Unveiling the new Digital Linear PCM Recorder
The PCM-D1 features include 96 kHz-24 bit recording capability, 4GB internal Flash Memory, removable Memory Stick Pro High-Speed storage (optional) and a built-in USB port compatible with Macintosh and Windows/PC operating systems.
Says Jess Goedhals, General Manager of Sony Broadcast & Professional SA: “The PCM-D1 is lightweight, free of all drive mechanisms, equipped with highly sensitive electret condenser microphones, and designed with circuits that process stereo sound with virtually no extraneous noise. The body of this portable recorder is made of pressed titanium that's ten times harder than alumite-treated aluminium.”
Built-in electret condenser microphones
The PCM-D1's electret condenser microphones have extraordinarily high sensitivity and low noise characteristics. All the microphone casing parts fit together nearly seamlessly and are adjusted with 100-micron level precision. With a frequency response of nearly 30kHz, the microphones are positioned using an X-Y pattern and then angled toward each other with the left and right diaphragms close together, covering a wide sound range with reduced phase shifts. The result is rich audio with a natural sounding stereo image, good depth, and perspective.
Audio signal path
The microphone amplifier provided for each channel is the Analog Devices, Inc. AD797, which offers ultra-low noise and distortion. A variable gain circuit is adopted for amplitude control, which enhances the actual signal-to-noise ratio. The line amplifier provided for each channel is the Analog Devices AD8672. Analog and digital circuits are mounted on separate circuit boards and also separately powered to help prevent interference between circuit blocks. The analog circuit achieves superb linearity so that the recorded sound is output faithfully.
Construction quality
The circuitry of the PCM-D1 recorder is protected by a body made of 1mm thick, pure titanium and covered with nitrate titanium, scratch resistant coating - resulting in a finished titanium surface approximately ten times as hard as that of alumite treated aluminium. In addition, a distinctive arch-shaped polished stainless steel frame is provided to protect the microphones from impact damage. This rugged exterior protects the PCM-D1's circuits and microphones and enhances the high sonic quality of the recorder.
Simple Uploading to Computer
The PCM-D1 recorder conforms to the USB 2.0 Mass Storage Device standard. Because the recorder's native recording file format is .WAV, recordings can be quickly uploaded to a computer and used in conjunction with most common audioproduction software.
Signal processing
The PCM-D1 recorder offers comprehensive signal processing features for location recording including a unique limiter function, a 200Hz high pass filter and SBM (Super Bit Mapping) noise shaping. With the High Pass Filter enabled, audio below 200Hz is filtered out and not recorded. This function can be used to reduce noise caused by external sources such as wind, the flow of air-conditioning equipment, etc. With the SBM function enabled (optionally used for 16-bit recording modes), Super Bit Mapping significantly increases the dynamic range acoustically by reducing noise that is particularly easy to hear within the human audible band.
To improve the audio quality when converting 20-bit data into 16-bit, the top bits of information within the lower data (usually discarded when recording in 16-bit mode) are integrated into the 16-bit data track by shifting audible noise up into an inaudible higher frequency range.
Digital limiter
The digital limiter uses an independent audio buffer that contains audio 20dB lower then the audio processed in the normal recording signal path. With the PCM-D1 limiter enabled, when a loud sound suddenly occurs during recording, the over level part of the sound is automatically set within the range of the maximum input level (from the alternative -20dB buffer) in order to help prevent distortion. While this limiter function won't compensate for clipping of audio that is suddenly in excess of 20 dB, the sonic purity of the recording is fully maintained without the need to apply conventional limiter signal processing techniques.
High pass filter
With the High Pass Filter enabled, audio below 200 Hz is filtered out and not recorded. This function can be used to reduce noise caused by external sources such as wind, the flow of air-conditioning equipment, etc.
Super Bit Mapping
Super Bit Mapping significantly increases the dynamic range acoustically by reducing noise that is particularly easy to hear within the human audible band. To improve the audio quality when converting 20-bit data into 16-bit, the top bits of information within the lower data (usually discarded when recording in 16-bit mode) are integrated into the 16-bit data track by shifting audible noise up into an inaudible higher frequency range.
For more information on MediaTech Africa 2007, see: http://www.mediatech.co.za/
