You need to factor in efficiency. Cheaper amplifiers have lower efficiency. Zenon & s&i built amplifiers are more geared toward SPL where people have upgraded alternators and are usually generic designs. Buying from a quality company that designs their own boards in house and has real engineers is a good idea. Will you hear a difference? Maybe not a huge one but I would say better damping factor, efficiency, and longevity would be the 3 biggest benefits of going with say a JL, Rockford Fosgate, ARC, audiotech Fischer, etc. as opposed to a sundown, skar, VFL audio, American bass, soundquebd, etc...I’ve seen a billion threads on class A/B amps, but a class D sub amp? Clean power, damping factor, THD, dynamic power, zenon Vs Zeff does this matter much on a bass note?
LOL. I was thinking of that article when reading this thread. I think it could be a combination things but mostly the cheaper amps just being slapped together with no thought of what component is being used or how it’s going to work with other components in the circuit. Could be power supply, S/N , THD, crappy pre amp stages. Damping factor if it’s below a certain point... I have a hard time believing the sundown is 150 considering almost all s&i built amplifiers claim 150 damping exactly.