Hello,
in fact, I cannot promise you that I can develop app which gives you 100% result.
But I have made application which calculates voice spectrum (see my portfolio, "Spectrum Analyzer") with high accuracy (much better than common used FFT, especially for bass-bands).
So, it can detect all harmonics of human voices, then compare their timbres; maybe it can essentially help.
At least, it is possible to estimate correlations between different voice spectra and decide if they are essentially close each to other or no.
If it is possible, I'd like to download these files with voice examples.
My additional skills: Mathematics, Algorithms etc.
No pre-payment, no forward milestones; only after completed discussion, and after delivering good result.
Thanks!