B&W CDM 7NT Tweeter Adapter

This is a tweeter adapter for the B&W CDM 7NT to replace the out-of-production tweeter. This design is created for the SB Acoustics SB29RDNC Ring Radiator tweeter. This tweeter was chosen because of a few reasons. Ring radiator tweeters sound amazing, it has a similar sensitivity, a great frequency response, the tweeter uses ferrofluid, and the crossover frequency is in the tweeters expected range (Tweeter expects greater than 1.5kHz, CDM 7NT is 4kHz crossover).

Steps to build:

1. Print the part.
   1. I used Polyterra Matte Black PLA.
2. Add the heat set inserts to the four holes on the face of the adapter.
   1. I used these M3 inserts from Amazon (No affiliation).
   2. How to add the inserts.
3. Sand the part!
   1. I went from about a 150 grit to 1500 grit, sanding in small circles until it was smooth.
   2. This shows the sanded parts with the heat-set inserts and the tweeter added for a fit check.
4. Paint the part with spray paint.
   1. I found the Rust-Oleum Flat Black Painters matches closely to the plastic of the tweeter housing on the speakers.
5. Attach wire extenders to the tweeters.
   1. The speaker's tweeter leads are too short to reach the tweeter, so you'll have to add a couple of leads. I did mine a bit too long at 6in, so I would go closer to 3in.
   2. You will want to solder one end of the wire to the tweeter, and then add a 2.8mm spade connector on the other end to connect to the speaker's leads. The tweeter fits very tightly in the opening of the adapter, so you won't be able to use the female connectors on the tweeter (I tried :( ).
      1. For the spade connectors, just use a needle nose pliers and bend one of the crimps over, then the other and press tightly to make sure they are both down. Be sure that the back crimps are on the jacket to relieve stress on the wire, and the front crimps are on the wire establishing a connection.
   3. Test with a multimeter that the wires have a connection through the tweeter. You should also test the resistance of the speaker to make sure it's good.
   4. You will want to use a bit of electrical tape along the back crimps to ensure there are no shorts when the wires are in the housing.
6. Screw in the 4 M3 screws to connect the tweeter to the adapter. Should be pretty short screws.
   1. Should be something like this once done
      .
7. Remove the old tweeter and connect the tweeter's leads to the speaker's leads.
   1. Twist the housing about 30 deg to the left, then gently pull the housing out. It should just practically fall out once the housing is disconnected.
   2. There will be a gray cone behind the tweeter in the speaker. The new tweeter doesn't need that since it is a closed-back tweeter.
   3. Here's what the leads look like:
       
8. Take the adapter and line up the connectors in between the tweeter housing's connectors. Ensure the adapter is flush to the housing. Twist the adapter about 30 deg or until it can't be twisted anymore. Gently let go of the adapter to ensure it's connected.
9. Enjoy!

Final product: