?
1. Turn off osc1
2. Turn up osc2
3. Hold any note
4. Adjust the osc2 cents slider

What is the expected output? What do you see instead?
The tone should adjust continuously as the cents increase or decrease.  
Instead, it increases like a 
step function every few cents.

The keyboard view needs some help:
1) Its too large for CoreAnimation to draw as a single UImage
2) It does not update when a key is pressed (probably needs multiple layers to 
accomplish)
3) It needs a "scroll lock" button for note slides
4) The view should start somewhere in the middle of the keyboard instead of on 
the low end.

The envelope doesn't work properly when the note enters the released state 
while during attack or 
decay.

The ability to program simple (8 note?) sequences would be terrific. Not
sure how this would fit with a monophonic model though.

What steps will reproduce the problem?
1.start the app 
2.touch the lower area of the screen - where the 
keyboard is
3.nothing happens? 

What is the expected output? What do you see 
instead?
I expect to get some visual feedback that I've pressed a 
key. Also I'd expect to hear some audio.

What version of the product are you using? On what 
operating system?
newest version from  app store. latest iPhone OS 2 
update

Please provide any additional information below.

The keyboard should stay with a default of the current octave, but also support 
lower octaves as 
well -- awesome bass!

What steps will reproduce the problem?
1. Press any key when glide mode is enabled and no other note is playing

What is the expected output? 
The note should start from its native pitch.

What do you see instead?
Note starts from the previous note's pitch.

What version of the product are you using? On what operating system?
Current on iPhone as of March 8.


Please provide any additional information below.

The filter also needs a controllable envelope.

What steps will reproduce the problem?
1. keyPress = [[KeyDownInfo alloc] init];
2.
3.

What is the expected output? What do you see instead?
leaking should release somewhere

What version of the product are you using? On what operating system?


Please provide any additional information below.

Hello Allen, the soft is leaking a little bit...
But it is a great job... 

A MobileSynth icon is needed

What steps will reproduce the problem?
1.  Press a key on the keyboard
2.  Press another key without releasing the first
3.  Release the first key

What is the expected output? 

The first note should sound at 1.  It should transition to the second at 2.
 At event 3, the second note should keep sounding until that key is released.

What do you see instead?

The first note sounds.  The second note sounds as long as the first key is
depressed.  When the first key is released the second note stops.


What version of the product are you using? On what operating system?

Current version on iPhone as of March 8.


Please provide any additional information below.

There may be difficulties handling this with the way the API sends
multitouch info, but other apps have resolved the issue.  I believe that
noise.io had a similar problem when it was released and it was resolved.

The filter cutoff frequency should probably be a log scale instead of a linear 
scale.

Use fixed point math instead for most operations.  See fixed_point.h

What steps will reproduce the problem?
1. Set glide rate to the max
2. Hit a low note
3. Hit a high note

What is the expected output? What do you see instead?
The note should continuously increase.  Instead, it sounds like a step function

This is very hard to reproduce consistently. I am using mobilesynth code in an 
early-stage iPad app and I have discovered that sometimes 
ResonantFilter::GetValue() can return a NaN value which fills the output buffer 
with maximum volume samples.

The problem seems to be that the variable y4_ in that function can occasionally 
wildly oscillate, as things attached to power functions are wont to do. Within 
three or four steps it's outside MAXFLOAT and that causes the other vars (y1_ 
and so on) to also breach their boundaries.

I have implemented a quick fix, placing this line right at the top of the 
function:

// Give the filter a whack with a hammer if it's out of control
if (isnan(y4_)) { 
            y1_ = 0.0;
            y2_ = 0.0;
            y3_ = 0.0;
            y4_ = 0.0;
            oldx_ = 0.0;
            oldy1_ = 0.0;
            oldy2_ = 0.0;
            oldy3_ = 0.0;
        }

Which appears to resolve the issue. It's not very pretty - the hammer analogy 
was deliberate - but it does the job. I haven't got to the bottom of why the 
values occasionally go wild, but because it's so intermittent and hard to 
reproduce my guess is that it only occurs at very specific points on the 
oscillator cycle, so the filter doesn't 'catch' that x value every single time.

I am setting up the synth like so:

        controller_ = new synth::Controller;
        controller_->set_osc1_level(1);
        controller_->set_osc1_wave_type(synth::Oscillator::SAWTOOTH);
        controller_->set_filter_cutoff(15000.0);
        controller_->set_filter_resonance(1.0);
        controller_->set_modulation_amount(0.0);

So no envelopes or modulation get initialised. I realise this may also be part 
of the problem since it's not the typical use case where you have some 
controllers on-screen with sensible values pre-set. Then I simply call:

        controller_->NoteOn(note)

when my app wants to play a sound (and NoteOff when it stops.)

Hope this helps. Thanks for the excellent code which is giving me a nice 
introduction to synthesis.

Tim

Frequency should shift at a variable rate when moving from one key to another.

AudioQueue was not design for low latency audio.  The audio output should be 
re-written to use AUHAL instead.

The Pitch modulation does not seem to be affected by the "Amount" knob.

What steps will reproduce the problem?
1.  With glide enabled, play two notes in succession far apart in pitch
2.  Play two notes in succession close together in pitch

What is the expected output? What do you see instead?

The glide between the "close" notes should be much faster than the glide
between the "far apart" notes.  Instead, it seems to be constant time, so
the glide rate is very slow when the notes are close.  I don't think this
is how most monophonic synths operate and it sounds strange.

What version of the product are you using? On what operating system?
Current on iPhone as of March 8.

It is easy to accidentally switch to another control pane when trying to adjust 
a slider.  Maybe the 
sliders should be vertical instead of horizontal?

It would be nice to implement some other effects:
- Ring modulation
- Delay
- Looping

It would be nice to have a graphic that represents the cutoff filter frequency, 
and resonance frequency (when that feature is added).

Modulation can cause clipping.  To reproduce:

1. Set the oscillator volumes to near 1 or more
2. Raise the modulation amount to be greater than zero

This should never cause clipping.

There should be a control section that lets you load/save set presets for all 
of the various controls