Re: [Harp-L] School survey help needed

[Philharpn@xxxxxxx]

Depends on the level of practice. And the purpose. Keyboard players can 
practice on a printed copy of a keyboard. Guitarists can place a cloth under 
the strings on acoustic guitars. 

If you want a really quiet harmonica, take out the reed plate. You get the 
benefit of playing against a comb without making any noise.

 This works only if you already "know" where the notes are. If you're still 
fishing for notes -- hole 5 or hole 6 --   this won't work.

Phil




In a message dated 5/3/10 12:27:51 AM, jevern@xxxxxxx writes:


> I haven't seen your designs, but I doubt that any of them will be 
> effective.
> 
> You will have great difficulty designing an effective muffler for the 
> harmonica.
> The sound level of a tightly hand-cupped diatonic will be about as quiet 
> as you can get with any practical attachment.
> 
> The human ear has a logarithmic response.  A 30 db reduction in perceived 
> sound would require reducing the transmitted sound energy to 1/1000 of its 
> normal level.  There is a story (possibly true) about the GE engineer who 
> promised his boss to reduce the sound energy from a jet engine by 50%.  He 
> did it, but the engine didn't sound perceptibly quieter.
> 
> Go out to the garage and practice in the car.  
> 
> A porous surface like cane board suppresses reflection of sound but mass 
> like masonry is required to suppress transmission.   
> A double layer of wallboard (lots of mass) on the door to your practice 
> room might work.  However, it must seal all of the tiny cracks perfectly.  A 
> hole in the door the size of a quarter would be almost like leaving the 
> door open.
> 
> Sorry to be an old killjoy but it's not me...it is the acoustical sad 
> facts.
> 
> Vern
> 
> >
> >  HeyY'all,
> >
> >  My name is Joe Glover, i am currently in Year 12 and doing Design and 
> technology as a subject. For my project i have chosen to design and create a 
> harmonica muffler which makes the harmonica quiet for practicing late at 
> night or whatever.
> >
> >  I have attached a powerpoint with a series of pictures, of the various 
> designs that i have come up with - just the shape and ergonomics really.
> >
> >  Please, if you have time could you take a look and tell me:
> >
> >  1. Which one you like the most
> >  2. Why you like it
> >  3. What you like and dislike about each of the designs
> >  4. what you would add to or take away from each of the designs.
> >
> >
> >  Thankyou for your time, it should be a bit of fun for you guys too.
> >
> >
> >  if anyone is interested,
> >
> >  the basic design is a hollow chamber in which the re-verberate and are 
> muffled by sound absorption material (quiet wave). I am hoping to cut down 
> the sound by 50%. The player can still hear it perfectly because the noise 
> comes out the holes not being played.
> >
> >
> >
> >  thankyou so much,
> >
> >  Cheers, Joe Glover
> >
> >
> >
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