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The Ultimate Acoustic Stethoscope Review (page 5)

Stethoscope Frequency Response (Human Heart Power Spectra):
    Human heart power spectra were recorded from the diaphragm using both stethoscope earpieces attached to the microphone of our sound pressure meter. The control was the microphone pressed directly against the chest wall. The sounds were analyzed for sound pressure level in decibels as a function of frequency from 20 Hz to 20,000 Hz. All spectra shown below were recorded on the same patient (volunteer 1). The results show that most stethoscopes amplify sounds below 100 Hz and attenuate sounds above 200 Hz.

Model	Cardiac Frequency Response (Power Spectra)
ADC Platinum Cardiology 615
ADC Adscope Professional 603
AllHeart Cardiology
DRG Puretone Traditional PT3
Single Head Nursing Stethoscope
Littmann Cardiology I
Littmann Cardiology III
Littmann Master Classic II
Littmann Classic II SE
Omron Sprague Rappaport
Prestige Sprague Rappaport Stealth
Welch Allyn Tycos Elite

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Stethoscope Review: Contents

• Page 1 Introduction
• Page 2 Dimensions and Build Quality
• Page 3 Subjective Clinical Testing
• Page 4 Objective Clinical Testing
• Page 5 Human Heart Power Spectra
• Page 6 Tunable Diaphragm Effect
• Page 7 Conclusions and Recommendations
• Page 8 Feedback and Comments

Free Auscultation Resources

• The Auscultation Assistant (Listen to normal and pathological heart sounds)
• Phonocardiography Software (Thinklabs version of the Audacity sound analysis program)
• Limitations Of The Ultrasound Stethoscope
• Echocardiography Journal

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