Got a 3 blow on a Marine Band that won't sound if played normally. It's clean and vibrates properly if plucked. It will play if blown very softly, or if all four holes 1 to 4 are blown. Also if I blow 2 and then 3 it will sound. If I bend 3 draw and then blow it will sound But on its own it doesn't want to play. Any ideas why, but most importantly, what can i do? Being extra careful as it doesn't belong to me, trying to fix it for a mate.
First impression is that symptoms indicate it’s gapped too tight. As it’s a Marine Band it can be a little hard to observe the blow reed gaps. You either need to remove the plate or get some good lighting on the subject. You may already be ahead of me on this of course. You said it vibrated normally when plucked, so maybe you’ve already had the plate off the comb? If it’s not the gap, I’d be looking at the shape of the reed arc and how it enters the slot
Super Bee, yes I have opened it up to check it wasn't bunged up, and to the naked eye the gap seems normal with room to slide in something thin enough to pluck it. If it is the reed arc, as seems likely, what is the process of adjusting it?
you need to observe the action of the reed and how it enters the slot. if the tip of your reed appears to be sitting above the reedplate by a normal margin, there is still a possibility that the reed could be entering the slot 'belly down', by which i mean the reed may dip down along its length. if the case is severe it can present as the kind of choking situation you've described
i know that Richard Sleigh has made a video which demonstrates how to observe the reed action and take action to address it. that is a product which is available for $, it is called Hot Rod your harmonica. very informative on a range of harmonica performance topics
i think that andrew zajac may have some free video on similar topics. his site is worth a visit in any case. he has produced a lot of video which he has made freely available, and also some 'premium' video you can purchase.
Both Richard and Andrew also sell tools for this work. some of the tools are more specialised than others and if you are moderately handy you could make or find many of the tools needed for basic reed gapping and shaping.
basically if you aim for a situation where the reed enters the slot along the entire length at the same time, that should give a strong result. the reed generates sound through chopping up the air flowing through the slot, so if it shuts off and opens the entire slot in the same instant, that should be the most vibrant effect. if the tip of the reed enters first, you'll usually have a fairly weak result without a great dynamic range. you could also have the sensation that the reed is leaky. in a way a reed like this is gapped a bit higher tahn the impression it gives if you only consider the gap at te tip of the free end
if the belly enters first you could get a weak result, lacking range, but if the dip is deep enough you can also get a reed which acts like it is gapped too tightly, although the tip might seem fine.
