TIMECODE RECORDING AND PLAYBACK USING
COOL EDIT PRO 1.1 AND THE STUDI/O SYNC BACKPLATE  

Fig. 1 - 16-channel audio recording, recorded from ADAT locked to computer.  

This application note describes how we recorded 16 channels in Cool Edit Pro 1.1, synchronized to two ADATs via the Studi/o Sync Backplate. Timecode recording is when you have the computer following the ADAT tape so that it records and plays back in perfect synchronization (lock step) with the tape.

With this setup we were able to record 16 channels from the two ADAT XT's into the computer locked to timecode.  Then, we listened back to the recorded tracks, and the ADATs at the same time to make sure they were sync'd, and they were, over the whole 6 minute song!

Here are the pertinent setup screens in Cool Edit Pro:
 
Fig. 2 - System Settings Window.

First, let adjust all the settings to optimize recording.  Hitting 'F4' will bring up the Settings Window, and clicking on one of the 'tabs' will get you to that menu (if you want the System menu, click on 'System,' etc.).  Four of the eight settings menus are directly applicable towards recording; the other four may indirectly affect recording performance by utilizing the computer's resources.  Keep in mind that these were the settings that worked for us, and it's entirely possible that you may need to adjust these so Cool Edit Pro will behave properly for you.

The System Settings window (shown above) is very important - this is where you can make some basic adjustments in your computer's memory usage that can have direct effects on the performance of Cool Edit Pro.

The Play/Record Buffer is used to prevent skips and dropouts, with the Total Buffer Size representing how much memory is allocated for playback and recording while the number of buffers multiplies the specified memory allocation.

The Wave Cache Size is the data buffer used for drawing waveforms.  Our cache size is higher than recommended, but it really helped us to record 16 tracks well.  Notice that we are not using the System cache: Cool Edit Pro's cache is optimized for audio.  Also we used asynchronous access: this allows Cool Edit Pro to continue doing its thing while the disk drivers fetch your audio.  You can also designate the temporary recording directories here, as well as reserve hard drive space for them.

If you have any questions about any other settings, the 'Help' button in the lower right of the window will bring up a menu that will explain each option in an easy, not-too-technical manner.

 

Fig. 3 - Multitrack Settings Window.

The Multitrack Settings allows you to specify the Playback and Recording Buffer sizes.  We're not sure how this relates to the buffers in Figure 2, or why there are two separate ways to do essentially the same thing.  We kept the buffers pretty much the same as in the System Settings window (Fig. 1), but increased the the Recording Buffer Size a tad.  The Background Mixing Priority Level is not terribly relevant to recording - as we'll show you in Figure 16, we'll be pausing it to maximize resources.  The Minimum track height at the bottom is important - when we record, we don't want to see any waves being drawn while recording - drawing waves sucks up a LOT of memory and reduces the number of tracks you can record at a time.

 

Fig. 4 - SMPTE Settings Window.

The SMPTE Settings Window has settings that may need to be changed for your computer to sync perfectly with your ADATs.  The Lead Time is how long the computer needs to 'lock up' with external timecode.  While a lower setting like 200ms means it will lock up faster, a setting like 1000 ms is better to ensure that both computer and ADATs are perfectly in sync.  If you find that there is a consistent difference between SMPTE and audio, adjust the Lag Time a little to prevent it.

 
Fig. 5 - Device Settings Window.

To sync properly, the computer needs to know where the timecode is coming from.  In the Device Settings Window, set MIDI in (Sync/Trigger) to 'STUDI/O #1 MTC In' to let our Sync Backplate be the timecode source (if you're using another sync source, this is where you'd select it).  Waveform Playback and record are basically there to show you all the options.  When you click on the pulldown menu button, you should see all STUDI/O inputs and outputs.  There is no need to 'Limit Playback' at the bottom left - unless you're playing through another card that can only handle 8 or 16 bits (we can do 24 cuz we're cool...).  Adjust for DC on Record just makes makes sure that all the waveforms are centered on Cool Edit Pro's center line; if you don't use this and record with different devices, the waveforms look different, either top-heavy or bottom-heavy.

 
Fig. 6 - General Settings Window.

The General Settings Window, along with the Colors, Spectral and Data Settings Windows that follow do not directly affect recording in Cool Edit Pro;  it is possible that they may indirectly affect recording.  These settings worked fine for us, but again, the ideal settings for you may be different.

 
Fig. 7 - Color Settings Window.  

Fig. 8 - Spectral Settings Window.  

Fig. 9 - Data Settings Window.

 
Fig. 10 - New Multitrack Session Window.

Finally we get to ... more set ups for recording!  Cool Edit Pro opens with a new, empty multitrack window, but if you want to record a new session, just hit Control-N to start a new multitrack session.  This may be a good idea if you want to change the Sample Rate and Bit Resolution than you normally use.  Make sure the sample rate here matches the actual sample rate at which you are recording (if you're not sure, check the measured sample rate in the STUDI/O error/status panel).

 
Fig. 11 - Playback Device Window.

Now we need to set up the playback and record channels for each track.  When the tracks are of a medium size (between very small and extremely large - the  and  buttons in the lower right of the screen adjust the track size), the various track setting buttons and menus are available on the extreme left of the track, as shown here: .  'P' adjusts the pan, with -100 being hard left and +100 being hard right; 'V' represents a volume fader, with 0.0 being Unity Gain.  Double-clicking on either one will allow you to adjust them graphically.  The light green button is 'Mute,' the yellow button is 'Solo,' and the red button is 'Record Enable' - the last one we see again in Figure 13.

If you want to isolate your tracks on their own individual outputs, you'll need to assign pairs of tracks to the same Stereo Out and then pan them hard left and hard right.

The two buttons in the middle with numbers represent the playback and record device for that track.  Clicking the top button, with the blue number, pulls up the Playback Device Window where you choose where the track is going to play out of.  In a convenient feature, you can select 'Same for All Tracks' if you want to monitor everything through the STUDI/O Monitor Out.

Fig. 12 - Recording Device Window.

Clicking the lower of the two buttons, with the red number, pulls up the Recording Device Window.  We recommend using the STUDI/O as 8 stereo devices rather than 16 mono devices;  this seems to much more agreeable to most recording software, Cool Edit Pro included.  Since they are stereo devices, you must choose either left or right as a channel along with the Stereo Input number.  In recording 16 tracks, we set Track One to record STUDI/O Stereo In(01) Left Channel, Track Two to record STUDI/O Stereo In(01) Right Channel, Track Three to record STUDI/O Stereo In(02) Left Channel, Track Four to record STUDI/O Stereo In(02) Right Channel, and so forth all the way down to Track 16 (STUDI/O Stereo In(08) Right Channel).

Fig. 13 - Record Enabling Tracks.

Next, tracks have to be Record Enabled - do this by clicking on the Red button to the left of the tracks, and it will turn a bright red.  In Figure 13, we have record enabled Tracks 1-4; Tracks 5 and 6 have not been record enabled.  To record 16 tracks, you must record enable all of them!

 
Fig. 14 - Multitrack Session Information Window.

Hitting Control-I brings up the Multitrack Session Information Window.  Here you can set the SMPTE Offset - also known as the start time of the song on the ADAT.  You probably want to set it a a few seconds before the actual audio begins to make sure the beginning of the audio is not missed.

 
Fig. 15 - Recording with the Smallest Track Sizes.

Next, use the  button in the lower right of the screen to shrink the tracks as much as possible.  Cool Edit Pro will not record 16 tracks accurately if waveforms are drawn while recording!  (At least not on our machine...) Drawing waveforms takes up a LOT of the computer's resources, and can cause inaccurate recording and dropouts.  So be sure to have the tracks as small as possible during recording.  When recording begins, basically as soon as Cool Edit Pro receives timecode, it will draw brown boxes at the beginning of each track.  These boxes will be periodically extended as recording continues.  If you notice when the boxes are extended that perhaps one has not been extended, you've had a dropout.

   
Fig. 16 - Waveforms List Window.

It's important to make sure that the Waveforms list is empty before recording (pull it up by hitting F9).  It shows all the waveforms that have been recorded that have not been completely deleted from memory.  Even if you select a waveform and hit Delete in the Multitrack Window (the main view), it isn't deleted until you Close the wave in the Waveforms List.  Before recording, select all waves and click on the Close Wave button.  You will prompted to save or delete every single wave with the window seen in Figure 19.  If you don't delete and close all waves before recording, when it comes time to save you will have to look at each waveform you recorded and make sure you save that one and not the others.  Saving unused waveforms will quickly take up the available space on your hard, so delete and close waveforms before recording!

 
Fig. 17 - Options Menu.

Finally - the last step before recording!  In the Options pulldown menu, activate 'SMPTE Slave enable' to get Cool Edit Pro ready to sync with timecode, and also enable 'Pause Background Mixing' to prevent Cool Edit Pro from chewing up valuable CPU time while recording.  In fact, we'll leave it off even for playback, since you don't need it at all when you have a fast computer and STUDI/O.

Now you're ready to record - roll the ADAT back to a point before the SMPTE offset, hit Play on the master ADAT and Cool Edit Pro will record in sync!  When recording is completed, hit the stop button  on the transport (all of the other transport buttons are grayed out when Cool Edit Pro is SMPTE Slave enabled; hitting Stop re-enables them), stop the tape and rewind Cool Edit Pro  and play  the recording.

Now sometimes, Cool Edit Pro only plays back only 20-25 seconds at a time.  This occurs when waveform sizes are about an inch long or more during playback.  Cool Edit Pro stops playing because it has to use memory to constantly redraw the waveforms when the cursor gets to the end (the right) of the screen and moves on to the next part of the audio file.  To prevent this, use the Zoom Out Full button  located in the set of 6 buttons to the right of the transport.  This will fit the whole song onto the screen, eliminating the need for redrawing.  This is good if you just want to listen to the whole song uninterrupted.  If you're editing, you'll want to zoom in as much as necessary to make the right cuts.

   
Fig. 18 - Save a Multitrack Session Window.

After recording, you'll want to save you work.  In the File pulldown menu, choose 'Save Session As' if you haven't named your session yet.  Here you can name a session and choose where it will be saved on the hard drive.  The New Folder button  lets you create a new file for the session, so you don't get confused when you have a lot of audio tracks lying around.  When you hit OK, you'll see Figure 18 (below) to save your track changes.

   
Fig. 19 - Saving Track Changes Window.

The Saving Track Changes Window will prompt you to save every single track recorded (plus any spare tracks you had in the waveforms list -- see figure 16).

     
Fig. 20 - Audio System Setup Window.

When saving the waveforms, you can direct them to be saved wherever you want, especially if you want to save the waveforms to a different drive and/or folder than the session.   You can also rename the tracks if you want.

   
Fig. 21 - Saving Wave Data Window.

Lastly, the Saving Wave Data window appears for every wave being saved.  After Track 1 is saved, the Saving Track Changes Window (Fig. 19) comes up for Track 2, etc.  

•   Thanks to John Griggs for helping us with this app note (read John's response HERE).  Here's some useful links:  

  Pixelite Cool Edit Forum http://www.pixelite.com/windaw/forum_main_frame_syn.html Syntrillium Tech Support http://support.syntrillium.com/search.htm

Keep in mind, that these are the settings that we used to get this setup working. Your mileage may vary.

Questions? Comments? Email us at techsup@sonorus.com.

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