Self-study
Support Electrical engineers have repeatedly demonstrated that the best solid-state amplifiers are indistinguishable from the best vacuum-tube amplifiers with respect to the characteristics commonly measured in evaluating the quality of an amplifier’s musical reproduction. ██████████ █████ █████ ██████ ███ ██████ ████ ████████ █████ ██████ ██████ ████ ██████ ████ ███ ████ ███████████ █████████ ████ ████ ██████ ████ ███ ████ ███████████ █████████ ████ ██ █████████ ███ ██████████ ██ ███████ ████ ████ █████ ██ █████
Structure: Counter-Argument
The author points out that electrical engineers have "repeatedly demonstrated" that there's no difference between the best solid-state amplifiers and the best vacuum-tube amplifiers with respect to "characteristics commonly measured" to assess the quality of musical reproduction from an amplifier. The author therefore rejects the claim made by some music lovers that recorded music sounds better from the best vacuum-tube amplifier than from the best solid-state amplifier: he claims they are "imagining" the difference.
Analysis: Ways to Weaken
The argument makes a major assumption: because there are no differences in the characteristics that are commonly measured to assess the quality of musical reproduction from an amplifier, the music lovers therefore cannot be hearing any differences in quality. But perhaps the music lovers are picking up on characteristics that are not commonly measured, but that differ between the two types of amplifiers. If this is true — if there are certain characteristics that are not commonly measured, but that are important to how people assess the quality of musical reproduction — this would significantly weaken the author's argument.
23.
Which one of the following, ██ █████ ████ █████████ ███████ ███ █████████
a
Many people cannot ████ ████ █████████ ██ ██ ███████ █ █████████ ██ █████ ██████ ████ █ ████ ████ ███████████ █████████ ██ █ ████ ████ ███████████ ██████████
This doesn't weaken. (A) is irrelevant, since we don't know who these "many people" are or whether they include the music lovers mentioned in the stimulus.
b
The range of █████████ ████ ███████ ██ ███ ███████ ██ ███████ ████████████ ██ ███████ ███ ███████████ ██████████ ████ ███ ███████████ ███████████
Irrelevant. The argument only talks about the best amplifiers of both kinds. So it's not relevant whether lower-quality vacuum-tube amplifiers, for example, tend to sound much worse than lower-quality solid-state amplifiers. We're not interested in the quality of musical reproduction for both sets of amplifiers overall, just in the quality of musical reproduction from the very best of both kinds of amplifiers, which are what the engineers have tested and what the music lovers are talking about.
c
Some of the ███████████████ ████ ███ █████████ ██ ███████████ ███ █████ ██████ ██ █ ████████ ██████ ██ █████████
Correct. By telling us that there are some characteristics important for how people experience music that are not among the "commonly measured" characteristics mentioned in the stimulus — indeed, that cannot be measured — (C) very effectively undermines the argument that the music lovers who claim to hear a difference in quality between these types of amplifiers must be imagining the difference.
d
Solid-state amplifiers are ████ ████████ ███ ████ ██████ ███ ████████ ████ ████ ████ ███████████ ██████████ ████ ███████ █ ██████████ ██████ ██ ██████
Irrelevant. We're not interested in these other differences between these two types of amplifiers, only in the quality of their musical reproductions.
e
Some vacuum-tube amplifiers ███ ███████ ████████ ██ ████ ███████████ ██████████ ████ ███████ ██ ███ ███████████████ ████████ ████████ ██ ███ ██████████ ██ ████████ ███ ███████ ██ ██ █████████████ ███████ █████████████
Irrelevant. It doesn't matter that "some" vacuum-tube amplifiers might be superior to "some" solid-state amplifiers with respect to these "commonly-measured" characteristics. The argument is only about the "best" of both types of amplifiers, and the stimulus clearly states that the best vacuum-tube amplifiers are indistinguishable from the best solid-state amplifiers with respect to these characteristics. Since the argument is only talking about the best amplifiers of both types, and (E) is clearly not, (E) doesn't affect the argument.