Tha’ts not how caps work!!
In series they are high pass filters. If you get a 10uF cap in series, it will usually pass everything, bass to treble, but block DC.
Kind of useless in the low end.
What you want I think is a small cap which removes the bass from the top.
In series a coil (inductor) is a low pass filter but it’s not usually done.
Since most of the voltage swing is in the bass, you gain a lot more by using a high pass filter to remove signal below 80-120Hz.
Using a low pass filter on an amp will gain you a lot less.
Best,
E