Traditionally, the source of music was from vinyl records via a turntable, a technology relatively unchanged since the 1940's. Turntables, being basic mechanical devices, have lots of resonance problems, and generate their own noises particularly in the very low bass (heard as rumble). As recording equipment of that time had limited low frequency response, it was seen to be an advantage for these frequencies to be 'filtered out' as a result of technical limitations, rather than it having been a conscious design decision. A further consequence of this limitation was to help preserve valuable amplifier power, as producing very low frequencies requires huge power outputs.