'Fast' and 'slow' are a function of the mass corner of the driver.
Think of the mass corner as a kind of horsepower-to-weight ratio for loudspeakers.
A horsepower is a unit of power equal to 746 watts or 33,0000 lb-ft per minute (550 lb-ft per second).
Specd, I am a bigger and better pedant. Horsepower is a well defined measure of power, just like Watts, which you even highlight in your own post, so your post just doesn't make any sense at all. Stricktly speaking.
I herewith put you on leave from your correction mission.
I think a Horsepower is a unit of work
You can attach your standard horse and ask it to pull your standard weight.
You and I can time how quickly the weight moves.
A direct measurement of the output power of the standard horse.
Force = Mass x Acceleration
Work = Force x Distance
Power = Work / Time
If you were to research the origins of the horsepower myth you would find that it was created for use as a standardized marketing tool in response to requests from corporate marketing departments. There was a lot of discussion preceding the invention of that word. The corps wanted something they could use in marketing their products that common, technically ignorant people could relate to, when advertising power output of their products. Since everyone in that era understood horses and the relative amount of work that a draft horse can do, the Horsepower term was invented out of thin air to fill that purpose. As you (hopefully) understand by now in your adulthood, most marketing = lying. Some things never change.
Horsepower is an arbitrary mathematics CALCULATION, derived over time, from a known measure of power (and for mechanical devices requires a divisible 5252 constant!)
Only power (force) can be directly measured. Horsepower cannot be directly measured by any device or through any scheme. Power must be measured and known first, before horsepower can be calculated.
Its an untruth to imply that horsepower is a measure of power when it cannot ever be measurable. A measured power figure can be greater than, equal to, or less than, a calculated horsepower figure, depending on implementation of device. I speak from experience, having designed and built and measured many racing motors that produced a greater measured power figure than calculated horsepower figure, and vice-versa, with horsepower calculations derived using the same time (RPM) factor and constant in each calculation. Since horsepower cannot be measured and can result in any arbitrary figure above, equal to, or below measured power figures, its a useless calculation.
Its important that we use proper terms and offer corrections when and where its shown that many are being deceived. I will continue to correct people because equating horsepower with power or force in conversation is the same as lying to people.