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I think the {} at the end of the error message is the hint.

Try changing

tone1 = Table[sig[t, {sf*1.0}], {t, 0,timerange, nyquist}];
tone2 = Table[sig[t, {sf*1.2}], {t, 0,timerange, nyquist}];
tone3 = Table[sig[t, {sf*1.4}], {t, 0,timerange, nyquist}];
tone4 = Table[sig[t, {sf*1.6}], {t, 0,timerange, nyquist}];

to

tone1 = Table[sig[t, sf*1.0], {t, 0,timerange, nyquist}];
tone2 = Table[sig[t, sf*1.2], {t, 0,timerange, nyquist}];
tone3 = Table[sig[t, sf*1.4], {t, 0,timerange, nyquist}];
tone4 = Table[sig[t, sf*1.6], {t, 0,timerange, nyquist}];

and see if that fixes the problem.