Spinal Tap Amps
Spinal Tap Amps
[Nigel Tufnel of Spinal Tap is showing off his amplifier to Cueball.] Nigel: These amps go to 11. Cueball: Is that louder? Nigel: It's one louder.
Normal Person: Cueball: Why not make 10 louder and make 10 the highest?
Engineer: Cueball: But 11 doesn't have any units. It's an arbitrary scale mapping outputs— Nigel: Zzzz
Smart Engineer: Cueball: For $2,000 I'll build you one that goes to 12.

This comic is in reference to the 1984 mock documentary This Is Spinal Tap about the tour of the fictional rock band Spinal Tap. Here we see lead guitarist Nigel Tufnel (a character portrayed in the movie by Christopher Guest ) explaining to Cueball how the volume dial on his amp goes all the way up to eleven . This is impressive to Nigel since guitar amplifiers generally only have ten as the maximum setting. This leads him to believe his amp is "one" louder than other amplifiers .
In reality, the loudness of an amplifier is largely dependent on how much power is supplied to its electronics.  Markings on the volume dial are merely an aspect of appearance and has no influence on the maximum achievable loudness.  The highest mark could just as easily be labelled 'Maximum', which would then accurately describe the meaning of that setting.  Thus, the phrase "goes to eleven" is often used sarcastically to mock people or statements that rely on arbitrary numbers without comparable units or context.
The comic then extends the joke by presenting three types of reactions from different people:
The title text further plays on the fact that the amp's levels are on an arbitrary scale. Many products are sold at a certain price per unit weight, volume, etc. (e.g., $2.99/lb for grapes). Nigel calculates that the $2000 cost for going up to 12 would equal to $2000 / 12, or less than $200 per unit of something, but he is unable to articulate what that "something" is, confirming the third panel observation of the normal engineer. Also, he already has an amplifier that goes up to eleven, so the one additional unit would cost him $2,000 unless he sells the old amplifier. However, he decides that it's a good deal anyway, and it looks like the smart engineer has made a sale.
[Nigel Tufnel of Spinal Tap is showing off his amplifier to Cueball.] Nigel: These amps go to 11. Cueball: Is that louder? Nigel: It's one louder.
Normal Person: Cueball: Why not make 10 louder and make 10 the highest?
Engineer: Cueball: But 11 doesn't have any units. It's an arbitrary scale mapping outputs— Nigel: Zzzz
Smart Engineer: Cueball: For $2,000 I'll build you one that goes to 12.
