If standard eq knobs on a stereo boost or cut the amplitude of specific frequencies does the volume knob adjust the amplitude of all possible frequencies?
Is there a range of frequencies different stereos have or is there a standard frequency range all stereos use?
Many stereos will generically say their range is from 20hz - 20kHz or somewhere close. This is the range of average human hearing. Each stereo will list somewhere it's frequency response. This is often done in a chart of some kind. In general the increase in volume by adjusting the volume knob would increase all frequencies in the "frequency range" by the same amount. Only a very poor stereo would increase certain frequencies more than others.
In theory a master volume knob increases all frequencies by an equal amount. Some stereos will have different frequency responses so consult the manual for that. Another factor is that human hearing is attuned to hear particular frequency ranges. Turning the master volume up will disproportionately increase the perceived volume of those frequency ranges compared to the rest of the spectrum.
