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Is there any difference?
Thanks in advance.
Thanks in advance.
Two-sided chest piece vs. single tunable diaphragm
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There is an entire thread on stethoscopes on here if you scroll a little further down.
Basically, the 2 or 3 sided stethoscope is the traditional one, with one side being better for listening to high pitched sounds, and one better for low-pitched sounds.
The tunable diaphragm thing was supposed to take the place of the 2 sides, but there are questions about whether the sound quality is as good.
I had Littman Cardiology III (tunable) throughout med school + residency, and then it got lost. I recently bought a 3-sided one (traditional Harvey-type stethoscope). If you ask me again in 2-3 months, I might be able to tell you which one sounds beter. I personally found some extra heart sounds and murmurs hard to hear with the Littman, so I guess now I'll see whether it was ME or the stethoscope...LOL.
Basically, the 2 or 3 sided stethoscope is the traditional one, with one side being better for listening to high pitched sounds, and one better for low-pitched sounds.
The tunable diaphragm thing was supposed to take the place of the 2 sides, but there are questions about whether the sound quality is as good.
I had Littman Cardiology III (tunable) throughout med school + residency, and then it got lost. I recently bought a 3-sided one (traditional Harvey-type stethoscope). If you ask me again in 2-3 months, I might be able to tell you which one sounds beter. I personally found some extra heart sounds and murmurs hard to hear with the Littman, so I guess now I'll see whether it was ME or the stethoscope...LOL.
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Which would you rather use to pick up a specific radio station...
a radio with an analog dial that has the numbers rubbed off, or, a radio with digital presets? Thats what its like to use a tunable diaphragm vs. a two-sided steth.
Lots of people describe the tunable diaphragm as generating 'mushy' sounds. If you think of a stethoscope as an air-tight tube (which it should be) which has a sensor (diaphragm) on one end... The sensor translates sound into vibration into air movement into movement of your TMs. So, to transmit clearly, the diaphragm needs to be tight enough to snap back into neutral position allowing the air movement to stop...and so on. The tunable diaphragm by definition doesn't do this, and so sounds mush together.
Many people don't realize that the tunable diaphragm is an old incidental discovery, not unlike the discovery that if you press down on the skin of a drum while hitting with the other hand, the pitch changes. Nearly every diaphragm is "tunable" to some extent, not just Littmann's. The research which the Rappaport-Sprague, and original Harvey stethoscopes is based on suggested using a tight floating diaphragm. Modern Littmann stethoscopes effectively put lipstick on a pig, and patented/marketed the old tunable diaphragm as new technology.
Heres a recent article on this topic. This link goes to the section discussing the efficacy of the tunable diaphragm. The gist of it is, in vivo the tunable diaphragm does not work, though in vitro (experimental simulation) it does well. Id est, the patented tunable diaphragm works only in theory. The section on 'clarity' on page 4 is also interesting. http://www.forusdocs.com/reviews/Acoustic_Stethoscope_Review_page6.htm
a radio with an analog dial that has the numbers rubbed off, or, a radio with digital presets? Thats what its like to use a tunable diaphragm vs. a two-sided steth.
Lots of people describe the tunable diaphragm as generating 'mushy' sounds. If you think of a stethoscope as an air-tight tube (which it should be) which has a sensor (diaphragm) on one end... The sensor translates sound into vibration into air movement into movement of your TMs. So, to transmit clearly, the diaphragm needs to be tight enough to snap back into neutral position allowing the air movement to stop...and so on. The tunable diaphragm by definition doesn't do this, and so sounds mush together.
Many people don't realize that the tunable diaphragm is an old incidental discovery, not unlike the discovery that if you press down on the skin of a drum while hitting with the other hand, the pitch changes. Nearly every diaphragm is "tunable" to some extent, not just Littmann's. The research which the Rappaport-Sprague, and original Harvey stethoscopes is based on suggested using a tight floating diaphragm. Modern Littmann stethoscopes effectively put lipstick on a pig, and patented/marketed the old tunable diaphragm as new technology.
Heres a recent article on this topic. This link goes to the section discussing the efficacy of the tunable diaphragm. The gist of it is, in vivo the tunable diaphragm does not work, though in vitro (experimental simulation) it does well. Id est, the patented tunable diaphragm works only in theory. The section on 'clarity' on page 4 is also interesting. http://www.forusdocs.com/reviews/Acoustic_Stethoscope_Review_page6.htm
