At Townshend Audio we match the average nominal speaker impedance (around 8oHms) with the impedance of the amplifier using Isolda 'impedance matched' Speaker Cable. Here we explore the reasoning behind our cable products: https://townshendcable.com/
Our Analysis uses a test set-up to prove how mismatched speaker cables will cause audible differences between a range of cables.
Thanks for your time.
Harriet Townshend