I am not certain what you want to do from reading your code. My filter design procedure for a bank of filters is:
Fs = 8200; % Samping Frequency (Hz)
Fn = Fs/2; % Nyquist Frequency
pf = linspace(20,4000,17); % Passband Frequencies
cf = pf(1:end-1)+(pf(2)-pf(1))/2; % Centre Frequencies
for k1 = 1:length(cf)
[z(k1,:),p(k1,:),k(k1)] = butter(7, [pf(k1) pf(k1+1)]/Fn);
[sos{k1},g{k1}] = zp2sos(z(k1,:),p(k1,:),k(k1));
[h(k1,:),w(k1,:)] = freqz(sos{k1},512,Fs);
end
figure(1)
plot(w([1 16],:), abs(h([1 16],:)))
grid
% axis([0 0.2 ylim])
figure(2)
freqz(sos{1})
hold on
for k1 = 2:16
freqz(sos{k1})
end
hold off
This snippet just designs them and displays their transfer functions. It would be easy to add code that actually filters a signal for each filter, then store the results in a matrix. I always use the filtfilt function to do the actual filtering, since it does not induce the phase distortion that filter does.