The third-generation iPod had a weak bass response, as shown in audio tests. The combination of the undersized DC-blocking capacitors and the typical low-impedance of most consumer headphones form a high-pass filter, which attenuates the low-frequency bass output. Similar capacitors were used in the fourth-generation iPods. The problem is reduced when using high-impedance headphones and is completely masked when driving high-impedance (line level) loads, such as an external headphone amplifier. The first-generation iPod Shuffle uses a dual-transistor output stage, rather than a single capacitor-coupled output, and does not exhibit reduced bass response for any load.
What audio deficiency was found in the 3rd gen iPods? What kind of headphones could partially mitigate the bass response issues of the 3rd gen iPods? What is an example of a device that could entirely mitigate the bass response issues of the 3rd gen iPods? What part of audio output was substandard on 3rd generation iPods? What component was to blame for the weak bass of the 3rd generation iPod?