The frequency response curve is the most important figure on a balanced armature receiver datasheet. It tells you how loud the receiver is at every frequency, which determines whether it can hit your target sound. Here is how to read one without an acoustics degree.
What the two axes mean
The horizontal axis is frequency, from bass on the left to treble on the right, usually 100 Hz to 20 kHz on a log scale. The vertical axis is output level in dB SPL - how loud the receiver plays at each frequency at a fixed drive voltage. A curve that sits higher means a louder receiver overall.
Sensitivity: where the curve sits
The overall height of the curve is the sensitivity. Two receivers can have similar-shaped curves at very different heights; the higher one needs less voltage to reach the same listening level. When you compare models for the same application, compare curves at the same drive conditions and coupler.
Shape: what flatness tells you
The shape tells you the tonal balance. A flatter curve means more neutral sound. Peaks and dips show resonances or response features you will need to correct with acoustic damping or crossover design. The datasheets in our Download Center include the typical frequency response for every model, so you can compare shapes before ordering samples.
Limits: where the curve stops being useful
At the low end, the curve rolls off as the receiver runs out of output. At the high end, the useful range ends where the response collapses. When you plan a multi-driver design, you assign each receiver to the band where its curve is well behaved, not where it is rolling off.
Use the curve with the spec table
The curve works together with the specification table: impedance, sensitivity at 1 kHz and maximum output. Check the curve for shape, the table for numbers, and the application pages such as hearing aid receivers or TWS receivers for which models fit which use case. Then validate with samples - the curve is the starting point, your enclosure is the final judge.