Simultaneously play and record a signal with audioPlayerRecorder

I need to play and record a sinesweep signal selecting input and output audio card channels and the folder where it should save the recording.

I am trying to use audioPlayerRecorder I have seen its tutorial page, but it is not clear how to properly set the IN/OUT channels and how to make it works...

Moreover, once I create the sinesweep signal, I save it on the disk and I use dsp.AudioFileReader to open it as in the tutorial page. Is it possible direcltly to play the generated signal without saving on the disk?

Here is the code:

%% SIGNAL GENERATION
Fs = 44100;
sweep = sweeptone(2,1,Fs);

% Save it on disk
fileName = 'SineSweep.wav';  
disp('Save file on disk...')                    
audiowrite(fileName, sweep, Fs);

%% AUDIO CARD CHANNEL ID INPUT & OUTPUT SELECTION
info = audiodevinfo;

% OUTPUT
msg2 = "Output Channel Selection";
opts2 = string(zeros(1, length(info.output)));
for i = 1:length(info.output)
    opts2(i) = string(info.output(i).Name);
end 
choice2 = menu(msg2,opts2);
disp(opts2(choice2));

for i = 1:length(info.output)
    if choice2 == i
        ID_device_output = double(info.output(i).ID);
    end
end

% INPUT
msg3 = "Iutput Channel Selection";
opts3 = string(zeros(1, length(info.input)));
for i = 1:length(info.input)
    opts3(i) = string(info.input(i).Name);
end 
choice3 = menu(msg3,opts3);
disp(opts3(choice3));

for i = 1:length(info.input)
    if choice3 == i
        ID_device_input = double(info.input(i).ID);
    end
end
disp (['Output Audio Channel ID: ', num2str(ID_device_output)]);
disp (['Input Audio Channel ID: ', num2str(ID_device_input)]);
clear choice2; clear msg2; clear opts2;
clear choice3; clear msg3; clear opts3;

%% PLAY & REC -> my problems are in this section...
fileReader = dsp.AudioFileReader('SineSweep.wav', ...
    'SamplesPerFrame',512);
fs = fileReader.SampleRate;

fileWriter = dsp.AudioFileWriter('SineSweep.wav', ...
    'SampleRate',fs);

playRec = audioPlayerRecorder(Fs,'BitDepth','8-bit integer');

playrec.PlayerChannelMapping = [ID_device_output,ID_device_input]; % it does not work...

while ~isDone(fileReader)
    audioToPlay = fileReader();
    
    [audioRecorded,nUnderruns,nOverruns] = playRec(audioToPlay);
    
    fileWriter(audioRecorded)
    
    if nUnderruns > 0
        fprintf('Audio player queue was underrun by %d samples.\n',nUnderruns);
    end
    if nOverruns > 0
        fprintf('Audio recorder queue was overrun by %d samples.\n',nOverruns);
    end
end

Answer 1

[Sulaymon Eshkabilov]

Yes, you can read or listen your created sound or existing one using sound() fcn, e.g.:

Fs = 44100;
sweep = sweeptone(2,1,Fs);
sound(sweep, Fs)

[Lorenzo Lellini]

Thank you for your answer but I need to simultaneously play from a specific audio device channel and record from another one. I am currently not be able to manage the audioPlayerRecorder tool. I don’t know if there is another way for doing that…

Answer 2

[Jimmy Lapierre]

To specify IN/OUT channels, use channel mapping. For example, to play on channels 1+2, and record on 4:

audioPlayerRecorder("PlayerChannelMapping",1:2,"RecorderChannelMapping",4)

To avoid using a file for the sweep, consider using dsp.AsyncBuffer.

buf = dsp.AsyncBuffer(size(sweep,1));
write(buf,sweep);

You can then read it bit by bit:

audioToPlay = read(buf,512);

[Jimmy Lapierre]

Starting with R2025a, the new audiostreamer object is the easiest way to do measurements like this.

For example, to measure an I.R. with an ASIO device using channel 3 (in and out):

fs = 44100;
as = audiostreamer(Mode="full-duplex",SampleRate=fs,...
    Driver="ASIO",PlayerChannels=3,RecorderChannels=3);
sweep = sweeptone(2,1,fs);
rec = playrec(as,sweep);
ir = impzest(sweep,rec);
t = (1:length(ir))/fs;
plot(t,ir)