"... but now we’ve been able to gather five price-comparable rivals around them, it seems the Monitor Audios can impress regardless of the numeracy of their rivals." (emphasis added)
Now according to my Shorter Oxford English Dictionary numeracy is "The quality or state of being numerate; ability with or knowledge of numbers." so apparently we have speakers that can count and maybe even do sums. Personally I think WhatHiFi should be more concerned with the literacy of their journalists more than the numeracy of speakers.
PS Literacy (SOED) - The quality or state of being literate; knowledge of letters; condition in respect to education, esp. ability to read and write.