Short version:
☝title, something that can be clipped onto scrubs or worn around the neck. Also easy to clean - hard surfaces that can be wiped down with alcohol, no cloth coverings or anything.
Long version:
Nursing student here. Basically I’m trying to build a stethoscope that doesn’t need to be inserted into my ears.
I have some hearing loss, and currently use hearing aids, which has posed a frequent annoyance / hazard at my clinical rotations when it comes time to listen to my patient’s heart and lung sounds. I can’t use a normal stethoscope with the hearing aids in, cuz it shoves them way too deep into my ear canal (doesn’t feel great); so I’ve just been popping the fuckers out and using the stethoscope normally when needed. …but I hate doing that, cuz hospitals are disgusting - there’s literal and metaphorical shit on everything, so screwing with the hearing aids mid shift is 100% introducing pathogens into my ears.
At my last clinical site, one of the nurses had a bluetooth stethoscope that seemed like the miracle solution I needed - it’s basically a stethoscope bell with no tubing, and it pairs with bluetooth headphones. She let me try it out, so I paired it with my hearing aids, and… heart beats sounded like two pieces of metal clanking against eachother. Total flop, clinically useless. Fuck.
So I whine to my audiologist, and eventually we figure out that the issue is that heart and lung sounds range from 20-100 hz; and my hearing aids are designed to amplify human speech, which is about 300-3000 hz. The speakers in my hearing aids are not physically capable of playing heart and lung sounds (that clanky metal sound was just the tiny bit that overlapped with the hearing aid’s range). More fuck.
So, I don’t think my hearing aids are going to be part of the solution here, but I’m still seeing potential in the bluetooth stethoscopes: but instead of pairing it with bluetooth headphones, since again the ear canals are already occupied, instead pair it with a bluetooth speaker that I can clip onto my scrubs or use the kind that hangs around the neck.
Poking around the internet, there are tons of those types of bluetooth speakers, but they never seem to advertise the hertz range and I’m worried about getting a whole setup built, then running into the same issue with the new speaker not playing the sounds I need to do an actual nursing assessment. And those bluetooth stethoscopes are expensive as fuck, so if I’m going to dive in to this, I want to make sure I don’t screw it up.
What do you all think? Any brands or specific products you’d lean to?
Also, bonus question: putting yourself in the patient’s shoes: how would you feel if your nurse dropped in rocking a setup like this? If it’s playing through normal speakers, YOU the patient would be able to hear your own heart and lung sounds during my assessment - my thought was it’d be great for patient education: “That clicking sound when you exhale is called crackles, which means there’s fluid in your lungs, so…” Would that make for a decent patient experience, or be offputting or intimidating? I’ve been a surgical tech for like a decade, so my perspective is pretty skewed in terms of how much info is too much info.’
Thanks all!
Tried bone conduction headphones yet?
https://www.techradar.com/news/best-bone-conduction-headphones
I actually have a pair of shokz - they’re awesome! I don’t think they’d work for this specifically though - they struggle with low ranges, and one of the Bluetooth stethoscope websites specifies that bone conduction isn’t a good match.
…worth a shot though - if it does work, it’d be a super convenient solution!
Seems to me you’d be better off with a circuit that up-converts 20 to 100 Hz sounds by a factor of 20, putting them into a range you can hear. That would not have to be a complicated circuit, and no doubt they’re already out there.
Or it could convert sounds in that range into something that amplifies those frequencies and vibrates against your skin instead (a ‘skin speaker’) … probably easier to make than a converter.
Rtings.com provides frequency response charts when they test speakers, let me see if I can find one that goes low enough for you.
As for the bonus question, absolutely love it. I love when people come up with cool solutions to life’s problems, and this lets me hear my own heartbeat? Hell yeah!
Here’s an easy way to check a bunch of them quicky, the Denon home was the best I found in terms of the very low end. I’m sure someone else can do better, I’m not that much of an audiophile and know very little about speakers.
Probably worth noting that they stretch out the low end of the chart so they tend to go lower than it seems (I assume it’s a logarithmic scale). You might be able to go to a store and ask to test them yourself.
Second edit: if headphones are at all a possibility (they might be better for patients who don’t want to hear their own heartbeat) then can I recommend Skullcandy crushers? They’re completely ridiculous as regular headphones, they basically just have a metal plate they vibrate for the bass, but it goes all the way down to 20Hz, and you can crank it waaaaay up with a slider on the side. (I use these daily for music because I’m a bad audiophile who wants to have fun sometimes, I have a proper wired setup if I want the audiophile experience.)
+1 the crushers. I’m not sure of anything else that currently exists that would get down to those low frequencies without being annoying or expensive
Thanks!!
Looking at those graphs, I’m assuming amplitude in that 20-100 hz range is ideally as close to that center line as possible? Seems like most options are very low on that range, but not completely absent - how low would you say is too low for a project like this?
Like that Denon in your second link, 20 hz is showing at about -17 on the amplitude axis, is that audible?
Skullcandy crushers
Definitely not going to rule out headphones, as those might be the best option; but my main hangup there is bulk, and needing to actually handle it with each use. Part of why I was leaning toward those hang-around-the-neck bluetooth speakers is the thin profile and that I can just leave them on and paired with the stethoscope - then the only thing I’d have to handle is the stethoscope itself. Minimizing actually touching it is definitely a priority… can’t stress enough how nasty hospitals are!
I’m afraid I can’t answer your technical questions, I’m really not that knowledgeable about this. All I know is you ideally want the frequency curve to be flat, I don’t think it matters much where it sits relative to that line.
Honestly, that Danon dropping off at the low end is pretty typical though it’s one of the better ones. You’d really just have to test it I’m afraid, it might be totally fine to chop off the bottom for some things but maybe it’s necessary for certain heart conditions, I wouldn’t know. If it were an option I’d say the best bet is to always stick to the analogue, but I’m absolutely with you on hating traditional stethoscopes, they’re so painful…
You probably can just leave the crushers on your neck with the volume maxed out, but I’m really not sure if that’ll work. In all honesty the speaker might be worse due to the way the acoustics in the room can change what you hear, it’s really hard to say.
Yes, you want to find a speaker with a flat sound signature.
This is a type of speaker called “studio monitor”.
Remember that sound is very unforgiving when working with it, every single step in the chain of recording a sound to playing it back can change how it sounds, with the changes to the sound being compounded when you play it back.
This includes the microphone, the microphone amplifier, the speaker amplifier and the speaker.
This does not mean that it is impossible to do what you want, but be prepared that the sound may sound strange from what a normal stethoscope would produce.
I dont know if they fit with your hearing aids, but maybe look into bone conducting headphones. I have Openrun Shokz Pro and they work pretty good with music. They have a waterproof version which is good for your hygiene needs.
Your Bluetooth speaker around the neck idea might be hard to achieve. The wavelength of a 100hz signal is around 3,5 meters and is getting bigger the lower you get. This means you need more energy and bigger drivers for true reproduction of low frequencies. A 100hz speaker might get heavy around the neck.
Sidenote: When I’m wearing my Shokz I sometimes get asked if I wear hearing aids.
I actually have a pair of shokz - they’re awesome! I don’t think they’d work for this specifically though - they struggle with low ranges, and one of the Bluetooth stethoscope websites specifies that bone conduction isn’t a good match.
…might be worth a shot though - sounds quality doesn’t need to be amazing, it just needs to be audible.
Give em a shot. They should work if you pitch-shift them with some simple software to make the 20hz sound like 50hz or whatever.
pitch-shift them with some simple software to make the 20hz sound like 50hz or whatever
Ooh. OOH! Okay so I’m kind of an idiot when it comes to tech, but that sounds like a high-potential option. How would I go about doing that?
Thousand way to do it, like this: https://play.google.com/store/apps/details?id=com.stonekick.tempo
But most platforms have decent DJ or audio software for this.
I’ll need to dig into this a bit. If I’m going to use my phone as a bridge between the stethoscope and hearing aids, I’ll need something that can boost the pitch in real time. I don’t want any patient data saved onto my phone. Some of the Bluetooth stethoscopes have a corresponding app that can save sound clips, but that strikes me as risky from a HIPAA standpoint.
Anywho, DJ software didn’t even cross my mind, so thanks! Awesome idea!
Sounds like you want small guitar or DJ hardware like: LEKATO Mini Pitch Shifter Pedal to try out the concept. If you have a musician shop in your area, try their selection.
I’m not a medical professional nor do I use hearing aids, so I might be misinterpreting the situation here, but are the speakers actually the problem? Presumably the other nurse’s headphones were capable of playing the sounds in that range; the problem was your hearing aid. How does having another speaker playing those same sounds help, if your hearing aid still isn’t able to correctly handle them?
It seems like what you’d actually need is something that can take in the sounds in the 20-100 hz range, but play them back in the 100-3000 hz range, so your hearing aid can pick them up, no?
Not OP, but I also suffer from hearing loss and wear hearing aids. Hearing loss in most people is not linear and certain frequencies are more compromised than others. This shows up as dips in an audiogram report. For me, I can hear low frequencies just fine. In fact, I can make out most words spoken by my male coworkers even without my hearing aids, due to their speech falling below the range of my hearing loss. I have a much harder time hearing females because their vocal range is higher in frequency so it comes through as very muddy. My hearing aids have open domes that pass sound, so they don’t act like earplugs for the frequencies they’re not amplifying.
My hearing aids also have the ability to pair with my phone and play music, but I never use it because they sound godawful because the drivers are miniscule. Fine for reproducing the mid and high frequencies required to boost audio in my hearing loss, but physically incapable of producing anything below probably 2-300 hz.
Everyone is obviously different, so not saying OP has the same situation as me, but based on their description of the problem and discounting the hearing aids as part of the solution, we’re probably fairly similar.
^that.
I can hear low ranges pretty well, to include heart and lung sounds from a normal stethoscope.
Using speakers or headphones that can play that 20-100 hz range would effectively bypass the hearing aids - they wouldn’t record or payback those sounds at all, it’d just be a straight shot from the Bluetooth speaker to my ears.
Not suggesting that what I’m about to describe is a common reaction but I’d be a little uncomfortable with the privacy implications of the setup. Is there a light to show it’s on? How about a physical switch to completely interrupt the mic’s connection when it should be off? Don’t need a bored nerd down the hall with a Flipper tuning in for some free entertainment in the form of my colonoscopy results.
Here’s the one I’m looking at - Stemoscope Pro (lol can you tell the pandemic was in full swing when this vid hit?!)
There’s a microphone, but not in the sense that you’re probably thinking - it can’t pick up conversations and such the way a phone or something could. For it to work it has to be pressed up against tissue for that sound to conduct through to it. It’ll still pick up some ambient noise, but nothing intelligible.
Basically the same with a normal stethoscope - the bell is always transmitting sound to the ear pieces, but you can’t like put the ear piece in and use it to spy on someone the next room over - gotta shove it onto their skin for anything with any degree of clarity to come through.
So, it’s not capable of storing your colonoscopy results. Paired with a phone, it could save a recording of your bowel sounds if it was used to listen for those, but even that isn’t something that could be used to identify you. Everyone’s bowels makes pretty much the same gurgle - your nurse is just checking to make sure they’re present and whether the frequency of them is normal.
All that said, I don’t like that there’s a phone app. The sounds themselves being saved is fine; but if some dumbass nurse saves that file as “John Smith.mp3” then that’s 100% a HIPAA violation. That kind of app should only ever be used on hospital-owned devices, never personal ones. Needless to say, I don’t intend to ever install the app - fuck that liability, even if it comes down to a baseless accusation. I’ll just pair it directly to a speaker, play the sounds in real time, and that’s it. If I need to listen to them again, I’ll need to take them again.
The hypothetical version of me that is your patient has been mostly reassured by that response. I just don’t want to be paying for any potential eavesdroppers’ therapy bills on top of my own. Realistically, I know that nobody cares what’s going on in the exam room with me unless they’re involved. Think most of the lingering concerns would be addressed by whatever I can hear (and for that matter, what I can’t) being picked up by the system and sent to speakers as well.
Also, once you get the frequency range thing hammered out, your patients can show you where it hz. Bad joke aside, this has me wondering whether there’s anything that would be improved by applying some basic filters so you could focus on one range of frequencies, maybe even apply a pitch shift to move those sounds into a range your hearing aids can handle better.
Here’s why I’ll never be allowed to make medical devices: my next idea would be to hide autotune and a few guitar/bass pedal effect filters in the code so you could live out some rock and roll fantasies on the job. Air guitar takes on a whole new meaning when you’re playing along with respiratory noises.
Thanks for the detailed reply, hope you find nursing to be the right combination of engaging, challenging and rewarding to enjoy the career.
your patients can show you where it hz.
Air guitar takes on a whole new meaning
I’m imagining the overhead page system going off with “ATTENTION I’M THE HOSPITAL! CODE SAXOPHONE! ROOM 338! ALL TEAMS RESPOND!”
You might be on to something though - alarm fatigue is a huge issue in healthcare, so coding familiar sounds like instruments as meaning specific things could actually be great. You hear a saxophone tone and know immediately that something cardiac is happening; guitar, respiratory, etc.
Right now everything is just a beep, and after hearing that non-stop for years, you kinda just stop noticing it, which is super bad.
I haven’t any idea how they’d work with your hearing, but what about bone conduction headphones? They can be wiped down easily and are often waterproof.
I got the Sony SRS-XB10 specifically because it has a range as low as 20hz… not sure if there are newer ones out that are better now
Double check that the problem isn’t actually your hearing aid’s Bluetooth codec support, rather than the physical driver’s supported frequency range.
Bluetooth audio devices need to agree on an audio compression format before they can send audio, and the default lowest common denominator codec that all audio devices support is extremely bad at low frequencies (and is all around terrible). It could be that your hearing aid is good enough but doesn’t support whatever high-fidelity codec your coworker’s stethoscope supported. Investigate what codecs your hearing aid supports and what the stethoscope supports. You’ll probably want something like LDAC, LC3 (aka LE audio), aptx HD, aptx adaptive, or preferably even aptx lossless, to be supported on both devices.
If you’re considering investing a lot of money anyways, you may want to consider replacing your hearing aids with ones that support this functionality (the frequency response and the codecs).
As someone else already pointed out, if your current hearing aids don’t support below 100hz, then even if you play the sound over a speaker, your existing hearing aids are just going to act as earplugs. You may need to invest in different hearing aids or just live with taking out your hearing aids for the foreseeable future. Or I suppose just blasting the heartbeat over the speaker to bypass your hearing aid (caution wrt audio feedback lol)
