HISSIN50 said:
Sorry to go off topic a bit. I've made rings before (for cars that never had OEM speakers in a given location) and I used plywood. What thickness, type (if there are grades or whatever) of MDF do you use for something like the front door speakers (like Badstang did)?
This should be more dependent upon your application as opposed to a single authority to what is best. When designing a box for a subwoofer it is imperative you use at least 3/4" MDF or thicker. This thickness and type of wood is the most resistant to flexing (Which is your worst enemy with a sub box).
Alternatively, if we look at the application of a door speaker, the purpose is merely for mounting since the door acts as the enclosure. In addition, door speakers don't see near the wattage that a subwoofer would. For this reason, the type of wood and thickness is not as important. I do, however, have some recommendations. Ideally I would use 3/4" MDF for this application as well. For me I feel more comfortable because of it's strength and resistance to resonation. I would not, however, deem it absolutely necessary. What is more important, is knowing the mounting depth of the speaker and your available depth before hitting something (In our cars the limitation is the window, when down). This must be taken into consideration to make sure the speakers depth doesn't interefere with the windows function. If depth is no issue, however, you could probably get away with thinner wood. Personally, I wouldn't use plywood. It would, however, probably perform without a noticable difference.
One last thing to consider is the mounting of the ring to the door. Since wood can only flex so much, often times it is hard to get a complete seal where the wood connects to the door. I recommend using either silicone or a soft formable clay to ensure this connection is air tight. It would be catastrophic to sound quality for soundwaves from behind the speaker to be resonating into the listening cabin like that.
Just my .02. If you have in interest in car audio the link in my sig to my car domain has pictures of some of my stereo install. If you have any other questions I would be more than happy to give my unprofessional and unedumacated opinion
