Does the"quality" of jumpers affect the sound?

Jmcgrogan2
All analog audio signals, regardless of their magnitude, are AC in nature. All Audio amplifiers or integrated amps connected to typical loudspeakers are designed to generate amplified versions of the incoming AC (musical) signal. Any DC should be very very low, as this will bias the woofers one way or the other.

in very bad situations, such as blown output devices in the amp, will there be massive DC on the output.

All musical instruments, in their natural state generate periodic (hence AC) waveforms. Drums generate impulses with ringing, but its still periodic.

The speakers require an AC signal or we would not hear much of anything. The transducers vibrate proportional to the AC signal, compressing and expanding the air, which in turn does the same thing to our ear drum.

John,
The "AC" that comes out of your amp is not necessarily 120Hz; it's audio band signal so it ranges from 20 Hz to 20 kHz. Maybe your thinking about wall household input frequency???

anyway, Your amp, any audio amp, in general basically modulates a DC power supply with the input waveform, to produce the amplified AC output. One could easily reverse both left and right speaker cable polarity (eg swap red/blk) and not notice a bit of difference (forget about active subs and the possible issues with phase there).

(aside-If all you heard was a 120 hz signal your power supply filter caps are probably out to lunch.)