Skip to Primary Navigation Skip to Site Navigation Skip to Main Content All 3M.com Site Map

Tunable Technology


3M™ Littmann® Stethoscopes Tunable Technology
Tunable technology provides convenience, versatility and enhanced acoustics. The dual frequency diaphragm combines both bell (low-frequency) and diaphragm (high frequency) into a single side of the chestpiece. You control bell and diaphragm modes by pressure on the chestpiece rather than by turning it over.

Click on the buttons below for a demonstration



Light Contact

Firm Contact


Bell Mode (low-frequency)
For low-frequency sounds, light contact is used on the chestpiece. The diaphragm membrane is contained by a flexible surround that actually suspends it, allowing the membrane to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)
For high-frequency sounds, firm contact pressure is used on the chestpiece. By pressing on the chestpiece, the diaphragm membrane moves inward until it reaches an internal ring. The ring simply restricts the diaphragm membrane's movement. It blocks, or attenuates, low-frequency sound and allows you to hear the higher frequency sounds.


No other stethoscope gives you the same quality and efficiency in auscultation. How? Because 3M has the tunable diaphragm technology which allows you to alternate between low and high-frequency sounds without removing the chestpiece.

See Tunable Technology in action in these 3M™ Littmann® Stethoscopes: 

3M™ Littmann® Master Cardiology
3M™ Littmann® Cardiology III
3M™ Littmann® Master Classic II
3M™ Littmann® Classic II S.E.
3M™ Littmann® Cardiology S.T.C.
3M™ Littmann® Select
3M™ Littmann® Lightweight II S.E.