What's really cool about felt strips is that you have the exact control over the amount of bass drum muffling by varying the width of the strip. I started at a 3" width for my 20" Ludwig Classic Maple bass drum, which is photographed. From there I went down to a 2 1/2" and then a 2 1/4. I finally ended up using a 2 1/8" width strip. This gives my resonant head just the right amount of muffling to get rid of the plastic sound that Ludwig's bass drum resonant heads emit when used at lower tuning tensions. This gives me a lower fundamental frequency for the drum, since I don't have to tension it as much, without critically affecting its resonance. The felt also gives a touch more focus to the bass drum's sound. My girlfriend cut various widths of felt from 3 1/2" down to 2" for my experiments. She thought that she would take over this chore so that I would still be left with five digits per hand to be able to manipulate the sticks, lol.
Those old timers knew what they were doing when they introduced felt strips to their bass drums.