Frequency responses tend to range from 20Hz-200kHz because that is the lower and upper limit of human hearing. Just because a speaker can reproduce the frequencies doesn't mean it's 100% accurate. Like headphones, speakers are configured and tuned differently. When looking for a jbl charge v charge 4 speaker, check out its sub-bass attenuation. This means that the low notes don’t sound as loud as their true sound on the respective speaker. Some speakers have this problem because the driver units are able to push air fast enough to handle the sub-bass frequencies. Most companies have passive bass radiators that use air pressure in the speaker housing. Portable Bluetooth speaker manufacturers like this technology because it's space-efficient, energy-efficient, and can be used to amplify bass notes.