Sometimes dust and animal hair can enter the Quad ESL 63 and cause arcing. I suggest disconnecting the speaker, letting it discharge for a half hour, then rapping the sides forcefully. I have had some success with this method over the years.
Let us know if this does not cure the popping. If the popping is disrupting your listening, or non-listening sessions, you may be discovering that it is time for a panel replacement, or complete rebuilding (not a bad idea if you want these things to continue to make sweet music for another 20 years or so).
for the music,
Michael
Let us know if this does not cure the popping. If the popping is disrupting your listening, or non-listening sessions, you may be discovering that it is time for a panel replacement, or complete rebuilding (not a bad idea if you want these things to continue to make sweet music for another 20 years or so).
for the music,
Michael