I like to view symphonic mixes of multiple pheromones as an orchestra. Each instrument has its own unique signature and effect, and when you start combining different instruments together, you get distinctly altered and enhanced results. Instead of just a piano, imagine adding a violin and a flute playing at the same time. The music produced takes on a much deeper, more vibrant mix that’s unique and beyond the capabilities of the original instruments alone. Now also imagine throwing in a song or a musical score to play, and you move from basic music to an adventure of the senses 
Some pheromones don’t show their effects by themselves, but rather when they are mixed with other pheromones do they reveal their true nature. That’s why it’s necessary sometimes to test them together with other pheromones that you are already familiar with the effects of. A lot of mix testing is hit and miss, but occasionally, you come across a few mixes that are outstanding, and many more mixes that, given many iterations of tweaking, become finely tuned instruments that work flawlessly each time 