About the internal hard disk drive

The internal hard disk drive (HDD) is a fragile piece of equipment. Please use the recorder following the guidelines below to protect against possible HDD failure.

We recommend that you back up your important recordings onto DVD discs in order to protect against accidental loss.

Do not move the recorder while it is on.

Install and use the recorder on a stable, level surface.

Do not block the rear vent/cooling fan.

Do not use the recorder in excessively hot or humid places, or in places that may be subject to sudden changes in temperature. Sudden changes in temperature can cause condensation to form inside the recorder. This can be a cause of HDD failure.

While the recorder is switched on, do not unplug from the wall socket or switch the electricity off from the breaker switch.

Do not move the recorder immediately after switching it off. If you need to move the recorder, please follow the steps below:

1.After the message POWER OFF is shown in the display, wait at least two minutes.

2.Unplug from the wall socket.

3.Move the recorder.

If there’s a power failure while the recorder is on there is a chance that some data on the HDD will be lost.

The HDD is very delicate. If used improperly or in an unsuitable environment, it is possible that the HDD will fail after a few years of use. Signs of problems include playback unexpectedly freezing and noticeable block noise (mosaic) in the picture. However, sometimes there will be no warning signs of HDD failure.

If the HDD fails, no playback of recorded material will be possible. In this case it will be necessary to replace the HDD unit.

Introduction

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NEC NDH-81 owner manual About the internal hard disk drive

NDH-81 specifications

The NEC NDH-81 is a high-performance headphone designed to deliver an exceptional audio experience, using a blend of advanced technologies and ergonomic design. This model is recognized for its professional-grade sound quality and is particularly appealing to audiophiles and sound engineers alike.

One of the NDH-81's standout features is its closed-back design, which provides excellent sound isolation. This allows users to immerse themselves in the music without distractions from ambient noise. The headphones utilize a well-engineered bass reflex system that enhances low-frequency response while maintaining clarity across all ranges. This ensures that listeners can experience deep bass without sacrificing the integrity of mid- and high-frequency sounds.

The NDH-81 is equipped with large, high-fidelity 38mm dynamic drivers. These drivers are meticulously crafted to ensure a balanced sound stage, making it suitable for critical listening and professional audio applications. The headphones have an impressive frequency response range, typically between 5 Hz to 40 kHz, which encompasses the full spectrum of human hearing. This broad range allows for accurate reproduction of audio signals, capturing nuances that are often lost in lower-quality headphones.

Comfort is another essential aspect of the NDH-81. The headphones feature plush, breathable ear pads made from soft velour material. This ergonomic design ensures enduring comfort during extended listening sessions, crucial for professional use where long hours of wear are common. Additionally, the adjustable headband provides a secure fit without causing fatigue.

Another innovative technology incorporated into the NDH-81 is its impedance compatibility. With an impedance of 24 ohms, these headphones can be driven effectively by a wide variety of devices, from portable audio players to professional studio equipment. This versatility allows clients to utilize the NDH-81 across different audio setups without compromising sound quality.

The build quality of the NEC NDH-81 also deserves attention. Constructed with durable materials, these headphones are built to withstand the rigors of everyday use, ensuring longevity and reliability. Furthermore, the detachable cable feature adds to the practicality of the design, allowing for easy replacement in case of wear and tear.

In conclusion, the NEC NDH-81 stands out in the competitive headphone market due to its combination of advanced audio technologies, comfortable design, and durable construction. Whether for professional studio work, critical listening, or casual enjoyment, the NDH-81 offers a compelling solution for sound enthusiasts seeking quality and performance.