thanks for the detailed post hifiman5. one quick question, wouldnt the
current on the speakers drop if you connect subs to them in parallel?
because current would decrease for parallely connected components right?
No, there would be no effect on the current delivered to the main speakers. When a powered sub is connected to the output of a power amplifier or integrated amplifier, what the amplifier is driving is the sub's amplifier, not the sub's driver, which means it is driving a very high impedance that will draw negligible current. The Vandersteen sub Hifiman5 referred to, for example, has a specified input impedance of more than 100,000 ohms.
A consequence of that, btw, is that the cables used to connect amp outputs to a sub that can accept speaker-level signals can be much narrower in gauge than typical speaker cables.
To address your question more generally, adding a load impedance in parallel with another load impedance will only affect the current delivered to the first impedance if the voltage across the paralleled impedances becomes different from what the voltage across the first impedance would have been in the absence of the second impedance. And that voltage will only change as a result of the addition of the second impedance if the effective output impedance of the component providing the current is high enough to be a significant fraction of the second impedance, or if the component is not capable of supplying the total amount of current that is drawn by the two loads in response to the voltage it provides.
Very few power amps or integrated amps have effective output impedances of more than a few ohms, and most solid state amps have effective output impedances of a tiny fraction of an ohm, those numbers obviously being insignificant fractions of 100,000 ohms. So none of this will be an issue with a powered sub.
Good luck. Regards,
-- Al
