Re: [Harp-L] piezo and magnetic pickups



Most stainless steel is not magnetic. The type that is magnetic is the heat-treatable kind that is an unlikely choice for harmonica reeds. The other way to energise a magnetic pickup is to pass an electrical current through the string or reed. Unfortunately, there is no way to pass a current through a reed because the vibrating tip is not accessible for an electrical connection.

I posit that the signal from a magnetic pickup would not sound much like a harmonica. The pickup would sense the smooth, sinusoidal, mechanical motion of the reed. The signal would not have the overtones that a harmonica sound does. The reed tip opens and closes the slot in the plate in a very abrupt and non-linear fashion. The effect of this variation in area on the airflow generates the overtones that are characteristic of the harmonica. I doubt that the sound would be much affected by hand-cupping.

Making a magnetic pickup for a harp would require making the reeds of magnetic material and a large and expensive coil or set of coils. For the reason given above, I think that the sound produced would be disappointing.

I believe that a better mic for the harp is like the ones used by Mike Curtis and Paul Oscher for neck-rack use. The back of the harp adjoins an opening in the side of a cylinder with a mic element in one end. The sound of all the reeds is "captured" in the cylinder and picked up by the mic element. I am currently using such a mic-in-a-can that I like very much for use on my Ergonomic-Neck-Rack. Such mics/pickups would not be the choice of most players who hold their harp in their hands and make "wah-wah" sounds with their hand cup.

There is someone out there who has tried it. A few years ago, I made a reedplate with a few clockspring-steel reeds for someone who was experimenting with a magnetic pickup. I forget who it was. I never heard back from him about any results from his work.

Vern

----- Original Message ----- From: "Björn Sigurdsson" <bjosi436@xxxxxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Wednesday, March 18, 2009 3:12 PM
Subject: [Harp-L] piezo and magnetic pickups



Hello again, if you mail one mail to harp-l, it is so easy to mail one more.
Many of you just love to discuss microphones... I read and learn....


BUT WHAT ABOUT playing with piezo-pickups (for example check out
http://www.kksound.com/hotharmonica.html) COMMENTS, PLEASE!


Or whatabout my own idea: mount an over sized MAGNETIC PICKUP on an
seydel 1847 - I assume this should work!? Reeds of steel. I can not
find any
information about someone tried this, but it would surprise me if no
one have tried it! Steel strings... steel reeds... it is a very
natural thing to think, so I guess I have to miss something here?
I assume people working with the development of 1847:s have tried
this. What is the hatch? Next time I see an electric guitar I will
just hold it close to a magnetic pickup and see what happens. And if
this work, what do You think of placement. Will the covers interfere
if you place it on a cover. Most easy and out of the way of course is
to fasten a pickup on the back of the comb. But I know that magnetic
pick ups have a hard time to pick up bowed string sounds because the
string moves wrong (parallel to the pickup?) and in analogy with that
this maybe is a suboptimal placement? COMMENTS ON THIS?


--
Må Väl / Kind Regards

Björn Sigurdsson
Kompanigatan 20
58758 Linköping
+46 706 897257

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