What does a negative tilt in frequency response indicate about an amplifier's input signal?

A negative tilt in frequency response indicates that the amplifier is amplifying lower frequencies more than higher frequencies. This results in a roll-off effect as the frequency increases, meaning that as you move to higher frequency ranges, the amplitude of the signal decreases.

In this context, a negative tilt suggests that the frequency response is not flat; instead, it allows low frequencies to dominate the output. This characteristic can be particularly useful in certain audio applications where a warmer sound is desired, as it enhances bass frequencies.

When evaluating the options, it's important to note that a balanced amplitude across all frequencies would indicate a flat frequency response, which is not aligned with what a negative tilt represents. Higher amplitude at higher frequencies would be the opposite of what is indicated by a negative tilt. Lastly, saying that a negative tilt has no impact on signal quality overlooks the significant implications that such a response can have on the tonal characteristics of the amplified signal.