Whether you are a medical professional or a patient, you have probably heard of stethoscopes. But do you know the difference between an open bell and a closed bell stethoscope?

What is a bell in a stethoscope?

The bell is the small, cup-shaped piece at the end of the stethoscope. It amplifies sounds so that the user can hear them more clearly.

There are 2 types of bell designs – open and closed and their key difference lies in their design.

Summary of Open vs Closed Bell Stethoscopes:

An open bell stethoscope has a diaphragm that covers the entire surface of the bell. This design amplifies high-frequency sounds, making it ideal for listening to heart and lung sounds.

The open bell model is most effective in detecting lower pitch sounds, such as some heart murmurs and bowel sounds. It also can be used to detect bruits and for heart sound exams (when listening with the diaphragm, be sure to repeat with the bell).

A closed bell stethoscope has a small diaphragm that covers only part of the bell. This design amplifies both high- and low-frequency sounds, making it ideal for listening to both heart and lung sounds.

The closed bell model is most effective in detecting higher pitch sounds, such as some heart murmurs and bowel sounds. It also can be used to detect bruits and for heart sound exams (when listening with the diaphragm, be sure to repeat with the bell).

So, which type of stethoscope is right for you?

If you are looking for a versatile model that can be used for both heart and lung sounds, then a closed bell stethoscope is the way to go. If you are mainly interested in heart sounds, then an open bell stethoscope is a good choice. Whichever type you choose, be sure to get a high-quality model from a reputable manufacturer.

8 Key differences: Closed vs Open bell stethoscope:

1. Open bell stethoscopes have a diaphragm that covers the entire surface of the bell while closed bell stethoscopes have a small diaphragm that covers only part of the bell. For open bell stethoscopes, this design amplifies high-frequency sounds while for closed bell stethoscopes, this design amplifies low-frequency sounds.

2. Open bell stethoscopes are ideal for listening to heart and lung sounds while closed bell stethoscopes are ideal for listening to blood pressure and bowel sounds. It all has to do with the design of the diaphragm.

3. You can buy open bell stethoscopes that come with a second, smaller diaphragm that can be used for low-frequency sounds. This is not possible with closed bell stethoscopes.

4. Open bell stethoscopes are generally more expensive than closed bell stethoscopes.

5. Open bell stethoscopes are less likely to cause skin irritation than closed bell stethoscopes. This is because the diaphragm of an open bell stethoscope covers a larger surface area, making it less likely to come into contact with the skin.

6. Open bell stethoscopes are more likely to pick up ambient noise than closed bell stethoscopes. This is because the diaphragm of an open bell stethoscope is more sensitive to sound waves.

7. Open bell stethoscopes are more likely to get damaged than closed bell stethoscopes. This is because the diaphragm of an open bell stethoscope is more exposed and thus more vulnerable to being ripped or torn.

8. Open bell stethoscopes are less likely to transmit infection than closed bell stethoscopes. This is because the diaphragm of an open bell stethoscope is less likely to come into contact with the skin.

When using a double-sided Littmann stethoscope, you must open (or index) the side you want to use—bell or diaphragm—by rotating the chestpiece. If the diaphragm is open, the bell will be closed, preventing sound from coming in through the bell, and vice versa. This is not an issue with other brands of stethoscopes.

No matter what type of stethoscope you use, it is important to clean it after each use to prevent the spread of infection. You should also inspect your stethoscope regularly for signs of wear and tear. If you notice any damage, replace your stethoscope immediately.