Stemoscope devices are just audio input devices like microphones. The audio quality is mainly determined by the output devices such as earphones/headphones. Obviously, earphones costing $200 can be very different from those costing $20. It is critical for you to have a good output device that can output auscultation sounds.
Earphones with balanced output are preferred, so that you can hear both low and mid frequency sounds. Most auscultation sounds are composed of low-frequency components. Some low-end earphones might not output bass sounds (low frequency sounds or low pitch sounds) well. However, earphones outputs too much low frequency sounds might make the auscultation sounds less crisp.
If you don't mind earphone size, headphone that can cover ears is recommended because it normally has a high output power.
For Bluetooth earphones, we recommend Apple AirPods Pro 2. Stemoscope PRO and AirPods Pro 2 work together perfectly (https://stemoscope.com/blogs/stemopedia/stemoscope-pro-digital-stethoscope-airpods-pro-2).
If you look for a turn key solution, you can try our own Bluetooth earphones, but please don't expect they are as good as AirPods Pro. While for general wired earphones, the original earphones coming with the iPhones or Samsung phones also perform well.
Please listen to the sample recordings to test the performance of your output devices. Please note that our ears are less sensitive to auscultation sounds because their frequencies/pitches/tones are low, so you need to increase the phone volume than normal when you listen to the sounds. If not loud enough, please increase the phone volume till the maximum is reached. Please note that when an Apple AirPods Pro is used to listen to Recording #1, the loudness is close to a traditional stethoscope for people with average hearing.
Recording #1 heartbeat sounds with default recording settings
Recording #2 heartbeat sounds with maximum volume boost