%% Parametric Audio Equalizer for iOS Devices
% This example shows how to use the <docid:audio_ref#bva9_33-1 Parametric
% EQ> block and the <docid:audio_ref#bu5xdmq-1 multibandParametricEQ>
% System object(TM) to implement a parametric audio equalizer model, that
% can run on your host computer or an Apple iOS device.

% Copyright 2016-2019 The MathWorks, Inc.

%% Introduction
% Parametric equalizers are used to adjust the frequency response of audio
% systems. For example, a parametric equalizer can compensate for biases
% introduced by specific speakers. Equalization is a primary tool in audio
% recording technologies.
% 
% In this example, you design a parametric audio equalizer in a Simulink(R)
% model. You can run your model on the host computer or an iOS device. The
% equalization algorithm is a cascade of three filters with tunable center
% frequencies, bandwidths, and gains. You can visualize the frequency
% response in real time while adjusting the parameters.
 
%% Required Hardware
% To run this example on iOS devices you need the following hardware:
%
% * iPhone, iPod or an iPad
% * Host computer with Mac OS X system
% * USB cable to connect the iOS device to host computer
% 
%% Model Setup
% 
% <<../audioequalizeriOS_model.png>>
%
%%
% The <matlab:open_system('audioequalizeriOS') audioequalizeriOS> model
% provides a choice of device (host computer or iOS device), and audio
% source (MATLAB workspace or microphone). 
% You can choose the configuration by clicking the |Configuration UI| button. 
%
% Configuration UI:
% 
% <<../audioequalizeriOS_configuration.png>>
%
%% Run Model on the Host Computer
% When you choose to run the model on the host computer, a UI designed to
% interact with the simulation is provided and can be opened by clicking
% |Host Tuning UI|.
% 
% Host Tuning UI:
%
% <<../audioequalizeriOS_hosttuning.png>>
%
% The UI allows you to tune the parameters of three filters individually,
% and view the frequency response in real time. You can also check the
% |Bypass| check box to compare the modified sound with the original sound.
%
% Click the |View Frequency Response| button to visualize the filters
% frequency response.
%
% <<../audioequalizeriOS_hostvisualize.png>>
%
%% Run Model on an Apple iOS Device
% To run the model on your Apple iOS device, you need to first ensure that
% you have installed |Simulink Support Package for Apple iOS Devices| and
% that your iOS device is provisioned.
%
% Once your iOS device is properly configured, use a USB cable to connect
% the device to your host computer.
%
% You can choose to make an iOS standalone equalizer app by
% clicking the |Deploy to hardware| button on the Simulink Editor toolbar. 
% After deployment, the
% app can run on your iOS device even when it is disconnected from the host
% computer. The parameter 
% tuning UI displays on your iOS device screen, as shown below:
%
% <<../audioequalizeriOS_slider.jpg>>
% 
% You can also run the model in |External| mode by clicking the |Run|
% button on the Simulink Editor toolbar. To run in |External| mode, the iOS
% device must stay connected to the host computer. This mode enables you to
% view the frequency response on the host computer while adjusting
% parameters on your iOS device. Frequency response will display on the
% host screen as follows:
%
% <<../audioequalizeriOS_arrayplot.png>>
%
