Quantifying a Headphone’s “Feel” with Force Measurement

Background:

A manufacturer of headphones required a quantifiable method of describing the feeling of the earpad cushions against a consumer’s ears, and gauging the ability of headphones to fit snugly over a period of time. It was determined that simply asking people to wear the headphones and comment on its comfort was too subjective. The manufacturer also wanted to compare their products with those of their competitors.

It was determined that force measurement was an ideal method by which to quantify the differences in “feel” from one set of headphones to another.

How Mark-10 Helped:

The manufacturer turned to Mark-10’s distributor in Taiwan ROC, Jye Cheng Crown Trading Company. Jye Cheng recommended and supplied a Mark-10 force testing system to pull the earpads apart, and monitor the relationship between force, time, and distance. Our distributor locally fabricated custom fixtures to engage the manufacturer’s earpads, as well as their competitors’.

In conjunction with Mark-10 and our distributor, the manufacturer developed and uses following testing methods:

Pull to a target force and note the corresponding change in distance.
Measure force vs. distance vs. time to a target distance.
Cycle the headphones to a distance limit thousands of times, and note any trends in peak amplitudes. A decline in peak values can indicate material fatigue, possibly requiring a reassessment of the product design.
Determine sample relaxation by cycling to distance limits, pausing for pre-determined dwell times, and noting drops in force during these intervals. Substantial drops can point to material or geometry deficiencies in the headband assembly.
Pull to a target load and maintain the load for a period of time. The test stand automatically adjusts the crosshead position if the sample relaxes, thereby maintaining the force. Drops in distance can similarly indicate an issue with the material or product design

Gallery:

Products used:

Model ESM303H motorized test stand
Model M5I force/torque indicator
Series R03 force sensor
MESURgauge Plus data collection software
Custom fixtures