Speaker rings are the base structure in all mobile audio fiberglass subwoofer enclosures. They not only add strength and give the enclosure a starting point for it's shape, but they also provide a mounting surface for your subwoofer or speaker. These come in many sizes, and while there is no 'one size fits all' speaker ring, all speaker manufacturers use similar sizing specifications.

Many customers have questions about sizing speaker rings. The sizing is important because you want the tightest seal around your sub that you can get without having mounting issues. The outside dimension is not as critical. You need to first find the dimensions of your speaker. For an example, take a look at the JL Audio 10W6v2. The "overall diameter" listed on the specs from the manufacturer is 10.5". The "mounting hole diameter" is 9.0". You will see these two dimensions called different things. The overall diameter is also known as the outside diameter, the mounting hole diameter is also known as the inside diameter, or cutout diameter. These are the two dimensions you need when sizing your speaker rings. The "mounting hole diameter" is the size of hole that you need to have for the subwoofer to fit inside it securely. This 9.0 is a precise measurement, and you do not need any extra play 'just in case', but a 9 1/8" cutout for your speaker ring will work just fine, but it is not recommended to use a larger one than that. A 9 1/4" cutout diameter, for example, would result in a less tight seal around the sub. The outside diameter of the subwoofer can match up to the outside diameter of your speaker ring, or you can size the speaker ring as much larger as you think is necessary. Stock speaker rings from Elite Installer Supply/Elite Signs & Woodworking ebay store, for example, fit many 10" subwoofers very nicely with a 10 5/8" outside diameter dimension. You may want to increase the size of the outside diameter if you use a roundover on the ring, for example, if using a 1/4" roundover, add 1/2" on to the overall diameter dimension of the speaker ring. Sizing for flushmount rings, also known as dual-layer rings, is much the same, just with an extra dimension. The inside diameter is matched to the cutout diameter of the subwoofer. Then, take the outside diameter of the subwoofer and add 1/4" to 1/2" to that dimension to get your 'trim ring inside diameter'. This leaves a gap between the outside of the sub and the inside of the ring, which is necessary for proper mounting. The total overall diameter of a flushmount ring is determined from this dimension. If your trim ring inside diameter is 13", and you want a 1/4" thick trim ring, the overall diameter should be 13 1/2". This is the minimum thickness the ring should be, you can make the outside diameter thicker for more strength.

The next biggest question is on thickness of the rings. The MDF/Fiberglass combination contributes to the strength of the entire enclosure. 3/4" MDF is the standard thickness for single layer speaker rings for fiberglass use. However, you will find them available from 1/8" up to 1 1/2" thick, each has it's place in the mobile electronics field. Flushmount rings, are generally made to 1 1/4" thick total, 5/8" for the mount ring, and 5/8" for the trim ring. For heavy subwoofers (ex. 15" Subs, JL Audio W7, etc), thicker MDF can be used for mounting. JL Audio actually recommends using a 1 1/2" thick baffle to mount the subwoofer to because of it's weight and power. Speaker rings can be used in any thickness as spacers if you need a bit extra space to make your new speakers fit in your doors, or for that extra space behind the subwoofer in it's box.

These are the basics you need to know about speaker rings, you should now be able to properly size your speaker rings for your car audio projects!