Re: [Harp-L] Side VEnts

[David Payne <dave@xxxxxxxxxxxxxxxxxxxxxx>]

I actually made a video that's sort of about side vents... it talks a good deal about them and there's a demonstration on how the sound changes when you cover them up:
www.youtube.com/watch?v=uVu2TY68vbs

As far as I know, two people came up with the idea of a side vent simultaneously, Jacob Hohner and Richard Seydel Sr. Hohner was working on this with the Marine Band in the 1890s. Hohner's idea was the mouse ear, his thought was that if the coverplate could be allowed to vibrate, it would change the tone. I know this cause Jacob Hohner says in the Marine Band patent that's what he was thinking.So, instead of solidly affixing the coverplate to the reedplate, he stood it up on legs, thus the mouth ear, so you the only points of contact were along the top and at the four corners. The design was open in the back and open at the sides. This changed how sound moved, thus altered the tone, but that hadn't occured to Hohner.I think Hohner figured out that it was the side hole, not the vibration that changed the sound about 25 years later, when the redesigned the Marine Band with the side vents it has today and got rid of the Mouse ears. 
When Jacob Hohner was awarded the Marine Band Patent, RIchard Seydel Sr.'s Bandmaster patent had long since been filed and was about a year from getting the patent awarded. 
Seydel came up with the same concept as Hohner, but Seydel perfected it because he knew it was the side vent, not the vibration that altered the tone. Instead of a harmonica that was open on three sides, he mostly closed all four sides. The original Bandmaster was totally closed in the back and Seydel had two little megaphones built into the coverplates  to give it volume and gather all this tone and just spew it out the sides. 
Seyel was also using maple for the comb and, from looking at the comb itself, it looks to have been cut by hand on a bandsaw. Hohner was using peachwood, a much softer wood, which probably helped the comb cutting, because it looked like Hohner was using a less labor-intensive way to do it. Whether Hohner and Seydel chose those woods because of tone, I don't know. Hohner might have used pearwood because it was easier to cut, Seydel might have chose maple because it doesn't swell as badly as peach, I don't know. I do know that Seydel, Hohner and everybody was extremely concerned about comb swell at the time. There are numerous patents where they tried to figure out ways to lessen comb swell. 
Back on the side vents, in the 1920s or 1930s maybe, I don't know exactly when, Seydel modified the Bandmaster coverplate and made it extremely open. This is the one I have and even though it is so open... it is much more open and has a larger coverplate chamber inside than the Marine Band, there is still a much greater difference in tone with the side vents than on the Marine Band. I assume Seydel opened it up for volume. 

Dave
__________________________
Dave Payne Sr. 
Elk RIver Harmonicas
www.elkriverharmonicas.com  



----- Original Message ----
From: 46long Blake <46long@xxxxxxxxx>
To: Harp L Harp L <harp-l@xxxxxxxxxx>
Sent: Monday, April 28, 2008 12:56:17 PM
Subject: [Harp-L] Side VEnts

Quick question - apart from acoustic volume, what is the purpose of side
vents on a harp?  I know that Marine bands come with them, but now I'm
seeing some customizers creating side vents on Sp20s and Golden Melodies.

See, the thing is, I find that the side vents make getting a completely
airtight seal on a cupped mic essentially impossible. As a result, I've
taken to putting little strips of electrical tape over the side vents on my
marine bands.  Anyone else given this any thought?

- Blake

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