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Tunable Technology


A 3M™ Littmann® innovation


You’ve earned the right to wear the best. 3M™ Littmann® Stethoscopes are renowned worldwide for unsurpassed quality, performance and innovative design. One of the innovations that makes Littmann stethoscopes unique is our tunable technology.

How Tunable Technology Works
Our tunable, or dual-frequency, stethoscope diaphragms combine the bell (for low frequencies) and the diaphragm (for high frequencies) into a single side of the chestpiece. Move between bell and diaphragm modes by simply varying the pressure applied to the patient—there’s no need to turn the chestpiece over.

Using Bell Mode (for low frequencies)
For low-frequency sounds, rest the chestpiece lightly on the patient. When the diaphragm membrane is suspended, the membrane resonates low-frequency sounds.

Using Diaphragm Mode (for high frequencies)
For high-frequency sounds, use firm contact pressure on the chestpiece. By pressing on the chestpiece, the movement of the diaphragm membrane is restricted. This blocks (or attenuates) low-frequency sounds and allows you to hear higher frequency sounds.

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

littmann header

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

Littmann stehoscope's tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes on the 3M Littmann Master Cardiology Stethoscope requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure on the chestpiece to hear low-frequency sounds.

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Master Cardiology™ 3M™ Littmann® Master Cardiology™ 3M™ Littmann® Master Cardiology™

Master Cardiology Stethoscope

Tunable Diaphragm Technology

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

The 3M™ Littmann® Cardiology III stehoscope is equipped with tunable diaphragms on both sides of the chestpiece. The tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure on the chestpiece to hear low-frequency sounds.

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Cardiology III™ 3M™ Littmann® Cardiology III™ 3M™ Littmann® Cardiology III™

Cardiology III Stethoscope

Tunable Two-Sided

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

Littmann stehoscope's tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes on the 3M™ Littmann® Master Classic II Stethoscope requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure on the chestpiece to hear low-frequency sounds.

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Master Classic II™ 3M™ Littmann® Master Classic II™ 3M™ Littmann® Master Classic II™

Master Classic II Stethoscope

Tunable Diaphragm Technology

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

Littmann stehoscope's tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes on the 3M™ Littmann® Classic II S.E. Stethoscope requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure to either the open bell or tunable diaphragm to hear low-frequency sounds. (This animation shows the tunable option)

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Classic II S.E. 3M™ Littmann® Classic II S.E. 3M™ Littmann® Classic II S.E.

Classic II S.E. Stethoscope

Tunable Diaphragm Technology
or Traditional

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

Littmann stehoscope's tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes on the 3M™ Littmann® Cardiology S.T.C. Stethoscope requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure on the chestpiece to hear low-frequency sounds.

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Cardiology S.T.C. 3M™ Littmann® Cardiology S.T.C. 3M™ Littmann® Cardiology S.T.C.

Cardiology STC Stethoscope

Tunable Diaphragm Technology

The Convenience of 3M Littmann Stethoscope's Tunable Diaphragm Technology

Littmann stehoscope's tunable diaphragm technology offers enhanced acoustics, versatility and timesaving convenience.

Switching between bell and diaphragm modes on the 3M™ Littmann® Select Stethoscope requires a simple pressure change on the chestpiece. You no longer need to remove, index and replace the chestpiece for the same site auscultation.

Bell Mode (low frequency)

How to use:

Apply light pressure on the chestpiece to hear low-frequency sounds.

How it works:

A flexible surround suspends the diaphragm, allowing the diaphragm to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

How to use:

Without turning the chestpiece over, apply firm pressure to hear high-frequency sounds.

How it works:

Firm pressure on the chestpiece moves the diaphragm inward into contact with an internal ring. This ring restricts the diaphragm's movement, and blocks, or attenuates, low-frequency sounds allowing you to hear high-frequency sounds.

3M™ Littmann® Select 3M™ Littmann® Select 3M™ Littmann® Select

Select Stethoscope

Tunable Diaphragm Technology
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