Celestion DL4 Series Two

Like the sound of these vintage speakers but would like to add a sub,powered if needed to match a HAFLER DH220 amp.Older if possible,but newer would be fine for $200 or less.Any ideas would be great,thanks.
No help or info?
According to the specifications, these have a bottom end of 70 Hz and are relatively inefficient @ 89 dB. That means the bass probably starts rolling off somewhere around 80 to 90 Hz. I'd suggest you look for a powered sub with adjustable crossover in 10" or 12". There are several out there, but you may have to search for a while to find one in good shape at your price point.

Good luck & happy listening!