I have done this multiple times over the years having been inspired by my friend's older brother's system(this is back in the 70's) that had matching Royal speakers stacked vertically. I remember he had a Scott tube amp and a AR turntable in separate room and this system rocked. I have had mostly negative results combining unmatched pairs.
When building multi-channel systems, it's recommended to have timbre matched speakers all around. The same speaker in each channel is considered ideal to create a "wall of sound". I now apply this approach and I'm currently using two pairs of Realistic Mimimus 7's stacked vertically and wired in series in my kitchen's two channel set up. With the extra pair, I have better bass. I have large speaker sound with a small speaker footprint.
When building multi-channel systems, it's recommended to have timbre matched speakers all around. The same speaker in each channel is considered ideal to create a "wall of sound". I now apply this approach and I'm currently using two pairs of Realistic Mimimus 7's stacked vertically and wired in series in my kitchen's two channel set up. With the extra pair, I have better bass. I have large speaker sound with a small speaker footprint.