I don't think you want Black Gate for speakers, and if you do good luck finding the high value not polar types.
I suggest that there are other good caps: Mundorf, Hovland, Auri, Sonic Cap, etc. The can be found on the net.
For larger values, parallel them, for not in circuit types , eq's for drivers etc. use Solen or Madisound's or Parts Express lower cost Polypro types. For tweets the foil variety is usually better sounding but be prepared for sticker shock!
loon
I suggest that there are other good caps: Mundorf, Hovland, Auri, Sonic Cap, etc. The can be found on the net.
For larger values, parallel them, for not in circuit types , eq's for drivers etc. use Solen or Madisound's or Parts Express lower cost Polypro types. For tweets the foil variety is usually better sounding but be prepared for sticker shock!
loon