Bass blockers can be installed on any speaker. They are essentially capacitors that filter out a certain frequency of sound. Generally, they are used to block out bass from your regular speakers, leaving the bass to be produced by only the subwoofer. The frequencies it filters are mostly the lower frequencies, which are bass notes. You can do some calculations and buy the appropriate capacitors from a hobby store. You can then connect them to your speakers.
Find out the impedance of the speaker for which you would like to make the bass blocker. The impedance is generally on a sticker located on the back of the speaker near the magnet. The impedance is the unit that is measured in ohms and it uses this symbol: Ω.
Decide which frequencies you would like to block. Most bass sounds are below 150Hz, so this is a common value to use.
Calculate the capacitor value in Farads using the following equation:
C = 1/ (2* pi * R * fc)
Where: C is capacitance in farads; pi is 3.14; R is speaker impedance in ohms; and fc is frequency cut-off or 150Hz
Use your capacitance value to purchase the correct impedance capacitors. If you cannot find the exact value, remember that capacitors add in capacitance when they are joined in parallel. So, a 250uF and a500uF capacitor can be connected to be 750uF.
Connect your capacitors to your speakers by splicing them in at any point before the signal reaches the speaker.
Use a soldering iron to connect your splices and electrical tape to cover them. Remember, if you are connecting more then one capacitor, positive terminal is joined to positive terminal and negative terminal is joined to negative terminal to keep them in parallel.