The upper limit of human hearing is about 20 kHz, so they won’t be able to hear the signal.
This will generate it:
Fs = 44100; % Sampling Frequency
NrFreqs = 5; % Number Of Frequencies To Use
LoFreq = 33E+3; % Low Frequency Limit
HiFreq = 35E+3; % High Frequency Limit
t = linspace(0, 8, Fs*8); % Time Vector
fv = linspace(LoFreq, HiFreq, NrFreqs); % Freqency Vector
tm = bsxfun(@times, t, fv'*2*pi); % Create Time Matrix
sm = sum(sin(tm)); % Create Signal Vector
sound(sm*100, Fs) % Listen To Result
