Could’ve stood to hear just a little more…
Yet going with BT and G-Mans suggestions, you’ll have to remove the covers and do some tests of elimination.
Remove the Top Blow Side cover first. Play 2 Draw. Does it still make the sound?
Put Top cover back on; remove Bottom Draw side cover. Play 2 Draw and listen for the sound.
Remove both covers; play again and listen for the sound.
You may find the sound on 1, but probably not 2 & 3.
With both covers off, plink the 2 Draw Reed with a toothpick or something similar to see if it is loose or cracked. A sharp vibrating sound will be right; a dull plunk thud sound will not be.
If all is okay, check the gap ratio on the 2 Draw Reed, and also the 1 Reed.
You may have to close them down slightly. (Search through our members’ maintenance topics on how to do this.)
Put both covers on, reassemble and play the harp again. Does this make a difference?
If so, problem solved.
If not, the Draw 2 (and even Draw 1) reed can be hitting the cover.
As a final resort, remove the covers; and with a thin slice of surgical/medical tape using an exacto knife, razor blade or something similar, on the Draw reed(s) carefully affix the strip lengthwise from below the tip free end and just above the rivet closed end.
At the same time, with your thumb and fingers or even a small jeweler’s hammer or something similar, you’ll have to push out or reshape the bottom cover slightly from the inside out where the 1/2/3 Draw reeds sit. It doesn’t take a lot of pressure to remold this part of the cover, as you don’t want to bend it out of shape whereby you can’t screw it back together. In any event…
Reassemble and play again.
This should solve the problem.
The tape acts as a reed dampener and keeps it from vibrating up to the cover; and it will not affect the overall sound of the reed.
In the final analysis: If the reed plunks when you plink it, it’s a bad reed, and needs to be replaced. If it plinks, and works after you dampen it and reshape the cover, it’s a rather common occurrence, especially during the Hohner manufacturing phase.
Same thing happend with my Golden Melody G until I fixed it.
So don’t quote me, but perhaps 1 in 1000 or 1 in 5000 or more harmonicas have been known to do this; and it’s really no big deal to correct.
Hope this helps!
Keep On Harpin’!