Confusion implementing chebyshev type 2 band pass filter in matlab
You're using the function cheb2ord in the wrong way. Assuming that your lower stopband edge is $800$ Hz and your upper stopband edge is $2000$ Hz (note that a bandpass filter has two stopband edges, as well as two passband edges), and if the sampling frequency is $6000$ Hz, then the following command should do what you intended to do:
[b, a] = cheby2(10, 60, [4, 10]/15);
Note that for bandpass and bandstop filters, the resulting filter order is twice the number you use in the call to cheby2.