Delay between two audiorecorder orders?

I have the next code:

r1 = audiorecorder(Fs, nBits, chans, devs.input(3).ID);
r2 = audiorecorder(Fs, nBits, chans, devs.input(4).ID);

record(r1);
record(r2);

pause(T);

stop(r1);
stop(r2);

Where Fs, nBits, chans, devs & T are previously defined. The code runs properly, but I have a question. When I write record(r1);record(r2) the r1 recording starts before r2 recording? It's plausible because I use two different orders. The same occurs with stop orders, maybe the same delay. It is, the signals are delayed (signal r2 with respect to r1)

How can I know this time of delay? Using a sound source and 2 microphones (with sampling frequency of 96 kHz). I can't see the delay. I suppose the delay is really small.

Thank you everybody. David

[Eline Somberg]

Maybe find the lag from a crosscorrelation?

[Walter Roberson]

When you use multiple audiorecorder(), the delay between starting of two record() is not under your control, and there is no synchronization method provided.

Using

record(r1); record(r2)

instead of splitting them, would give less delay -- there is overhead at the beginning of every line in MATLAB.

The question was asked a number of years ago; these days the functions in Audio System Toolbox give better control.