Open Frameworks - Trying to implement ofSoundStream from a sub class

ofApp.cpp

#include "ofApp.h"

ofApp *ofApp::_app = 0;

ofApp::ofApp() { _app = this; }

void ofApp::setup() {

}

void ofApp::gotMessage(ofMessage msg) {
    
}

void ofApp::audioIn(float *input, int bufferSize, int nChannels) {
    cout << "ofApp::audioIn " << input << endl;
}

ofApp.h

#pragma once

#include "ofMain.h"
#include "screen_photo.h"

class ofApp : public ofBaseApp {
public:
    ofApp();
    static ofApp &getInstance() { return *_app; }
    void setup();
    void gotMessage(ofMessage msg);
    void audioIn(float *input, int bufferSize, int nChannels);
private:
    static ofApp *_app;
    ScreenPhoto _photo;
};

screen_photo.cpp

#include "screen_photo.h"
#include "ofApp.h"

ScreenPhoto::ScreenPhoto() {
    cout << "ScreenPhoto Constructor" << endl;
    ofAddListener(ofEvents().update, this, &ScreenPhoto::update);
    ofAddListener(ofEvents().draw, this, &ScreenPhoto::draw);
    
    _grabber.initGrabber(640, 480);

    ofApp &app = ofApp::getInstance();
    
//    _soundstream.setup(this, 0, 2, 44100, 256, 4);
    _soundstream.setup(&app, 0, 2, 44100, 256, 4);
}

void ScreenPhoto::update(ofEventArgs &e) {
    _grabber.update();
}

void ScreenPhoto::draw(ofEventArgs &e) {
    _grabber.draw(0, 0);
}

void ScreenPhoto::audioIn(float *input, int bufferSize, int nChannels) {
    cout << "ScreenPhoto::audioIn " << input << endl;
}

screen_photo.h

#pragma once

#include "ofMain.h"

class ScreenPhoto {
public:
    ScreenPhoto();
    void audioIn(float *input, int bufferSize, int nChannels);
private:
    ofVideoGrabber _grabber;
    ofSoundStream _soundstream;
    int _channels = 2;
    int _sampleRate = 44100;
    int _bufferSize = 256;
    int _buffers = 4;
    
    void update(ofEventArgs &e);
    void draw(ofEventArgs &e);
};