Frequently Asked Questions About Littmann Stethoscopes

General Stethoscope Questions

  • I can't hear anything out of my stethoscope. Is something wrong with it?
    If the acoustic performance seems to be lacking or absent, visit the Optimizing Performance page for tips to optimize your stethoscope's performance.
  • No. Littmann stethoscopes use Next Generation Tubing that does not contain natural rubber latex or phthalate plasticizers.
  • No. All of our stethoscopes contain metal.
  • The tunable diaphragm is a 3M invention that allows you to listen to both low and high frequency sounds without the need to remove the chestpiece from the patient, turn it over, and reposition it.

    By varying the pressure placed on the patient, a tunable diaphragm will adjust, or tune, the sounds to allow you to hear either low or high frequencies. When holding the tunable diaphragm on a patient and pressing lightly, low frequency sounds will be transmitted. When using the tunable diaphragm and pressing firmly, higher frequency sounds will be emphasized.

    This convenience will save you time and allow you to focus on your patient instead of trying to determine if you should be listening to the bell or diaphragm side of the chestpiece.

Cleaning and Care of Littmann Stethoscopes

Littmann Stethoscope Product Information

Electronic Stethoscopes

  • What are the advantages of an electronic stethoscope?
    Many heart and lung sounds that are difficult to hear for a variety of reasons can be potentially missed even with normal hearing. Amplification along with ambient noise reduction helps you hear the sounds you need to hear.
  • 3M™ Littmann® Electronic Stethoscope Model 3100 and Model 3200 cancel out, on average, 85% of ambient background noise that can interfere with the auscultation experience, without eliminating critical body sounds. So you're much less likely to miss the sounds you need to hear in noisy work environments; a full 13% better than previous models.
  • Littmann model 3100 and model 3200 stethoscopes were designed to accommodate three battery types to fit your needs. Use one AA alkaline, lithium, or NiMH battery to operate your electronic stethoscope. The default battery type is alkaline. Therefore, if using either a Lithium or NiMH battery, you must change the battery type within the setup menu of the electronic stethoscope for a reliable battery life indication on the display screen. The lithium battery is a non-rechargeable cell that is recommended for low-temperature operation of the stethoscope and generally has a longer life than an alkaline battery. The NIMH battery is a rechargeable battery (external charger required).
  • No. The electronic stethoscopes will not work without the battery.
  • First, it’s very important to wear the stethoscope properly. All Littmann stethoscopes have headsets that are angled and are designed to fit properly with your ear canals. Here’s the correct orientation: Hold the stethoscope with the eartubes vertical. When placing the eartips in your ears, be sure that the angled eartubes are pointing forward, toward your nose.

    Once the stethoscope is correctly oriented, adjust the sound amplification by pressing the "+" and "-" buttons on the keypad. Make sure that the very center of the chestpiece is making good contact with the patient; this is the location of the sound sensor. If you still cannot hear any sound, contact 3M Technical Support at 1-800-228-3957 or use the Contact Us form

  • When using the 3M™ Littmann® Electronic Stethoscope Model 3100 and Model 3200, there are several techniques that are important to consider that can substantially improve your auscultation experience.

    The sound sensor, where all sound acquisition occurs, is quite small and located in the very center of the chestpiece (for demonstration purposes, you can peel off the diaphragm and look for the indentation under the white sticker). The area around the sound sensor does not contribute to sound acquisition. Therefore, it is important to focus the point of contact with the patient on the very center of the chestpiece.

    Only light contact is necessary with the Littmann electronic stethoscopes. This includes both the handling of the stethoscope and the contact on the patient. Excessive pressure on the patient may result in artifact sounds.

    Contact with the patient must remain steady and consistent for optimal sound quality. Movement with the chestpiece will induce frictional noise. It is a best practice to start your auscultation exam at a lower amplification level. Then, if you are trying to listen to a difficult to hear sound, adjust the amplification upward. Using the amplification on an as needed basis will help reduce distracting noises during your exam.

    Finally, it is important to recognize the difference in technique between non-electronic stethoscopes and the Littmann electronic stethoscopes. Holding the Littmann electronic stethoscopes lightly, making light contact with the patient, focusing the point of contact on the center of the chestpiece, and remaining steady will assure the highest sound quality auscultation experience.

  • A Littmann model 3100 or model 3200 stethoscope battery will last for approximately 60 hours of continuous use. (Depending on Bluetooth® usage, you may experience a shorter battery life with model 3200.) Before the battery is depleted completely, you will hear a warning tone that the battery has only two more hours of continuous use. The life of the battery is being conserved if you are seeing the Littmann® logo; you are in standby mode. To enter active mode, tap on the diaphragm or push a button. To turn off the stethoscope, either do nothing (the stethoscope will power off after a period of time that is based on the POWER setting) or push the power button for two seconds (preferred).

    There are several options to maximize battery life:

    1. Minimizing backlight display time will conserve battery life. Select Menu > BACKLITE and then select either DISABLE or ON DMND (on demand). DISABLE will completely disable the backlight at all times. With ON DMND, the backlight will only activate after pressing the power button. If you feel the backlight is necessary in order to read the display screen, simply select Menu > BACKLITE > ALWAYS. This will activate the backlight at half power to provide visual assistance, yet minimize power consumption.

    2. Ensuring that the Auto On / Auto Off feature is enabled (should be by default) will preserve battery life. This feature can be customized to allow for different periods of time before entering standby mode. To optimize the battery life, select Menu > POWER > LOW. This will program the stethoscope to enter standby after 10 seconds of inactivity.

    Sound quality remains constant even on low battery. The electronic stethoscope will not work without a battery.

  • Bluetooth® wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
  • No. A USB Bluetooth® adapter (dongle) is included with the purchase of the Littmann model 3200 stethoscope. Simply connect the Bluetooth dongle to your PC using the USB port and your computer will become Bluetooth enabled. For optimum performance, it is recommended that you use the wireless dongle included with the Littmann model 3200 stethoscope.
  • The Littmann model 3200 stethoscope uses a Class 2 Bluetooth link, with a maximum range of 10 meters (about 30 feet). The Bluetooth range will be reduced when objects (walls, furniture, people, etc.) are in-between the Littmann model 3200 stethoscope and the PC. To improve Bluetooth communication, reduce the distance and/or allow a line of sight between the Littmann Model 3200 stethoscope and the external device.
  • How can I optimize Bluetooth® wireless performance?

    For optimum wireless connection performance, it is important that the stethoscope chest piece and wireless dongle are in close proximity and that the path between them is free of any obstructions. Walls, furniture, and bodies will degrade the wireless signal.

    The positioning of the stethoscope and wireless adapter is crucial to good wireless performance. In some cases, the use of a USB extension cable which elevates the adapter and/or changes its orientation can result in a marked improvement. 3M recommends using the StarTech Desktop USB Extension Cable, or similar device, that can be found online at many retailers or at your local electronics store.

    During recording, it may help for the PC to be located next to the patient (rather than behind them) so that the patient's body does not block the signal path. Hold the chest piece firmly with fingertips (rather than a cupped hand) to allow the wireless antenna to function optimally. Minimize the distance between stethoscope and PC. Under typical conditions, a distance of 10 feet should be readily achievable.

    Operating environment also plays a role in connection performance. Cordless phones, cellular phone accessories, microwave ovens, and computer Wi-Fi equipment may all degrade connection performance and should be considered if connection performance is less than desirable.

  • Many scientific Bluetooth coexistence studies performed by 3M and other institutions and have shown that Bluetooth does not interfere with other wireless devices/technologies. In addition, Bluetooth is strongly supported by Continua (SIG group for Telemedicine) and a new Bluetooth Health Device Profile (plug-and-play BT communication protocol for medical apps) was just recently established and the first compliant products are now available. Further, devices with similar technology to ours have been approved in other critical-care settings, including OR suites and ICU floors.
  • No. The Littmann model 3200 electronic stethoscope is not compatible with any Bluetooth hearing aid devices.
  • By default, the sound will be played directly back to the Littmann model 3200 stethoscope via Bluetooth. Listening to previously recorded sounds using the Littmann model 3200 stethoscope is recommended, as the sound quality will be identical to what you heard while recording. If the connection icon is green (on StethAssist™ or Cardioscan®), try increasing the audio volume by pressing the "+" on the stethoscope.

    If the "play to PC" checkbox is checked, then the sound will be played via the PC speakers instead of the stethoscope. Because of the low frequency sounds involved in auscultation, computer speakers (especially native laptop speakers) may have very poor audio response giving the impression that sounds are not playing. If "play to PC" is selected, the use of headphones typically works well. Desktop speakers will allow you to hear the recording, but will typically distort the low frequency sounds. The best alternative for playing the recorded sounds to an audience is to use a speaker system with midlevel speakers and a subwoofer.

  • The sound files are transferred via Bluetooth® communication. Bluetooth is a secure method of file transfer. Files transferred via Bluetooth are encrypted and can only be read by the PC that is connected to the Littmann model 3200 electronic stethoscope.
  • Before you can transfer data between two Bluetooth® devices, they must first be "paired" electronically. Pairing is a discovery and authentication process that allows your Bluetooth-equipped Littmann model 3200 stethoscope to communicate with another Bluetooth-equipped device, and establishes the link between these two devices as a trusted pair. While StethAssist can remember trusted pairing with up to eight different Bluetooth devices, it will only communicate with one paired device at a time. In addition, you cannot pair two Littmann model 3200 stethoscopes together.

    Once paired, the Littmann model 3200 stethoscope can connect to the PC running StethAssist. Select the CONNECT option by pressing and releasing the (M) button. The LCD screen will signal that the Bluetooth link is active. The stethoscope will automatically return to operational status.

  • Littmann recommends cleaning the stethoscope in-between every patient with a 70% isopropyl alcohol solution or wipe. Do not immerse your stethoscope in any liquid or subject it to any sterilization process. For more information on cleaning both electronic and mechanical stethoscopes, see Cleaning and Care.
  • Go to to download and install the latest version of the StethAssist software, now compatible with Macintosh computers.
  • StethAssist™ is software used with the 3M™ Littmann® Electronic Stethoscope Model 3200 for the recording and display of heart sounds and other physiological acoustic signals. StethAssist software works with the Littmann model 3200 stethoscope, and runs on a PC meeting the specified requirements.
  • The 3M™ Littmann® Electronic Stethoscope Model 3100 and Model 3200 have been subjected to splash tests, drop tests, cleaning tests, button-press tests and other rigorous testing to ensure that they can withstand the toughest conditions. The solid, cast-metal construction and durable chrome finish of the chestpiece can stand up to years of wear and tear. The Littmann model 3100 and model 3200 stethoscopes are validated to operate at -22°F to 104°F (-30°C to 40°C) and a relative humidity range of 15 - 93%.
  • Every time I turn on the stethoscope, I have to change the amplification. Can I set a different default amplification level?
    Yes. Select the amplification level you would like to set as default. Press the M button, then press the "-" button until SET VOL is selected, and then press the M button again. The default amplification has now been changed to the new level and is indicated by a small mark in the vertical line next to the volume bars.
  • Yes. Select the filter type you would like to set as default. Press the M button, then press the "-" button until SET FLTR is selected, and then press the M button again. The default filter type has now been changed to the new selection.
  • The Littmann model 3100 and model 3200 stethoscopes were designed to auscultate people of all sizes, including infants and small children. The acoustic sensor is 15mm in diameter, about the size of a small button or dime, and is located in center of the chestpiece. Therefore, when auscultating a patient, you only need to be concerned about making contact with the very center of the chestpiece to achieve optimal sound quality.
  • When trying to obtain the heart rate of a patient, it is important that the very center of the chestpiece is making good contact with the patient, as this is the location of the sound sensor. It takes five seconds of consistent heart sounds to compute the initial heart rate and updates are provided every two seconds. The heart rate will then be displayed for 10 seconds after removal of the chestpiece from the patient. Prior to the initial reading, the display shows two dashes (--).For heart rates outside a range of 30-199 bpm, the display will also show two dashes (--).

    The acoustic-based heart rate display functions best when the Littmann model 3100 or model 3200 stethoscope is placed near the apex of the patient’s heart. It can be monitored while using any filter mode or volume level. If the heart rate changes from consistent to inconsistent, or if there is excessive ambient noise, patient movement, or lung sounds during auscultation, the heart rate will display two dashes (--). With practice, your ability to obtain a heart rate from your patient will improve. The heart rate feature was designed and validated for us on humans.

  • While 3M does not provide engraving services, several Littmann stethoscope retailers will engrave your stethoscope. Please consult our retailers directly.
  • You can obtain pricing information from any Littmann stethoscope retailer. Pricing may vary between retailers. Check the Where to Buy section to find a retailer near you.
  • We offer complete Littmann stethoscope repair and service to ensure your equipment can keep up with your day-to-day workload. Do not attempt to repair the electronic stethoscope yourself. Notify the 3M Health Care Service Center at 1-800-228-3957 or use the Contact Us form.
  • Two-year eartip-to-diaphragm warranty.
  • No. Unfortunately, these electronic stethoscope models are no longer repaired by 3M due to the unavailability of parts.

3M™ Littmann® TeleSteth™ System