Reed Failure & Gapping

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  • #1351
    AvatarAlan Brinton
    Participant

    This video is about harmonicas but has useful information, I think, pertaining to the melodica. The technician explains that hard blowing can cause hairline fracture in a reed, thus causing it to fail or go seriously flat. A reed may also fail to sound because the reed is too close to the reed plate, in which case the reed needs to be gapped. There are special tools for this, although a poster on a harmonica forum says that a business card will suffice as a gapping tool. The reed has to be bent up ever so slightly. I attempted this on a melodica once, suspecting such an issue, and the reed snapped, but I was using a piece of paper and exerting too much pressure, I’m sure, from beneath the end of the reed. I have a Yamaha pianica apart at the moment, and I see that the gapping of the reeds is not entirely uniform; also, the lower notes (larger reeds) for the most part have larger gaps.

    #1356
    AvatarKevin
    Participant

    Hi Alan,
    It makes sense that the gaps in the reed plates are not uniform. The larger lower notes are going to be vibrating at a slower rate to the point they may even whip around a little so they would need a wider gap so as not to contact the edge of the plate.
    I haven’t snapped a reed yet gapping but I have bent the tongue up so far the reed would no longer sound and once also caught my shim on the end of the tongue when trying to slip it under and crunched it up like an aluminum can(a very sad day)
    Blowing really hard will flatten a reed. In fact I’ve used this technique for tuning. If I’ve worked on a reed and find when I put the cover back on that it’s still just a hair sharp I will overblow very loudly on that one note and it will usually bring the frequency of that reed down into pitch.

    #1358
    AvatarAlan Brinton
    Participant

    Thanks for your response, Kevin — informative as usual.

    I noticed that the more I’ve been playing my new P-32D, the less trouble I have with the C key that was not always sounding. And I have worked on that note. The air flow in your melodica, though, is from the top down, pushing the reed toward the reed plate, right? So it flattens the reed in another sense, flattening against the reed plate and thus narrowing the gap. So does changing the gap tune the reed, flattening it by narrowing the gap, and sharping it by widening the gap.

    When I commented about the gaps not being uniform, I meant that there were slight variations along the keyboard, in addition to the fact that the gaps increase relative to the size of the reed.

    I got a Suzuki M-32C today, shipped from Japan. It seems very nice. I noticed a few things right away. 1. There’s no indication of where it was made on the melodica itself — My STUDY 32 is clearly marked “MADE IN CHINA.” The emblem on the case, though, says “M-32C Japan”, 2. It is heavier (at 759g) than The Yamaha P-32D (656g) and much heavier than the Suzuki STUDY 32 (597g). I know the tray is made of metal. 3. The C4 key has a “C” on it. This marking is the same as on my Soprano Mylodica, so I believe that The Soprano Mylodica has a Suzuki in it. I’ll write a review after I’ve used it for awhile.

    #1363
    Daren BanarsëDaren Banarsë
    Keymaster

    Thanks for the video Alan – very interesting.

    I had a reed fail on a P37D. It suddenly went very flat, and when I went to adjust the tuning with a scraper, it bent very easily, and snapped off. I will try replacing that tongue at some point – I’ll post the results!

    Thanks for the weights for the Study 32, P-32D and M-32C – I’ve updated the database.

    #1372
    Avataralbalex
    Participant

    hi
    is what I noticed when I blow strong in my Pianica 37D …. the sound will stop but only in the eighth medium-low …..

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