to increase the strength of sound using electricity

increase in size or effect

(to cause an income, group etc) to become larger or better

make greater; improve

(to cause something) to become larger

make or grow bigger; increase

to improve something in quality, flavour etc (using something)

improve, embellish

(to cause something) to become larger

extend, augment

to make (something) longer (in space or time)

make larger, longer

to fill (a tyre, balloon etc) with air or gas

blow up, increase

make more forceful, severe

make more forceful, severe

(to cause something) to become stronger or more determined

make more forceful, severe

to make (a profit, opportunity etc) as large as possible

blow up, increase

to make (one's estimates) too large

blow up, increase

to make (something) stronger by adding or supplying more people or material

strengthen, augment