FMOD surround sound openframeworks

Question

Ok, I hope I don't mess this up, I have had a look for some answers but can't find anything. I am trying to make a simple sampler in openframeworks using the FMOD sound player in 3D mode. I can make a single instance work fine (recording a new file using libsndfilerecorder and then playing it back and moving it in surround.

However I want to have 8 layers of looping audio that I can record and replace one layer at a time in a live show. I get a lot of problems as soon as I have more than 1 layer.

The first part of my question relates to the FMOD 3D modes, it is listener relative, so I have to define the position of my listener for every sound (I would prefer to have head relative mode but I cannot make this work at all. Again this works fine when I am using a single player but with multiple players only the last listener I update actually works.

The main problem I have is that when I use multiple players I get distortion, and often a mix of other currently playing sounds (even when the microphone cannot hear them) in my new recordings. Is there an incompatability with libsndfilerecorder and FMOD?

Here I initialise the players

for (int i=0; i<CHANNEL_COUNT; i++) {  
    lvelocity[i].set(1, 1, 1);  
    lup[i].set(0, 1, 0);  
    lforward[i].set(0, 0, 1);  
    lposition[i].set(0, 0, 0);  
    sposition[i].set(3, 3, 2);  
    svelocity[i].set(1, 1, 1);  
    //player[1].initializeFmod();  
    //player[i].loadSound( "1.wav" );  
    player[i].setVolume(0.75);  
    player[i].setMultiPlay(true);  
    player[i].play();  
    setupHold[i]==false;  
    recording[i]=false;  
    channelHasFile[i]=false;  
    settingOsc[i]=false;  
} 

When I am recording I unload the file and make sure the positions of the player that is not loaded are not updating.

void fmodApp::recordingStart( int recordingId ){

if (recording[recordingId]==false) {  
    setupHold[recordingId]=true; //this stops the position updating  
    cout<<"Start recording Channel " + ofToString(recordingId+1)+"  setup hold is true \n";  
    pt=getDateName() +".wav";  
    player[recordingId].stop();  
    player[recordingId].unloadSound();  
    audioRecorder.setup(pt);  
    audioRecorder.setFormat(SF_FORMAT_WAV | SF_FORMAT_PCM_16);  
    recording[recordingId]=true; //this starts the libSndFIleRecorder  

}  
else {  
    cout<<"Channel" + ofToString(recordingId+1)+" is already recording \n";  
}  

}

And I stop the recording like this.

void fmodApp::recordingEnd( int recordingId ){  
if (recording[recordingId]=true) {  
    recording[recordingId]=false;  
    cout<<"Stop recording" + ofToString(recordingId+1)+" \n";  
    audioRecorder.finalize();  
    audioRecorder.close();  
    player[recordingId].loadSound(pt);  
    setupHold[recordingId]=false;  
    channelHasFile[recordingId]=true;  
    cout<< "File recorded channel " + ofToString(recordingId+1) + " file is called " + pt + "\n";  
}  
else {  
    cout << "Sorry track" + ofToString(recordingId+1) + "is not recording";  
}  

}

I am careful not to interrupt the updating process but I cannot see where I am going wrong.

Many Thanks

Answer 1

to deal with the distortion, i think you will need to lower the volume of each channel on playback, try setting the volume to 1/8 of the max volume. there isn't any clipping going on so if the sum of sounds > 1.0f you will clip and it will sound bad.

to deal with crosstalk when recording: i guess you have some sort of feedback going on with the output, ie the output sound is being fed back into the input channel, probably by the operating system. if you run another app that makes sound do you also get that in your recording as well? if so then that is probably your problem.

if it works with one channel, try it with just 2, instead of jumping straight up to 8 channels.

in general i would try to abstract out the playback/record logic and soundPlayer/recorder into a separate class. you have a couple of booleans there and it's really easy to make mistakes with >1 boolean. is there any way you can replace the booleans with an enum or an integer state variable?

Answer 2

EDIT: I didn't see the date on your question :D Suppose you managed to do it by now. Maybe it helps somebody else..

I'm not sure if I can answer everything of your question, but I can share how I've worked with 3D sound in FMOD. I haven't worked with recording though.

For my own application a user can place sounds in 3D space around himself. For this I only have one Listener and multiple Sounds. In your code you're making a listener for every sound, are you sure that is necessary? I would imagine that this causes the multiple listeners to pick up multiple sounds and output that to your soundcard. So from the second sound+listener, both listeners pick up both sounds? I'm not a 100% sure but it sounds plausible to me.

I made a class to create sound objects (and one listener). Then I use a vector to store the objects and move trough them to render them.

My class SoundBox basically holds all the necessary things for FMOD

Making a "SoundBox" object and adding it to my soundboxes vector:

SoundBox * box = new SoundBox(box_loc, box_rotation, box_color);
box->loadVideo(ofToDataPath(video_files[soundboxes.size()]));
box->loadSound(ofToDataPath(sound_files[soundboxes.size()]));
box->setVolume(1);
box->setMultiPlay(true);
box->updateSound(box_loc, box_vel);"
box->play();
soundboxes.push_back(box);

Constructor for the SoundBox. I use a similar constructor in the same class for the listener, but since the listener will always be at the origin for me, it doesn't take any arguments and just sets all the listener locations to 0. The constructor for the listener only gets called once, while the one for the Sound gets called whenever I want to make a new one. (don't mind the box_color. I'm drawing physical boxes in this case..):

SoundBox::SoundBox(ofVec3f box_location, ofVec3f box_rotation, ofColor box_color) {

_box_location = box_location; 
_box_rotation = box_rotation;
_box_color = box_color;

sound_position.x = _box_location.x;
sound_position.y = _box_location.y;
sound_position.z = _box_location.z;
sound_velocity.x = 0;
sound_velocity.y = 0;
sound_velocity.z = 0;

Then I just use a for loop to loop trough them and play them if they're not playing. I also have some similar code to select them and move then around.

for(auto box = soundboxes.begin(); box != soundboxes.end(); box++){
    if(!(*box)->getIsPlaying())
        (*box)->play();
}

I really hoped this helped. I'm not a very experienced programmer but this is how I got FMOD with multiple sounds to work in OpenFrameworks and hope you can use some of it. I just dumped as much of my code as I could :D

My main suggestion is to make one listener instead of more. Also having a class for making the sounds is useful if you, for instance, want to relocate the sounds after the initial placement.

Hope it helps and good luck :)