Zoomed In, with a Pinch
Test Mode Views
Spectrum Analyzer iPad
Universal for iPhone, iPad, & iPod Touch.
Also available for Mac OS X
Sound You Can See !
Sound View is a Audio Spectrum Analyzer App. It analyzes sound from the built in microphone, or from an attached external microphone, and displays both the input signal, and the results of the spectrum analysis. The input signal is displayed in the lower view as a waveform and the spectrum is displayed in the upper view as bars indicating the strength of that frequency within the input signal.
Frequencies range from 0 hertz to 22000 Hertz or 22K, this is the range of the iPhone, iPad, iPod microphone, and also the general range of human hearing.
You can double tap either the spectrum bars, or input waveform to display only that view, fullscreen. Another doubletap will return the display to showing both spectrum and waveform. Both portrait and landscape mode are supported.
A single tap will hide and display the navigation bar & scale info.
What's New, in version 2.4
- Logarithmic Spectrum Display.
- Minor Bug Fixes.
- New Icon.
You can now see the frequency spectrum in a logarithmic scale along the X-Axis. Using this scale, allows you to see frequencies at the lower range of the spectrum better. The lower frequencies are where most human sounds are made, anything less than 5K is easily seen.
Fixed a crash on bringing the app to the foreground, after being in the background a while.
What's New, in version 2.3
- Enhanced Waveform display for greater graphic accuracy.
- Minor Bug Fixes.
When pinched or scaled to display longer spans of time, the waveform display shows a more accurate waveform for the display width.
The waveform display now displays the correct number of milliseconds for display width.
What's New, in version 2.2
- Super Clean Audio Input ! 32-Bit Floating Point Audio Codec.
By utilizing floating point audio codecs available in the iOS toolkit, Sound View now has the best audio support available from the device. This means that it works very well in both loud and quiet environments, across all iOS device types.
- Pinch gestures on the Waveform Display.
You can now pinch the Waveform display to scale it. A vertical pinch will increase/decrease the height of the waveform display, but it also acts as an input gain control. The Spectrum display will react as if the input was made louder/quieter. A horizontal pinch allows you to shrink and expand the display from 17 milliseconds to infinity.
- Pinch gestures on the Spectrum Display.
You can use a horizontal pinch on the Spectrum display to zoom in/out on the spectrum bars. You can also use a slide gesture, to move the display left and right, allowing you to see specific frequencies in detail.
Pinches are cumulative, so keep pinching.
- In App Help.
What's in version 2.1
- Spectrum Bars Expanded up to 512.
- Choice of FFT Algorithm, iOS Accelerate Framework FFT, or Original Sound View FFT.
- Minor interface updates for easier use.
What's in version 2.0
- Universal Version - Welcome iPad users !
- All iOS v 4 capable devices supported, including iPhone 3G.
- OpenGL Graphics, offers better performance and smoother display.
- Spectral Flame mode. Just because it looks so cool !
- Color gradients in spectrum bars.
- Easy to use color chooser.
- Fullscreen display for both Spectrum & Waveform displays
- This app does not work concurrently with the iPod or Music app, like the phone app, they are mutually exclusive.
Logarithmic Frequency Scale
By selecting the Logarithmic option for the H. Scale in the settings panel, you can see the spectrum with a logarithmic scale on the x-axis. This allows you to see better detail in the lower frequencies, where most human sounds are found. The logarithmic scale uses 63 bars, picked using a logarithmic method out of 512.
In the settings panel, you can select Spectral Flames, which shows the spectrum bars as flames. If you switch to landscape mode and double tap the flaming spectrum bars, you see the app display fullscreen flames which respond to the sound entering the microphone. So it's much more than a "lighter app", it has more flames, and jumps to the music in the room !
By selecting the settings gear button, the Settings view appears. I kept the test mode option available because it was fun to play around with. From here you can enable/disable the Spectral Flames and choose colors for your display
Here you can also choose between the iOS Accelerate Framework FFT Algorithm, or the original Sound View FFT Algorithm. This algorithm is used to determine the frequency bar heights displayed.
You can choose a linear or logarithmic horizontal scale. Logarithmic shows the lower frequencies best, it uses 63 spectrum bars, which for now is the only setting.
The magnification slider allows you to control height of the spectrum analyzer bars. Depending on the number of bars configured each spectrum bar represents a different number of frequencies, and therefore its value varies with the number of spectrum bars. Ideally the spectrum bar height would indicate the decibel level of that frequency, however each bar represents a range of frequencies, and it's value is a sum of their decibel levels.
The decay rate slider allows you to control how fast the bars fall back to the bottom of the display. The control gives you full control, as the far left will let the value bar fall immediately, and the far right will not allow it to fall at all.
On the next page, you can choose the number of spectrum bars and turn on or off the audio filter. The filter averages 64 full spectrum samples and removes those averages from the output. This allows some background noise to be removed from the display. The resample button allows you to control what gets sampled as background noise. With the new 32-bit floating point audio in use, the filter is mostly unnecessary, as the input is so clean, but I left it in there for more stuff to mess around with.
This app was a lot of fun to develop, and can be quite mezmerizing when used while listening to music.
Enjoy The App !!