4 ms·

Hmmm. Looking at: https://journals.plos.org/plosone/article/figure?id=10.1371/journal.pone.0193087.g001 https://journals.plos.org/plosone/article/figure?id=10.

Hmmm. Looking at: https://journals.plos.org/plosone/article/figure?id=10.1371/journal.pone.0193087.g001 https://journals.plos.org/plosone/article/figure?id=10.1371/... I'm not sure I believe the graphs. For example, here's another frequency response chart of some stethoscopes: https://www.researchgate.net/figure/a-Frequency-response-of-Littmann-3200s-bell-mode-vs-Eko-Cores-cardiac-mode-and_fig3_368568555 https://www.researchgate.net/figure/a-Frequency-response-of-... How is it that professional stethoscopes can be that different, and yet this 3D printed one can match a gold-standard one almost exactly? From what I can tell there's no audio engineering / modelling that's been done here -- It's just some crude openSCAD tubes. And it's not even optimized for 3D printing; a 3D printed tube with a circular cross-section is going to have bridging issues at the top which will result in internal roughness. I have to imagine that results in attenuation. (A better internal shape for a tube is something that looks like "ô". The ^ will print much better) The type of plastic used and its frequency response, the thickness / stiffness of the silicone tubing, the height / width of the bell... There are so many variables that I think would make significant differences in performance. The fact that they see basically no difference is highly suspect. This feels like one of those "3D-print everything" fads that was popular a few years ago. Yes, you can make a 3D-printed adjustable wrench, but even the most miserable dollar-tree metal version will beat it in every possible metric. Likewise, on Alibaba, if you order 200 pieces, I'm seeing metal ones as low as $1.22/pc. I don't believe that this 3D printed one will even be as good as those.

rustyhancock 5mo ago
It's a bit of a head scratcher. It would require abject incompetence on the part of jellybean stephoscope manufactorers for this to make sense. On the other hand the reason Litmann stephoscopes are expensive is target market (doctors), build quality and amortization of cost over probably a decade of use. Stephoscopes are a metanym for doctor, and doctors don't want cheap stephoscopes. It reminds me of the product to make budget incubators for developing markets. I can't find a link but it failed for two reasons, if you can't afford medical grade systems. You probably don't have the highly trained teams needed anyways. Medicine is in large part a trust based endeavour you need to trust the system you are putting your life at the hands of. Long story short, this solves an imagined problem. When you consider why X doesn't have Y medical system. It's not because of the price of the kit. It's the entire system that is too expensive. If you can't afford a brand incubator you probably can't afford the it intense cleaning regime needed for the room to put that incubator in!
- khazhoux 5mo ago
  metanym (taxonomy) A name that is rejected because a valid name (based on another member) already exists for the same group.
  - ButlerianJihad 5mo ago
    metonymy (rhetoric) The use of a single characteristic or part of an object, concept or phenomenon to identify the entire object, concept, phenomenon or a related object. https://en.wiktionary.org/wiki/metonymy#English https://en.wiktionary.org/wiki/metonymy#English
- davikr 5mo ago
  Yes, if you're going to be using it for the next 10 years, it is worth going for the more expensive Littman if you can. However, I've heard that there are decent Chinese clones, and honestly I've used those $1 stethoscopes in isolation units and they're not terrible for basic pulmonary auscultation.
  - copperx 5mo ago
    But where do they fail? What does a good stethoscope bring? better and clearer amplification?
    - throwaway2037 5mo ago
      Yeah, that comment also sent off internal alarms for me also. It would be a great blog post (or YouTube video) for someone to buy a bunch of stethoscopes and objectively test them. I would bet that there is a 10 USD model that is 98% as good as 200 USD models from 3M Littmann. And similar to the neverending arguments about "premium high-fidelity stereo equipment", I bet most doctors cannot tell the difference between the two when the logo/brand is hidden. BTW: I found the 3M Littmann page on Amazon. The prices are wild: https://www.amazon.com/stores/3MLittmannStethoscopes/page/42802ABB-C5E1-4417-8239-4EB5412FA75E https://www.amazon.com/stores/3MLittmannStethoscopes/page/42...
f1shy 5mo ago
You can measure all the parameters you want. The question is: does it really matter? I know many doctors, and one of my favorite questions is about stethoscopes: I have unanimously the answer "I could just roll a piece of paper and if the room is quiet enough, I can do my work". My grandpa used one made out of wood, just a cone. Once, I was fascinated by a Littmann, with bluetooth audio, I told a friend doctor, that would be great (thinking about a present) the answer was "That is all hype, I can do with a $2 piece exactly the same". I pointed out the possibility to record the sound, to possibly defense in case of being sued: she laughed out loud, said is unpractical to record everything, would take too much time, and again, just a toy.
- morkalork 5mo ago
  Lots of nurses and EMTs swear by the amplified Bluetooth stethoscopes but unlike a Dr working in a nice quiet office, they're often in much noisier conditions.
  - bombcar 5mo ago
    The difference between a $100 mic and one that costs ten to a hundred times as much is not how well they work in perfect conditions, but how well they work in the worst conditions imaginable. Doctors often have the seniority and authority to make the room quiet; nurses and EMTs are often working in much different conditions.
- matheusmoreira 5mo ago
  > I could just roll a piece of paper and if the room is quiet enough, I can do my work That is true. The job is certainly doable. It's also possible to press one's ear against the patient's body to directly listen to the sounds without any tools whatsoever. Stethoscope was itself invented because a male doctor doing that to a woman's chest was uncomfortable for obvious reasons. There is some kind of difference between a good littmann and a cheap stethoscope. My experience is that the important sounds are just easier to hear with the littmann. Would love to know why that is, and why the cheap ones just can't seem to match it.
- dlcarrier 5mo ago
ZiiS 5mo ago
That label the graph "log dB" which seems a very odd choice if you wanted to show differences

rustyhancock 5mo ago

It's a bit of a head scratcher. It would require abject incompetence on the part of jellybean stephoscope manufactorers for this to make sense. On the other hand the reason Litmann stephoscopes are expensive is target market (doctors), build quality and amortization of cost over probably a decade of use. Stephoscopes are a metanym for doctor, and doctors don't want cheap stephoscopes. It reminds me of the product to make budget incubators for developing markets. I can't find a link but it failed for two reasons, if you can't afford medical grade systems. You probably don't have the highly trained teams needed anyways. Medicine is in large part a trust based endeavour you need to trust the system you are putting your life at the hands of. Long story short, this solves an imagined problem. When you consider why X doesn't have Y medical system. It's not because of the price of the kit. It's the entire system that is too expensive. If you can't afford a brand incubator you probably can't afford the it intense cleaning regime needed for the room to put that incubator in!

khazhoux 5mo ago
metanym (taxonomy) A name that is rejected because a valid name (based on another member) already exists for the same group.
- ButlerianJihad 5mo ago
  metonymy (rhetoric) The use of a single characteristic or part of an object, concept or phenomenon to identify the entire object, concept, phenomenon or a related object. https://en.wiktionary.org/wiki/metonymy#English https://en.wiktionary.org/wiki/metonymy#English
davikr 5mo ago
Yes, if you're going to be using it for the next 10 years, it is worth going for the more expensive Littman if you can. However, I've heard that there are decent Chinese clones, and honestly I've used those $1 stethoscopes in isolation units and they're not terrible for basic pulmonary auscultation.
- copperx 5mo ago
  But where do they fail? What does a good stethoscope bring? better and clearer amplification?
  - throwaway2037 5mo ago
    Yeah, that comment also sent off internal alarms for me also. It would be a great blog post (or YouTube video) for someone to buy a bunch of stethoscopes and objectively test them. I would bet that there is a 10 USD model that is 98% as good as 200 USD models from 3M Littmann. And similar to the neverending arguments about "premium high-fidelity stereo equipment", I bet most doctors cannot tell the difference between the two when the logo/brand is hidden. BTW: I found the 3M Littmann page on Amazon. The prices are wild: https://www.amazon.com/stores/3MLittmannStethoscopes/page/42802ABB-C5E1-4417-8239-4EB5412FA75E https://www.amazon.com/stores/3MLittmannStethoscopes/page/42...

f1shy 5mo ago

You can measure all the parameters you want. The question is: does it really matter? I know many doctors, and one of my favorite questions is about stethoscopes: I have unanimously the answer "I could just roll a piece of paper and if the room is quiet enough, I can do my work". My grandpa used one made out of wood, just a cone. Once, I was fascinated by a Littmann, with bluetooth audio, I told a friend doctor, that would be great (thinking about a present) the answer was "That is all hype, I can do with a $2 piece exactly the same". I pointed out the possibility to record the sound, to possibly defense in case of being sued: she laughed out loud, said is unpractical to record everything, would take too much time, and again, just a toy.

morkalork 5mo ago
Lots of nurses and EMTs swear by the amplified Bluetooth stethoscopes but unlike a Dr working in a nice quiet office, they're often in much noisier conditions.
- bombcar 5mo ago
  The difference between a $100 mic and one that costs ten to a hundred times as much is not how well they work in perfect conditions, but how well they work in the worst conditions imaginable. Doctors often have the seniority and authority to make the room quiet; nurses and EMTs are often working in much different conditions.
matheusmoreira 5mo ago
> I could just roll a piece of paper and if the room is quiet enough, I can do my work That is true. The job is certainly doable. It's also possible to press one's ear against the patient's body to directly listen to the sounds without any tools whatsoever. Stethoscope was itself invented because a male doctor doing that to a woman's chest was uncomfortable for obvious reasons. There is some kind of difference between a good littmann and a cheap stethoscope. My experience is that the important sounds are just easier to hear with the littmann. Would love to know why that is, and why the cheap ones just can't seem to match it.
dlcarrier 5mo ago

ZiiS 5mo ago

That label the graph "log dB" which seems a very odd choice if you wanted to show differences