A friend just gave me a really nice set of Boston 6.5 speakers. I believe my new to me 88 IROC takes a standard rear set of 6x9's? Can that area be easily modified to accept these Boston's??? (Hopefully this isn't a stupid question)
Nitro

 

It's a piece of cake. Build an adapter that bolts into the 6x9 hole, and cut out the right size hole for the new speakers.

 

Excellent! I thought I'd better get a bit of feedback before I got my hopes up and started taking things apart! Thanks, Nitro

 

Jim, what kind of material would you suggest for the adapter? This sounds like something I'd like to do.

 

1/2" MDF, 3/8" Masonite, 3/8" ABS or any scrap wood you may have laying around the house. Just toss a little sound deadener on the panel to help absorb resonances and you'll be all set. That whole B-pillar cavity rings like the liberty bell anyway, so any adapter plate you build will be the sturdiest, quietiest part of the whole area anyway.

 

Thanks, Jim.

And does a 6.5" speaker always outperform a 6x9, making this swap a worthwhile project?

 

Always? No. A very good 6x9 will certainly outperform a low end 6.5". Even within the same product line, in many cases people may prefer the sound of a 6x9 because it'll have a better capability for deeper bass due to the larger size & mass. There are some sweet sounding 6x9s out there.

But, as a general rule, when comparing a 6.5 and a 6x9 of identical materials & construction, you'll find that the 6.5" will usually have a cleaner midrange due to less distortion and better (and more predictable) dispersion characteristics.

The biggest benefit is that by going to a 6.5" size, it opens up a whole new level of quality speakers that simply aren't available in a 6x9" format. Now instead of just low end coaxes, you can choose from high end coaxes and all kinds of component sets.