Strong sound at a strong price Bring on the big fun of being there live, but leave off the big price tag — that's the idea behind JBL's Concert Series car speakers. Their Concert 621F 6-1/2" coaxial speakers deliver a strong sound with a striking design, accented by JBL's "exclamation point" logo on the tweeter. And the speaker's patented Plus One structure extends the surface area of the polypropylene woofer cone to give you a better low-frequency experience. A match for any system These 3-ohm speakers are sensitive enough that you can power them with an aftermarket stereo, but you'll get even better results feeding them power from an outboard amp.