Playing rhythms in Matlab

Hello,

I am trying to create rapid sequences of notes - each note lasting as short as 0.125s in some cases - in order to play different rhythms in Matlab. However, Matlab is not playing the individual tones purely; rather, it makes several jerking/offset sounds during the duration of the individual tones. How can I get these these tones to play purely and fluidly?

I have pasted some of my code below. Thanks!

function defineVars()

    global samplingFrequency numRhythmUnits  
    global pitchRhythm  
    global pitchCue pitchTarget numToneUnits  numContextPitches
    global numTrials numRhythms numTimeStamps numPitches 
    global numUnitsPerTone numRhythmsPerTrial
    rhythmNum = 1;
    toneUnitNum = 2;
    numContextPitches = 4;
    samplingFrequency = 2000;    
    pitchCue = 622;
    pitchTarget = 698;  
    pitchRhythm = [415 440 466 493];
    numRhythmUnits = 1;
    numTrials = 16;
    numRhythms = 4;
    numTimeStamps = 32;
    numPitches = 4;
    numRhythmsPerTrial =27;
    numUnitsPerTone = 1;
    numToneUnits = numTimeStamps*numUnitsPerTone;

rhythmMatrix(1,:,:) = [1 1; 1 0; 1 1; 1 0; 1 0; 1 0; 1 1; 1 0; 1 1; 1 0; 0 1; 0 0; 1 1; 1 0; 1 0; 1 0; 1 1; 1 0; 1 0; 1 0; 1 1; 1 0; 1 1; 1 0; 1 1; 1 0; 1 1; 1 0; 1 1; 1 0; 1 1; 1 0; 0 1; 0 0]; % rhythm type, consisting of 32 timeStamps

    trialParams = zeros(numTrials,2);
    currTrialRhythm = 4;
    juliansMatrix = zeros(numTrials, numRhythmsPerTrial, numToneUnits, 1);
    counter = 0;
    for i = 1:numTrials %16 trials in total, corresponding to the 4 % unique combinations of rhythmic unit type (4) and pitch type (4)
        currTrial = i;
        for l =1:numRhythmsPerTrial % (27)
            currRhythmNum = l;
            for m = 1:numTimeStamps % (32), converting rhythmMatrix to juliansMatrix % do for every trial
                currTimeStamp = m;
                for n= 1:numUnitsPerTone
                    currToneUnit = n;
                    counter = (currTimeStamp-1)*numUnitsPerTone + currToneUnit;

if n <numUnitsPerTone && rhythmMatrix(currTrialRhythm,currTimeStamp,1)==1 ||n == numUnitsPerTone && rhythmMatrix(currTrialRhythm,currTimeStamp,1)==1 && rhythmMatrix(currTrialRhythm,currTimeStamp,2)==1 juliansMatrix(currTrial,currRhythmNum,counter,1) = 1;

                          elseif n <numUnitsPerTone && rhythmMatrix(currTrialRhythm,currTimeStamp,1) == 0 || n == numUnitsPerTone && rhythmMatrix(currTrialRhythm,currTimeStamp,2)==0   
                             juliansMatrix(currTrial,currRhythmNum,counter,1) = 0;
                          end
                end
            end
        end 
        currTrial = currTrial + 1; 
        trialParams(currTrial,rhythmNum) = currRhythmNum;
        trialParams(currTrial,toneUnitNum) = counter;
    end
    for i =1:numRhythmsPerTrial
        for o = 1:numToneUnits
            currToneUnit = o;
            if juliansMatrix(numTrials,numRhythmsPerTrial,currToneUnit,1) == 1
                Fs = samplingFrequency; % Samples per second
                toneFreq = pitchRhythm(1);
                nSeconds = 0.125;   % Duration of the sound
                y = sin(linspace(0,nSeconds*toneFreq*2*pi,round(nSeconds*Fs)));
                sound(y,Fs);  % Play sound at sampling rate Fs
            else
                Fs = samplingFrequency; % Samples per second
                toneFreq = 0;
                nSeconds = 0.125;   % Duration of the sound
                y = sin(linspace(0,nSeconds*toneFreq*2*pi,round(nSeconds*Fs)));
                sound(y,Fs);  % Play sound at sampling rate Fs
            end
        end 
    end
end

Answer 1

[Sulaymon Eshkabilov]

There are a couple small but crucial flaws in your generated audio signal.

(1) There is an index related err.

(2) Your generated signal tones are not well aligned with the final sound signal subject for display.