Tuesday, March 22, 2011

Quick illustration, some lingo, and discussion about reeds

Reeds are the gizmos inside of an accordion that produce the sound. How do they work? A note is produced when air is forced through the slot and over the reed tongue by the bellows. The tongue vibrates back and forth in the slot, chopping up the air stream at a set period (the frequency of the note's pitch). Longer, thicker tongues make lower pitches and shorter, thinner tongues make higher pitches. In such a way the inanimate accordion becomes like a wizard's bird - honking and chirping at the player's command. I'm a pretty lousy sorcerer but there are some seriously powerful box wizards out there.

For more information on fancy lingo, accordion reeds, and how they work, please visit some of these recommended articles and websites:

Voices and tunings : a beginner's guide
by Steve Dumpleton

What the heck does THAT mean? (Accordion speak 101)
by Gary Chapin

 Talking reeds : accordion reeds and tuning
(independent website)

I thought I'd include a short illustration of what the reeds look like to demystify some lingo that is thrown around on accordion websites.


The above illustration features a set of brass bass reeds on individual zinc plates pinned to a leather gasket without using wax. Hohner advertised them as "bronze" or "steel bronze" reeds. The valves are also made of leather. This set (okay, it's half a set) was pulled from a Hohner two-row diatonic accordion made c.1910.

Hunh? What's all that mean? What difference does it make?

The reed tongues shown above are made of brass. Brass reed tongues produce a pleasant, sonorous tone but require more air pressure to sound off. This is one reason why most modern accordions have steel reeds. As a fellow squeezer pointed out in a comment to this post (Andy has a great accordion blog, which you can visit here), brass also work hardens differently than steel - in other words as it flexes, over time, brass becomes brittle and eventually breaks - a good argument for steel over brass. If you've ever bent a soda pop can or paper clip back and forth until severing it in half then you've experienced work hardening in action. For a reed, or perhaps for the musician in the middle of a tune, reed breakage is a catastrophic failure!

Personally, I really enjoy the tone of brass reeds. Although there is some evidence supporting that different brasses were employed at various times and by various companies, all of the brass reeds that I have played share a common mellow and buttery sound. Here is a lovely waltz composed and performed by Jan-Anders Andersson of Sweden. It is performed on an old Hohner fitted with brass reeds so you can hear how a set of brass reeds sound in the right hands.



The reed plates in the illustration are made of zinc - these are the flat pieces of metal that hold the reed tongue in place over the air stream. Sometimes reed plates are referred to as frames, shoes, or plates. I imagine there are other names, too. So why zinc? More like, why not zinc. Zinc plates are heavier than the plates in today's accordions which are often made of lightweight aluminum. Can you imagine playing a Shand Morino with all those reeds and the plates all made from zinc? You'll need a crane to hold yourself upright. Some of today's finest reed plates, like those offered by Binci, are made of brass. Because the reed is fixed to the plate at one end by a rivet, the composition of the metal used for the plate will affect the tone made by the reed. This is an area of acoustics that I am not familiar with, but it does make a difference. Discussions about how much of a difference is caused by the metal of the plate vs. other properties of the whole assembly will occasionally pop up on melodeon websites and in the conversation of melodeonists. It's an interesting topic that has a lot of different facets.

Leather gaskets were once commonly used to seal the area where the plate meets the reed block (this isn't described in the photo but you can see the gasket between the plates, sitting on top of the block). The gasket on the reed block is a strip of leather under the reed plate, preventing air from escaping around the plate during play. Many accordions use a rosin-beeswax mixture for this purpose but leather isn't dead yet. Note that the gasket on the reed block is different than the gasket which seals the area where the bellows meet the cabinet or body of the accordion. That gasket is usually made of neoprene, formerly of leather, and in the earliest accordions it was made of something like horse hair or candlewick. The advantages of modern synthetic materials like neoprene over horsehair and leather are quite obvious.

The valves in the iillustration, or ventile, are also made from leather. Leather valves are in use today but leather valves tend to curl up over time and require straightening or replacement. Small strips of spring steel, absent here, are often used to keep them laying flat against the slot. Mylar is commonly used for today's valves instead of leather but just like gaskets, leather ain't dead yet. When sounding a note, especially a low note, leather is quieter than mylar (less chance of rasping) so fine leather valves have their advantages. Some people like to use leather valves on the lowest notes and mylar valves on the rest of the set. Another alternative is to use mylar valves with multiple layers, and use valves with fewer layers as the scale gets higher. The highest reeds require no valves at all to keep them responding ideally. To clarify the vocabulary, in the United States, I have heard some players describe pallets and refer to them as valves.

Here is a photo showing steel reeds on aluminum reed plates. They are taken from a Hohner diatonic two-row probably built right before or right after World War Two. Note the curling leather valves (you can see why those springs, absent here, are so important). They're waxed in place, and also note the mixture of H and T marks on the individual plates in the same accordion.


This is what a new set of leather valves (ventile) might look like before you glue them in place. Note the small buttons and thin strips of spring steel.


I spoke with an accordion repairman and collector from Austria who told me that the leather valves used in old, fine accordions are of often a high quality and should be flattened and reused with springs whenever possible. He said that the process used to tan this leather product are no longer in use due to modern environmental restrictions. I haven't been able to verify this information anywhere but it does seem to make sense. I mean, unless it's pu-reh tea you're after, it's fairly safe to say that they don't make anything like they used to...


Mmmmm... fermented tea.... how's that for something that is completely off topic? Well, tea is my other passion. Accordions and a fresh brew are all in the same cup for me, whether it's a strong Kenilworth, a gamey Tieguanyin, or a winey first flush Darjeeling. Happy squeezing! I'm going to make some tea.

2 comments:

  1. Another reason why brass reed tongues have fallen out of favor is that as brass is repeatedly flexed over time, it "work hardens," which will eventually compromise its performance or even cause it to break!
    However, these old reeds should not be confused with steel reeds mounted on brass plates. These are available from Binci.
    -Andy

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  2. Hi again Monk,
    Are you sure that you mean "bronze"? -- I think that most of the old reeds that you are talking about are BRASS, and the Binci Ottone series are steel reeds with BRASS plates, not bronze.
    I like how you worked the part about work-hardening into the text -- good example with the can.
    -Andy

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