I have done this on one of my Blast City cabinets. You could wait a long time or even an eternity to find some complete replacement speaker boxes. I gave up in the end and bought some modern speaker replacements (just the speakers). If your Blast was located in a smoke house the original speakers become laden with nicotine and oil and the speaker material disintegrates. I looked into re-foaming the speakers but due to size of them it was going to be impossible. I had external quotes for doing them (without guarantees or promises) but it wasn't cheap.
A replacement set seemed the best option. To replace them, I took the monitor out then carefully unscrewed two screws and carefully bent the metal strip retaining clips back on both of the speaker boxes. I then removed and opened the boxes, removed the grubby speakers, cleaned the insides and installed two new speakers in each speaker box. The ones I got were similar spec but not the same size. I could bolt them down at two positions and then glued them in for the remaining length. Reassembled the box and then installed them back in the cabinet. The sound was comparable for the speakers I bought but lacking the full bass. However, a major improvement on the sound I was getting from the old speakers. You want shielded speakers, if you go down the replacement route. I think they are 8 ohm but would need to confirm.
Honestly, I looked a long time for a pair of replacement speaker boxes- not even a hint of any.
jonhughes2021-01-15 23:27:22