monaural microphone 
WS-311M, WS-321M, WS-331M specifications
The Olympus WS series of digital voice recorders, specifically the WS-331M, WS-321M, and WS-311M, are designed for users seeking high-quality audio recording in a compact and portable form factor. These models are particularly favored by professionals, students, and journalists for their user-friendly features and superior sound quality.The WS-331M is the flagship model among the three, boasting advanced features that enhance recording versatility. It includes a high-fidelity stereo microphone system, which captures clear and detailed audio in various environments. The WS-331M offers a recording time of up to 4 GB, allowing extensive recording sessions without the need for immediate file management. It also supports a variety of recording formats, including PCM for high-quality recordings, ensuring professional-grade sound fidelity.
The WS-321M strikes a balance between performance and affordability. It features a similar design and functionality to the WS-331M but is equipped with a slightly lower recording capacity. Nonetheless, it still offers impressive audio quality with its built-in stereo microphones and an intuitive interface that simplifies the recording process. The WS-321M also includes a voice activation feature, enabling hands-free recording, which is ideal for capturing lectures and interviews.
The WS-311M is the most basic model in the series, but it does not compromise on essential features. It provides solid performance with its built-in microphones and user-friendly controls. The WS-311M is particularly suitable for casual users who need a reliable recorder for everyday use. With a smaller memory capacity compared to its siblings, it still offers ample recording time for personal notes and reminders.
All models within the WS series integrate Olympus' well-known technologies, such as noise cancellation and voice filter features, which enhance audio clarity by eliminating background noise. The devices are lightweight and portable, making them easy to carry around for on-the-go recording. Battery life is impressive across the models, allowing for extended usage without frequent recharging.
In summary, the Olympus WS-331M, WS-321M, and WS-311M provide a range of digital voice recording solutions that cater to various user needs. With their high-quality audio capabilities, user-friendly interfaces, and innovative features, these recorders stand out as dependable tools for anyone in need of reliable voice recording technology.