There are several places where you can find the parts and supplies needed to build your own speakers. Here are a few options:

1. Online retailers: There are many online retailers that sell speaker-building parts and supplies, such as Parts Express, Madisound, and Speaker City USA.
2. Local electronics stores: Many local electronics stores and hobby shops carry speaker-building supplies.
3. Specialty audio stores: Some stores specialize in audio equipment and may have a selection of speaker-building supplies.
4. Online marketplaces: You can also try looking for speaker-building parts and supplies on online marketplaces like eBay and Amazon.

When shopping for speaker-building parts and supplies, it's important to do your research and choose high-quality components to ensure that your speakers sound great.