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Author Topic: NJB3 operating FAQ v1.4a  (Read 5245 times)

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Offline Brian Skalinder

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NJB3 operating FAQ v1.4a
« on: March 29, 2004, 08:52:02 PM »
From the NJB3 Yahoo tapers group.

********************************************************************
* RECORDING WAV FILES ON THE NJB3                 ******************
* v1.4a - 02/11/2004                               ******************
********************************************************************

Contents:
-Introduction
-Analog Recording
--Recording
--Monitoring
--Stopping
-Digital Recording
--Recording
--Monitoring
--Stopping
-Transferring Files
-Terms And Other Information

***************************************
* INTRODUCTION ************************
***************************************

The most current Operating System (OS) Firmware for the NJB3 is 1.40.06.

A majority of 1.40.06 users have no problems with this firmware.  Creative
has added a few important recording-related updates and fixes with this firmware:

* Adds support for up to 16,000 songs
* Adds a new continuous recording feature where very long recording
sessions are automatically divided into separate tracks
* Resolves the recording break issue so that a recording session is seamless
when divided into separate tracks using the Fast Forward button

The NJB3 has both Analog and Optical Digital inputs. Along with having
Optical input, the NJB3 also has the ability to record to MP3 format on the
fly! Although this can be a great benefit for some types of recording, we
won't use the MP3 format in the following examples.

It might be a good idea to have the NJB3 powered via the AC adapter for
these examples:

******************************************************
*                            *************************
* ANALOG RECORDING WITH NJB3 *************************
*                            *************************
******************************************************

The NJB3 has a stereo analog line level female input "jack" on the left side
of the unit. You will need a male "plug" to attach to it.

The devices that you will use as sources for analog recording may have any
number of connector types, but the most common are known as "RCA PHONO"
type. These are found on the back of many, if not most, pieces of consumer
home audio gear. In order to use devices that have these kind of connectors
as sources, you will need to acquire a cable that has a single "3.5mm
trapezoidal-tip TRS" plug on one end for the NJB1 and two "RCA PHONO" type
plugs on the other, one for Left and one for Right. This type of adapter
cable can commonly be found at Radio Shack as well as many other outlets.

Attach the cable between the units like this:

   Source Device     cable    NJB3
+-----------------+        +---------+
| Aux/Line Outs  L|---\    |         |
|       or        |   +--->| Line In |
|   Tape Outs    R|---/    |         |
+-----------------+        +---------+

**********************
* RECORDING **********
**********************

With OS 1.40.06 and prior running on the NJB3,

   * Press [MENU] to get to the Menu screen.
   * Scroll to "Record Audio".
   * Press the Scroll Wheel to select.
   * You will now be at the "Record Settings" screen.

You now need to determine what NJB3 input you are going to use for your
Source. In this case it will be "Line-In". If it's not already selected,
scroll to the "Source:" line and press in on the Scroll Wheel, scroll to
"Line-In" and press the Scroll Wheel again.

Now scroll to the "Synchro:" line and make sure that it's set to "Off". If
not, press the Scroll Wheel again, scroll to "Off" and press the Scroll
Wheel to select. This "Synchro" feature is intended to auto-magically divide
the recording up into separate tracks and, like most robots, it can get
confused easily. I would NOT recommend using this feature to start with.

Scroll back up to the "Monitor Recording" line and press the Scroll Wheel
again. You should now see the "Line-In Recording" screen. Now we need to
figure out what kind of file we want to create. The default that you will
see is "MP3, 128kbps". This means "MPEG1 Layer3 at 128 kilobits per second".

A little detour ... MPEG1 Layer3, or MP3 as it is more commonly referred to,
is a "bit-reduced" method of audio encoding, sometimes called a
"lossy-compression" type of algorithm. This means that some of the audio
information is actually THROWN AWAY! This produces much smaller files, but
they are of LOWER QUALITY than the "linear" or "non-bit-reduced" .WAV type
of encoding. It may be that upon hastily listening to an MP3 encoded file,
you will find that it sounds "OK" or even "Really Good". This impression can
rapidly change when listening to the same file in a more critical
environment. Your impression definitely WILL change if the file is copied by
analog means and re-encoded with MP3 then copied again using ATRAC (the
MiniDisc bit-reduction scheme) or WMA or OGG or any of the other
"lossy-compression" algorithms. This kind of thing happens all the time and
is known as "cascading" bit-reduction schemes. Each time the material is
re-encoded, another part of the audio is literally thrown away. At some
point, the audio "breaks" and the material becomes unlistenable, if not
unplayable. This would suggest that "Master" recordings should be made in
non-bit-reduced or "linear" form (PCM WAV for example) and that copies
should be made on a one-to-one basis by copying the data in digital form.

The NJB3 is capable of recording files of the following types via it's
Analog Line In:

Bit-reduced:
MP3 at 64, 96, 128, 160, 192, 256 and 320kbps bit rates

Non-bit-reduced:
WAV at 11.025, 22.05, 44.1, and 48kHz sample rates

Since we are concerned with trying to make high quality analog recordings on
the NJB3, the WAV format with a sample rate of at least 44.1 should be used.
The 44.1kHz rate is the same as CD's use so, if you record at this rate,
it's possible to burn CDs directly from the files produced on the NJB3. The
48kHz rate will increase the recorded bandwidth slightly but will not allow
you to write playable CDs from the files without "downsampling" and losing
the extra bandwidth.

So ...

You should still be at the "Line-In Recording" screen. We need to select
.WAV at 44.1kHz by scrolling to the "Format:" line and pressing the scroll
wheel. Now scroll up to "WAV, 44.1KHz" and press the scroll wheel again to
select.

The next thing to decide is whether the input level to the NJB3 needs to be
adjusted. The metering will provide clues. When you play your source device,
you should see the 2 meter bars in the bottom right corner of the NJB3
"Line-In Recording" screen start to bounce around a bit. There are 3 lines
of LCD pixels at the bottom that will be lit when the -59dBfs threshold is
reached. There are then single line increments up to the -1dBfs point,
followed by 2 separate lines at the very top that signify "clipping".

The segments between the -59dBfs indication and "clipping" or "full scale"
indicate acceptable audio levels. With the "Gain:" set to "0", a -10dBv
input level should cause the meter to be lit about halfway up, resulting in
a recorded level of -20dBfs.  This could be considered to be similar to "0
VU" on traditional mechanical VU meters. In other words, it's the place
where the meter scale would start going "Into The Red".

If the program material that you are attempting to record is not within
these limits, you need to adjust the level. Probably the best approach is to
do so outside of the NJB3. Unlike it's brother the NJB1, if it's not
possible to adjust the level outside the NJB3, you may use the "Gain:"
setting to bring it into acceptable limits without much, if any, negative
impact on the Signal to Noise Ratio. It's best to be conservative and set
the Gain to a level that will NEVER cause the "clipping" indicator to light.
It's possible for short transients to cause clipping that will not be
indicated on the meters. For this reason you'll probably want to make sure
that the meters don't show anything even close to the -1dBfs indication for
unprocessed dynamic material.

For the moment, let's assume the levels are fine.

Next you need to initiate record on the NJB3 by pressing the [>/||] or
[PLAY] button. The message "Preparing Recording ..." will pop up. Unlike the
NJB1 which records in file "chunks" of 15 minutes, the NJB3 records to a
file continuously until the file is "full". For .WAV type files, the limit
is 2:59:59 or 3 hours. For .MP3 files it's 9:59:59 or 10 hours. This can be
thought of as either an asset or a liability:

LIABILITY - You are limited to 3 hours of truly continuous recording in WAV
format. The resultant file size of a 3 hour recording is nearly 2GIGS! This
*can* take a long time to transfer via USB and may "choke" some older sound
editing programs. When in the process of recording, it IS possible to close
the current file and start a new one fairly rapidly by pressing the [>>|] or
[FORWARD] button but this will result in a gap of a couple of seconds. If
the batteries run down sufficiently during a recording session, the NJB will
close the current file before shutting off. If you are using AC power and
the batteries are either not installed or they are run down too far and
somehow power is interrupted to the unit before the end of the recording,
you are screwed! There is currently no way to recover an unfinished/unclosed
recording.

ASSET - Unlike the NJB1, there is no need to "stitch together" a bunch of 15
minute segments. The provision for quickly closing a recorded file and
opening a new one minimizes potential "down time". Firewire transfers can be
relatively rapid, reportedly as little as 5 minutes per 3 hour recording!

**************************************
* MONITORING WHILE RECORDING *********
**************************************

It's ALWAYS a good idea to monitor the progress of your recording. Make sure
that you have a set of headphones for the unit and LISTEN! If you are using
battery power for recording, constant use of the headphones can drain the
battery, but it's a good idea to listen in occasionally. Pay attention to
the meters on the NJB3 and make sure the input doesn't cause the last meter
segments to light. This indicates that offensive clipping distortion may be
occurring. Turn it down by either adjusting the signal at it's source, or
using the "Gain" control on the NJB. If you do adjust the NJB "Gain" while
recording, there will be momentary glitches, so it's best to be conservative
and set the levels accordingly at the start to avoid compromising your
recording.

**************************************
* STOPPING RECORDING *****************
**************************************

When you are finished recording, press the [STOP] button (the one below the
[>] or [PLAY] button). You will see a prompt that says "Processing ..."
while the file is being closed, then "Saved".  With OS 1.40.06, when you
press the FastForward [>>] button, the Jukebox will save the current recording
and start a new file with a very minimal gap.  Creative claims a "seamless"
transition (implying no dropped samples), however users report between 10-30
samples are actually dropped.  This is less than a half-second and is much
faster than a DAT tape change is.  :)

******************************************************
*                             ************************
* DIGITAL RECORDING WITH NJB3 ************************
*                             ************************
******************************************************

The NJB3 uses an Optical Digital Input for receiving data. This connector is
actually contained in the same jack as the Analog Line-In. The Optical plug
used to connect to this jack looks very similar to a normal 3.5mm plug
except that the Tip portion contains the optical fiber. This connector is
becoming more and more popular but still may be somewhat scarce. Try Radio
Shack!

A large number of audio devices use a different kind of connector known as
"TOSLINK" that has a square housing with the optical fiber held in the
center. If you intend on using a device with a TOSLINK connector as your
source, you will need an appropriate adapter cable.

If your source device has SPDIF on RCA Phono type connector or AES-EBU on
XLR connector for Digital output, you'll need to acquire a SPDIF/AES-EBU to
TOSLINK converter and appropriate cables.

**********************
* RECORDING **********
**********************

With OS 1.40.06 running on the NJB3,

   * Press [MENU] to get to the Menu screen.
   * Scroll to "Record Audio".
   * Press the Scroll Wheel to select.
   * You will now be at the "Record Settings" screen.

You now need to select the "Optical-In" on the NJB3 to use with your Optical
Digital Source. Scroll to the "Source:" line and press in on the Scroll
Wheel, scroll to "Optical-In" and press the Scroll Wheel again. Now scroll
to the "Synchro:" line and make sure that it's set to "Off". If not, press
the Scroll Wheel again, scroll to "Off" and press the Scroll Wheel to
select.

Scroll back up to the "Monitor Recording" line and press the Scroll Wheel
again. You should now see the "Optical Recording" screen. Now we need to
figure out what kind of file we want to create. As in the Analog Line In
recording section, the default that you will see is "MP3, 128kbps". This
means "MPEG1 Layer3 at 128 kilobits per second".

The NJB3 is capable of recording and writing files of the following types
via its Optical Line In:

Bit-reduced:
MP3 at 64, 96, 128, 160, 192, 256 and 320kbps bit rates

Non-bit-reduced:
WAV at 32, 44.1, and 48kHz sample rates

As in the Analog recording section, we want to change this to .WAV type for
the highest fidelity. Unlike the Analog Line In Format selections, the WAV
type has no associated sample rates. That's because the sample rate
information should be contained in the optical data stream coming from the
source device. As mentioned previously, the data stream must be SPDIF
compliant with the sample rate information embedded in the appropriate
places in order for the NJB3 to correctly identify it. If the NJB3 doesn't
find this information, it will write files that report the default 44.1kHz
rate regardless of their actual rate. The SPDIF data stream can only report
32, 44.1 and 48kHz rates. The CODEC chip in the NJB3 may receive at other
rates and the NJB3 may write the resulting data to disc, but it will not
correctly report the sample rate information and the metering will not be
accurate.

So ...

You should still be at the "Optical Recording" screen. We need to select
.WAV at 44.1kHz by scrolling to the "Format:" line and pressing the scroll
wheel. Now scroll up to "WAV" and press the scroll wheel again to select.

The next thing to decide is whether the input level to the NJB3 needs to be
adjusted. The metering will provide clues. When you play your source device,
you should see the 2 meter bars in the bottom right corner of the NJB3
"Line-In Recording" screen start to bounce around a bit. There are 3 lines
of LCD pixels at the bottom that will be lit when the -59dBfs threshold is
reached. There are then single line increments up to the -1dBfs point,
followed by 2 separate lines at the very top that signify "clipping".

The segments between the -59dBfs indication and "clipping" or "full scale"
indicate acceptable audio levels. With the "Gain:" set to "0", a -10dBv
input level should cause the meter to be lit about halfway up, resulting in
a recorded level of -20dBfs.  This could be considered to be similar to "0
VU" on traditional mechanical VU meters. In other words, it's the place
where the meter scale would start going "Into The Red".

If the program material that you are attempting to record is not within
these limits, you may need to adjust the level. It's not possible to adjust
the level inside the NJB3 when using the Optical input so you will have to
accomplish this before it reaches the NJB3. It's best to be conservative and
set a level that will NEVER cause the "clipping" indicator on the NJB3 to
light. It's possible for short transients to cause clipping that will not be
indicated on the meters. For this reason you'll probably want to make sure
that the meters don't show anything even close to the -1dBfs indication for
unprocessed dynamic material.

For the moment, let's assume the levels are fine.

Next you need to initiate record on the NJB3 by pressing the [>/||] or
[PLAY] button. The message "Preparing Recording ..." will pop up. Unlike the
NJB1 which records in file "chunks" of 15 minutes, the NJB3 records to a
file continuously until the file is "full". For .WAV type files, the limit
is 2:59:59 or 3 hours. For .MP3 files it's 9:59:59 or 10 hours. Again, this
can be thought of as either an asset or a liability:

LIABILITY - You are limited to 3 hours of truly continuous recording in WAV
format. The resultant file size of a 3 hour recording is nearly 2GIGS! This
*can* take a long time to transfer via USB and may "choke" some older sound
editing programs. When in the process of recording, it IS possible to close
the current file and start a new one fairly rapidly by pressing the [>>|] or
[FORWARD] button but this will result in a gap of a couple of seconds. If
the batteries run down sufficiently during a recording session, the NJB will
close the current file before shutting off. If you are using AC power and
the batteries are either not installed or they are run down too far and
somehow power is interrupted to the unit before the end of the recording,
you are screwed! There is currently no way to recover an unfinished/unclosed
recording.

ASSET - Unlike the NJB1, there is no need to "stitch together" a bunch of 15
minute segments. The provision for quickly closing a recorded file and
opening a new one minimizes potential "down time". Firewire transfers can be
relatively rapid, reportedly as little as 5 minutes per 3 hour recording!

**************************************
* MONITORING WHILE RECORDING *********
**************************************

It's ALWAYS a good idea to monitor the progress of your recording. Make sure
that you have a set of headphones for the unit and LISTEN! If you are using
battery power for recording, constant use of the headphones can drain the
battery, but it's a good idea to listen in occasionally. Pay attention to
the meters on the NJB3 and make sure the input doesn't cause the last meter
segments to light. This indicates that offensive clipping distortion may be
occurring. Turn it down ... SOMEHOW!

**************************************
* STOPPING RECORDING *****************
**************************************

When you are finished recording, press the [STOP] button (the one below the
[>] or [PLAY] button). You will see a prompt that says "Processing ..."
while the file is being closed, then "Saved".

**************************************
* TRANSFERRING FILES *****************
**************************************

Like the NJB1, The NJB3 has no editing functions. In order to manipulate the
audio files created on the NJB3, you must transfer them to some other device
that is capable of editing. The BEST approach is to transfer the files in
the digital domain via the USB or Firewire port to a PC that has audio
editing software installed. This way, each file can be transferred faster
than real-time with no loss of audio fidelity. You can edit the content and
burn a CD of the results with no audio degradation.

In order to transfer the files from the NJB3 to computer, you need to
install software on the computer such as Creative Lab's "Playcenter", Red
Chair's "Notmad Explorer" or Perlogic's "JBHTTP" among others. These
programs allow the NJB3 and the computer to communicate via the USB or
Firewire connection. Depending on which of these programs you use, the
presentation of filenames and such may differ. Consult the instructions for
your software about how to establish a connection. Browse to the NJB file
listings under "RECORDINGS" or "ALL TRACKS" and look for the files that were
created during your session.

It's also possible to transfer files from one NJB3 to another via the
Firewire ports ...

*************************************************
* TERMS AND OTHER INFORMATION *******************
*************************************************

1) This document refers to features found in the most current NJB3 firmware
revision (1.40.06) as of 2/11/2004.

2) The term "Line Level" refers to "Consumer Line Level" which is
nominally -10dBv and unbalanced. This is the electrical specification that
most consumer audio products use for their "Line Out", "Line In", "Tape Out"
and "Tape In" connections. Both the NJB1 and NJB3 use this general type of
electrical level.

3) The term "Mic Level" refers to a nominal -60dBv level signal. This is a
much lower electrical level than "Line Level". Neither of the NJBs properly
handle this kind of level for stereo recording. The NJB3 is somewhat
confusing in this regard. There are currently provisions in the NJB3 OS that
provide the ability to "adjust" for what is called "Mic-In" but these
"adjustments" can result in a serious deterioration of the Signal to Noise
Ratio (SNR). Refer to the section on Analog Recording for the NJB3. Neither
the NJB1 nor NJB3 provide "microphone power" for electret condenser mics on
their Input jacks.

4) The NJB3 has a stereo analog line level female input "jack" located on
the unit. You will need a male "plug" to attach to it. These connectors are
of the 3.5mm TRS (Tip/Ring/Sleeve NOT Tandy Radio Shack) trapezoidal-tip
type commonly referred to as "Walkman headphone connectors". This is NOT an
1/8inch "mini phone" type connector! DO NOT USE A 1/8INCH PLUG IN THESE
3.5mm JACKS! It will eventually, if not immediately, break the jack and
render your NJB useless for recording purposes.

5) The NJB3's 3.5mm analog Line In jack also doubles as an Optical Input
jack. This type of jack mates with a special 3.5mm Optical plug. In order to
use the NJB3s' Digital Optical Input you will need an optical fiber cable
with this type of plug on at least one end.

6) There appears to be much confusion about the difference between a "Mic
Preamp" and a "Battery Box".

- A "Mic Preamp" is a device capable of providing "gain" or "amplification"
to the relatively low-level microphone signal. It brings the signal up to
"Line Level" that is needed to drive the input of your NJB. The amount of
gain required depends on the sensitivity of the microphones (unit of
electrical energy per unit of pressure), the Sound Pressure Level (SPL) of
the event to be recorded and the voltage required to drive the input of the
NJB to just below clipping. This could be as much as 60 or more decibels
(dB). Typically, a Mic Preamp will also provide things like input padding,
phase reversal and phantom power. A Mic Preamp can be purchased for as
little as $60.00 or as much as several thousand dollars.

- A "Battery Box" is just that, a box that contains batteries required to
power electret mics. Neither the NJB1 nor the NJB3 provides the low level DC
"microphone power" that is commonly found on portable MiniDisc and Cassette
machine Mic-Inputs. There are a number of companies that sell miniature
electret microphones intended for "stealth" event recording that also sell
these Battery Boxes. The Battery Box itself does NOT provide gain, just DC
power to make the mics work. Some of these boxes may have a "volume knob"
that simply attenuates the mic level signal. This should not be confused
with a Gain control. Some of these same companies also sell OPTIONAL
microphone preamps that may be built in to the Battery Box. Remember that
you may need as much as 60dB or more of clean gain in order to properly
drive the input to your NJB depending on the event and the microphones.
Quite often, low cost microphone preamps are constructed with minimal parts
and can only provide 20dB or so of gain. This may not be enough.

7) Digital converters and "SCMS Strippers" may do more than simple media
conversion or stripping of the SCMS bits. There are a huge number of digital
standards converters on the market. Some of them "resample" the input to an
internal rate, perform whatever manipulations are required, and then
possibly "resample" yet again for output. Some of these devices work better
than others. It may be that for your purposes, the digital optical input on
the NJB3 can simply be plugged into your source device via standard CONSUMER
SPDIF/TOSLINK equipment. If so, it's probably best not to introduce any
potential problems by adding more crap to the chain. The NJB3 expects the
incoming data stream to adhere to the CONSUMER SPDIF de facto standard. If
the Sample Rate information is not in the appropriate place in the data
stream and you are using a rate of 32kHz or 48kHz, the NJB3 will NOT
correctly identify the sample rate, your resultant files will be written as
44.1kHz and the meters will NOT accurately reflect the level of the incoming
signal.

**********************************************************************
* Original Author: T G MARTIN 06/11/2003            ******************
* Contributors: M WREN                              ******************
*                                                   ******************
* v1.2 06/11/03 - original release                  ******************
* v1.3 07/07/03 - TGM incorrect statement about no  ******************
*                 metering in OS 1.20.06 removed.   ******************
* v1.4a02/11/04 - Added info on OS 1.40.06          ******************
*                                                   ******************
* If you add to or edit this document, please       ******************
* make notes here and change the version number     ******************
* and date at the top. Thanks, and I hope this      ******************
* is found to be useful by someone! -Tim            ******************
**********************************************************************
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