Recording

[Craig Maier]

Record


This is the button with the red square. It is used to place the DCArt10/DC Forensics10 program into Record mode. You can also access this function by hitting the Ctrl + R Hotkey. Pressing either the hot keys, menu item or clicking on the Record button will activate the Recording Window. From there, you see the following dialog box:


The Recording Window

• Recording Level Meters- Just like on a standard audio or video recorder, you press the Pause button on the Record window, start your source audio playing, and these meters will indicate the amount of signal flowing into your sound card. No level adjustment can be made here. Simply go to your sound card’s mixer to increase or decrease the signal.
• Recording Device- If you’ve set up your sound card(s) correctly, this list will display them and allow you to choose your desired recording device. If nothing is displayed here, it’s time to revisit both Windows and your sound card installation instructions. The recording device setup is also available under the Edit/Preferences/Soundcard pathway.
• VOX Recording- This check box activates VOX recording. If you want to trigger your recorder automatically on some sort of input signal, this is where it happens. You simply set a Trip Level that is measured in dB. Record will remain paused until a signal above the level you’ve indicated is received on input. Record will stop when the system senses no input at that level for a period determined by the “Minimum Duration” settings. For more info, see below.

Trip Level - Threshold Range is from +1 dB to –100
dB. This “trips” the system into recording when the
desired level is reached.
Minimum Duration - Time Range is from 0 to 360
seconds. After the system begins to record, it will stop
automatically when the desired signal stops occurring for
the amount of time you’ve dictated in this field.

• Channels - Allows you to select Mono (1 channel) or Stereo (2 channel) recording
• Sample Rate - Allows you to choose your desired sampling rate. Here are the choices:
  1. 192.00 or 96.00 kHz- Normally associated with DVD recording and playback, these sampling rates provide bandwidth well beyond the audio spectrum and consumes disc space at very high rates.
  2. 48.00 kHz- This rate will produce slightly higher values of bandwidth than 44.1 kHz, but is primarily used for pro-audio applications. It’s effective top-end bandwidth is just shy of 24 kHz.
  3. 44.10 kHz- This rate will produce a full 20 kHz recording bandwidth, and it consumes disk space at a moderate rate - - - 5.29 Mbytes per minute per input channel. This is the same sampling rate used on commercial Compact Discs.
  4. 22.05 kHz- This rate will produce a recording bandwidth of around 10 KHz, which is adequate for the restoration of old acoustical recordings. This setting consumes disk space at the rate of 2.645 Mbytes per minute per input channel.
  5. 11.25 kHz- (This rate will produce a recording bandwidth of only 5 kHz, which is useful for the restoration of old spoken word recordings, telephone conversations, and first generation movie soundtracks.) It consumes disk space at the lowest rate of only 1.3225 Mbytes per minute per input channel.
  6. Custom- Using this setting, you can fill in any sampling rate you choose under the Custom “Sample Rate (Hz)” field via your keyboard. This could be useful in some situations, provided your sound card can support anything but the standard sample rates. The range of sample rates which can be entered as a Custom value is any integer extending from 100 Hz up to 210,000 Hz (210 kHz). Your sound card/sound card driver may limit this range of capability.

• Sample Rate (Hz) - If you choose “Custom” sampling rate, this is the field where you can manually type in the sampling rate you want. (Your sound card must support this rate, however in order for it to work properly.)

• Resolution - This is where you’ll choose the bit width of your recording. You can choose from the following:
  1. 1. 8 Bit (used mostly for Forensics & Games)
     2. 16 Bit (most common - CD Quality PCM Audio)
     3. 20 Bit (un-common professional grade audio)
     4. 24 Bit (common professional grade audio)
     5. 32 Bit Float (Floating Point for special applications)
     6. 32 Bit Int (Integer for special applications)

• Record Position - This window, like the tape counter on your tape deck, simply tells you where you are in your recording.
• Transport Controls - Just like a common tape recorder, you can Rewind, Pause, Record, Stop, and Fast Forward in your recording.
• Current System Status- This gray box normally defaults to the “Stopped” position, but also turns Red while recording and Yellow on “VOX Waiting” mode. It is shown in Green when in the “Paused” mode.
• Free Disk Space - Tells you how much space is available for recording on your hard disk.
• Available Recording Time - Does a quick calculation on the fly of your hard disk space, sampling rate, bit width and gives you an estimate of how much recording time remains.
• Spacebar Control - Normally, the spacebar controls audio playback. However, when the record dialog box is showing, the spacebar reverts to a toggle function alternating between record and record-pause mode of operation.

VOX Recording


As indicated above in the Record window, VOX (Voice Operated Xmit {transmit} – an old military communications term), or signal activated recording, is possible with DCArt10/DC Forensics10. This feature allows the Diamond Cut recorder to start and stop itself based on the presence or lack of presence on an audio input signal. The recording activation process is triggered by signal level sensing as determined by your setting of the Trip Level control. The record de-activation process is triggered by a combination of the signal level sensing system in conjunction with the Minimum Duration control setting. For example, you will want to set the Minimum Duration to a value long enough so that the recorder does not stop between songs on an LP. In that example, you would probably want to set the control for about 10 seconds. To use the VOX feature, bring up the Recording dialog box and check VOX recording and set the Trip Level and Minimum Duration appropriately for your specific application.

In the DC Forensics10 Version, you can also perform automatic time stamping of VOX events when you have the Log to Disk function selected (see the Live Mode section for more information). This function adds a time stamp for each recording event and is accurate to less than 1 second. It is very useful for Forensics surveillance recording situations. Extended Recording

Record Material of any Length- No More 2 Gbyte Wave file Limit


Wave files are limited in length to 2 Gbytes. In some situations, it is desirable to record for a period of that exceeds this 2 Gbyte limit. The
Extended Recording Feature accommodates this situation. It works by automatically opening a new file when a particular file approaches the 2 Gbyte limit. When you save the extended file(s), you will see that the file(s) will be named in the following format in your directory of choice:

xxx_part1.wav
xxx_part2.wav
xxx_part3.wav
xxx_partn.wav

Each file will have to be played or processed independently thereafter.
Recording Signals onto your Hard Drive (Tutorial)

1. Before making your first recording, please quickly review the tutorials for “Getting Started”.
2. This process needs only to be performed once, if you only have one sound card. Your chosen setting will be saved. However, if you have multiple sound cards, this process will have to be repeated anytime you desire to change the input or output configuration to DCArt10/DC Forensics10.
3. Now, click on the Red Record button found on the toolbar. You will see the Record dialog box appear on your screen. Determine your settings and select the desired recording device from the drop down window.
4. Click on the Pause (Record Pause) button in the recording window. If your source is analog, adjust the output level of the sound source or the input sensitivity of your sound card until the green VU meter bar graphs are modulating vertically to the maximum degree possible short of activating the red overload indicators. Please note that this adjustment may consist of a hardware control (gain or volume) of the output signal feeding into your sound card OR you may use the input mixer of your sound card to perform this function. Sample the loudest portion of the sound source to assure that no overloading will occur when the transfer is made to your hard drive. Please note that digital sources (like SPDIF inputs) are not gain adjustable. Whatever the gain settings that were used initially on this type of source, translates to the gain that you will get when transferring to the hard drive via DCArt10/DC Forensics10. If the original analog to digital transfer was either overloaded or under recorded, it will remain that way during the transfer to your hard drive. Gain corrections (or de-clipping) can be performed at a later time.
5. To commence recording, simply click on the Record button.
6. The "Record Position" is analogous to the tape counter of a conventional tape recorder. It uses real-time measurement. (Minutes: Seconds)
7. To pause the recording, click on the Pause button on the toolbar or in the Record dialog box. You may continue to record from the pause position by repeating the method outlined in step #5.
8. Recording can be terminated by clicking on the Stop button. (Stop is the square button containing a smaller black square within its perimeter).
9. To save your recording, click on the Save button in the "Record File" dialog box. You will notice that a name has already been assigned to your file by the software program. You can either keep the assigned name for your file, or rename it at this time.

Important Note:
DCArt10/DC Forensics10 is compatible with .wav files that were originally created by other programs. It is not necessary to record your .wav files using the Diamond Cut recording routine in order to use the programs processing features.