The ST-504 instruction for use lists the noise level as **less than 80 dBA measured at 30 cm**. This is a product specification under the stated test condition. It is not a promise that every user will perceive the devic
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Practical meaning
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The ST-504 instruction for use lists the noise level as less than 80 dBA measured at 30 cm. This is a product specification under the stated test condition. It is not a promise that every user will perceive the device as quiet in every room.
How to interpret the number
dBA is an A-weighted sound-level measurement. The 30 cm distance matters: sound changes with distance, room reflections, furniture, and background noise. A reading taken beside the controller should not be compared directly with a reading taken across a room.
The pump, air movement, sleeve fit, and surface beneath the controller can also change the perceived sound. The specification gives a reference point for comparison; it does not describe the tone, vibration, or comfort of every session.
Practical setup
Place the controller on a stable surface. Keep the tubing free from sharp bends. Keep the controller within reach. Do not cover it or alter the device to reduce sound. If the noise changes or becomes harsh, stop. Use the ST-504 troubleshooting guide if an error or abnormal operation also appears.
What the specification does not establish
Noise level does not establish treatment effectiveness, medical suitability, or safety for a diagnosed condition. Read the ST-504 complete guide for operating context and the safety and contraindications guide before use.
Source
The less-than-80-dBA figure and 30 cm test distance come from the ST-504 instruction for use. Broader medical-device context is available from FDA medical device information.
