6 ½ speakers can fit 6 ¾ cutouts and vice versa through adapter brackets. Those brackets make different speaker sizes suitable for varied cut-outs and bolt patterns.
Without any modification, a 6 ½ speaker fits into a cutout with a diameter of 4.8-5.2 inches. Similarly, a 6 ¾ diameter speaker goes into 5.2-5.7-inch cutouts. But if there is an adapter bracket enclosed with the speaker, it won’t make any difference if the package says 6 ½ or 6 ¾.
When it comes to fitting 6 ½ or 6 ¾ speakers in the cutout, virtually there is no difference. Both of them can fit into the same cutout. The same speaker model showing different dimensions happens due to different POVs. The manufacturer uses the speaker dimensions along with its installation components to label it 6 ½ or 6 ¾.
Meanwhile, reviewers see the speaker from the car’s perspective. If they see a speaker that can fit a cutout hole and bolt pattern for a 6 ½ size, they will call that speaker 6 ½. On the other hand, the manufacture might call it a 6 ¾ speaker after factoring in the dimensions of its brackets as well.
Last update on 2021-06-15 / Affiliate links / Images from Amazon Product Advertising API