No cross-correlation between same signal recorded using two different microphones
This answer is now obsolete.

I still keep it, because future searchers might come here with similar problems. 

This is not the signal as it is now, but as it was before, when I answered:



I'll do a hypothesis: the autocorrelation peaks are due to periodicity in your signal. But if that's the case, they should be the same for $R_{11}$ and $R_{22}$.

My guess is that you're comparing two recordings of different sampling rate (for example, 44.1 vs 48 kHz). But xcorr only sees the vector of numbers and doesn't know about the sampling rate!