Ok i have a 1983 Fender bassman 20. It is a 18 watt tube combo amp with a single 15. I have come to the conclusion that at some time someone put 2 20oz pop cap sized ports in the cab. So tonight i pluged them with pop caps And here are a few things i noticed. Amp settings are volume 5, treble 1, middle 6, bass 4. Bass wa max volume and tone was rolled off. Tone was tighter not as airy. Seemed to have more volume at same settings. Tone was more even across all te strings. Not as much touch was needed with the high strings to sound even. So what happen? 2 small holes can change things that much? What should i do? If i want to leave them pluged what is the best way? Also how do you clean dust from speaker?