es, equalizers prefferred when installing subwoofers and a new stereo head unit because a subwoofer not only gives you a rock-solid bottom end, it lets you play your other speakers louder with less distortion by diverting the burden of deep bass to the subwoofer. A subwoofer is almost a necessity if you use the front speakers for imaging and the rear speakers for fill, because of the difficulty in getting decent bass from the front.