Nagra V1

Wednesday, August 26, 2009

Six channel digital audio recorder – A Digital Location Recorder

Features
The Nagra VI is a 6 channels (4 Mic + 2 Line) digital location recorder, capable of 24 bit recording at 96 kHz. Post-production compatible (BWF files)(iXML compatible) with a large bright colour display. Timecode is to SMPTE / EBU with USB 2.0 communication. An internal 2.5” Hard drive disk and removable Compact Flash provide flexibility of recording media, all in a compact portable package. The Nagra VI also has an internal speaker.

Audio inputs
This machine offers six independent analogue audio inputs. Inputs 1 – 4 are equipped with traditional NAGRA microphone pre-amplifiers for dynamic and phantom +48V microphones. These pre-amplifiers are a combination of those developed for the NAGRA V and NAGRA-D and are without doubt the best audio inputs NAGRA has ever designed. An audio limiter can be selected for each of these inputs and these can be ganged in pairs if desired. These totally new concept input circuits offer the best specifications ever produced by any NAGRA in terms of pure audio quality. The four “In-house” transformers offer fully floating inputs for the dynamic microphones, giving a greatly improved signal-to-noise ratio. The remaining two analogue inputs are LINE level inputs for connection to other equipment supplying a line level signal, such as radio receivers. When set to the LINE position all 6 analogue inputs will accept up to +24dB. The two input connections (channels 5 + 6) double up as 2 AES inputs (A and B) when selected to digital input mode.

Zipper noise suppression
The NAGRA VI does not use traditional logarithmic potentiometers for the audio levels as were traditionally used on previous Nagra models. Today digital “encoders” are preferable because they do not suffer from “crackling” noise problems, and can be programmed to fulfill a multitude of different operations depending on the software program controlling them. Equally, even the graduation of the sweep is software calculated and can be altered relatively easily, rather than being created by the precision winding of the internal coils during manufacturing.
However, such encoders normally suffer from a phenomena known as the “Zipper” noise. The NAGRA VI benefits from a complex development in a suppression system used on every level control of the recorder. The end-result is that the potentiometers can be moved instantaneously and no digital zipper effect can be heard.
The potentiometers on the Nagra VI behave in exactly the same manner as the traditional logarithmic potentiometers used in Nagra analogue recorders but with the advantage of the precision offered by digitally controlled encoder devices, and hence an increase the perfection of all recordings.

Avalable are the analogue and digital audio input connections, but also the external 4 pole XLR DC input socket, allowing the NAGRA VI to be externally powered from an external DC power source such as a car battery. The 5-pin LEMO SMPTE/EBU time code In/Out can also be seen as well as the two HIROSE connectors used for powering external accessories such as radio receivers. These two connectors can supply up to 1 A at 12V.
On the right side of the recorder is where the removable compact flash card is located. A LED next to the slot indicates when the card is accessed. The stereo analogue outputs, and the main AES out as well as the second headphone connector can be clearly seen. Additional AES outputs are located on the 15 pin Extension connector. The Start / Stop terminal is a fader start (contact closure) command as found on other NAGRA recorders. Two USB (host / device) connectors are also located on the right side next to the card slot.

Recording medium and format
The NAGRA VI records to a 120GB internal 2.5″ hard disk. An extractable compact Flash card is used to record a copy of the audio tracks depending on the users track selections. The NAGRA VI allows approximately 20 minutes of 6 track 48 kHz 24-bit recording per GB of available disk / card space. The compact flash card section is equipped with a “Hot-Swap” possibility meaning that the CF card can be removed and replaced while the NAGRA-VI is powered up, without causing any damage to the card or the recorder. The NAGRA VI records using Broadcast Wave File (BWF) format and is iXML compatible for the metadata making the files compatible with all modern post-production equipment.

The NAGRA VI is equipped with a sunlight-readable 3.5″ colour TFT display with a resolution of 320 x 200 pixels. This specially designed high luminosity display is used to visually indicate not only the status of the NAGRA VI but also the bargraph modulometers, take number, time code and the current operating modes of the machine. When in the menu mode, the audio levels can be monitored using the LEDs on the front panel. A choice of user selectable screens can be displayed in the Test and Record positions, including the modulometers ONLY, according to the operators desire.

Channel mixing
The Nagra VI is able to mix the audio from 4 microphone inputs to a stereo mix on channels 5 + 6, or 5 analogue inputs to a mono mix on channel 6. Each microphone input level and L/R pan can be controlled using the arrow keys giving versatile mixing facilities. This mix channels can be recorded to the CF card in the copy process, as well as being recorded to the internal drive in the normal manner. If channels 5 + 6 are not being used for the mix, then all 6 inputs can be mixed either during recording, or subsequent replay, and the resulting mix fed to the line and AES outputs.

Media verification
The Nagra VI is equipped with a powerful routine to verify the read and write speed permitted by the different media (internal drive, CF card and USB drives). Certain “clone” or “fake” CF cards are available on the internet and the NAGRA VI allows the user not only to verify the digital id of the CF cards but also to check the read/write capacity of these media. Poor quality, low cost cards can cause severe problems when trying to write high bit rate linear PCM audio in real time.

File back-up
The NAGRA VI is equipped with two high speed USB 2.0 ports. One is designed to connect the NAGRA VI to a computer for file transfer. The second is a “host” connection and is used for connection of an external drive (USB key, external hard disk, DVD-RAM burner or an external device such as a USB keyboard.

Templates
The NAGRA VI can store up to six internal templates containing all the user selectable settings and parameters of the recorder. These can be individually named and recalled at any time to rapidly change the settings of the machine depending on the desired operating situation. Templates may also be stored on an external media (6 per media) as text files and can be edited using a simple text editor such as Notepad. This system allows the creation and use of partial templates if desired.

Time code
The internal time code system and all the internal digital electronics of the NAGRA VI are clocked by a crystal which is a “Stratum III” TCXO which has been artificially aged in an oven to maintain stability. This crystal gives a guaranteed overall stability better than ±4.6ppm over a period of 15 years throughout a temperature range from -20°C to +70°C. The drift due to temperature changes is less than 0.28ppm. This is the most accurate crystal ever used in an NAGRA recorder. The NAGRA VI will handle all the standard SMPTE / EBU frame rates as well as the 23.976fps rate for the HD format. All the frame rates can be pulled “up/down” for the NTSC markets.

The NAGRA VI has been designed as the natural successor to the NAGRA-D / DII multi-track digital recorders. Based on a totally new design concept, the hardware of the NAGRA VI is software dependent and can be adapted simply through software. Available in a choice of three colours (“Slate” grey, “Midnight” blue and “Burgundy” red) allowing owners of two or more recorders easily identify a particular unit. The NAGRA VI is supplied with two plastic “handles” which serve to protect the front of the unit from accidental damage, but can also be used to carry the recorder. A carrying case and shoulder strap are also supplied for over-the-shoulder operation.
The NAGRA VI is delivered with a removable battery box containing a lithium-ion battery pack, a mains power supply and is equipped with a 120GB internal hard disk.

Specifications

Recording
Data storage medium 120 GB Internal hard disk
Removable media Compact Flash type I / II (Hot Swappable)
Disk format FAT 32
Recording Method Linear digital PCM
File type 16 / 24 bit Broadcast Wave File BWF (WAV) with iXML, AES 31 compatible
A/D & D/A conversion 24 Bit Sigma Delta
Tracks 6 individual
Sampling Rate 44.1, 48 kHz, 88.2 and 96 kHz (with 0.1% pull up/down)
Recording capacity 20 mins of 6 track 24 bit 48 kHz per GB of disk / memory
Mono / polyphonic Selectable
Pre-recording buffer Up to 10 seconds @ 96 kHz 24-bit on 6 tracks
Display 3.5 inch colour TFT LCD
Level meters On colour display AND by LED for microphone inputs

Inputs
Digital inputs 2 x XLR AES-3 shared with analogue inputs 5+6
Analogue inputs
4 x symmetrical XLR Microphone (Dynamic, +48V Phantom) / line
Microphone input sensitivity 2.8 and 10 mV/Pa selectable
Limiters Selectable on microphone inputs, individual or in pairs. Active at -7.6dBFS, max +40dB for -2 dBFS
Line input sensitivity Adjustable from -6 dBm up to +24 dBm for 0 dBFS recording
THD at 1 kHz <0.1% Mic, <0.01% line (measured on AES out)
Frequency response Mic, 10Hz – 48 kHz ± 0.5 dB, Line ±0.2 dB (measured on AES out)
Input noise with condenser mic 0.88 µV (-119 dBm)
Input noise with dynamic mic 4 dB (measured ASA “A” loaded 200Ω
Signal-to-noise ratio >114 dB
Input level adjustment range 50 dB Mic and from -6 to +24 dB Line
Input filters LFA (with vortex filtering)
Slate microphone Electret behind the front panel

Outputs
Analogue line output 2 x XLR 4.4V max (+15 dBm)
Digital output XLR AES-3 (24 bit or 16 bit dithered)
Headphones 2 x Stereo 6.3mm (¼”) Jack 50 Ω
Internal speaker 1W

Other
USB Host USB 2.0 connector type “A”
USB Device USB 2.0 connector type “B”
Time code IN/OUT 5 pin LEMO (SMPTE / EBU)
M/S Decoder Switchable
Word Clock 9-pole “D” type connector
Dither Menu selectable 24/16bits on Inputs and/or Outputs

General
Dimensions 310 x 74 x 285mm (W x H x D) (Incl. battery box)
Weight 3.8 kg (8.3 lbs) (with battery pack)
Power supply Lithium-Ion, or external 9 – 16V (XLR 4 pole)
Power Consumption Approximately 10W
Charge time 3 hours (with supplied Lithium-Ion pack)
Ext. power out 2 Hirose 12V (max 1A)
Operating temp. From -20°C to +60°C (without internal hard disk)
From 0C to +50C (Hard disk installed)
Relative humidity From 10% to 99% (non condensing)

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Tags: 24 Bit, Nagra, Phantom power, recorder, Timecode

This entry was posted on Wednesday, August 26th, 2009 at 8:34 pm and is filed under Location Recorders. You can follow any responses to this entry through the RSS 2.0 feed.