Before revision: Most commonly they are found embedded in electronic devices that have a headphone jack, such as integrated amplifiers, portable music players (e.g., iPods), and televisions, but standalone units are used, especially in music studios and in audiophile markets .
After revision: Most commonly they are found embedded in electronic devices that have a headphone jack, such as integrated amplifiers, portable music players (e.g., iPods), and televisions, but standalone units are used, especially in audiophile markets and in professional audio applications, such as music studios .