TIMECODE RECORDING AND PLAYBACK IN
SAMPLITUDE STUDIO 4.05 (WIN95)

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

This application note describes how we recorded 16 channels in Samplitude Studio, 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.
 

EQUIPMENT USED

Hardware	Software
Pentium-II 300MHz  ASUS P2L97 AGP motherboard  Matrox Millenium II AGP Powerdesk graphics card 384MB RAM  Adaptec AHA-2940U/AHA-2940UW PCI SCSI controller  4.5GB Seagate Cheetah 4LP SCSI hard drive STUDI/O STUDI/O Sync Backplate 2xADAT XT  MOTU Pocket Express (not used for this)	Windows 95 B Samplitude Studio 4.05  Sonorus 1.33 drivers  Virtual Memory On (or Off) Graphics Acceleration Full (or OFF)

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!

The first thing to do is to choose 'New Multitrack Project,' the first option under the 'File' menu.  Here you can define the number of tracks and the units of measurement, as well as give your project a name. 

Once you have your tracks up, you need to specify the inputs and outputs.  You get to this window by clicking the '?' button on each track.  We used the monitor out in our example, but you can also use the individual channel outputs.  Remember that Input & Output #1 apply to to Tracks 1 and 2 since we're recording the left and right channels in stereo, so you only have to do this to every odd track (i.e., Tracks 1 & 2 are set to Input #1, Tracks 3 & 4 are set to Input #2, etc.). 

In the Sync window (reached by typing the letter 'G' after your Multitrack Project is active) be sure to enable the SMPTE/MTC Input (setting  it to the STUDI/O MTC in) and enter the SMPTE offset (where the song starts on tape).  Also make sure the frame rate is set to 30fps/non-drop, as that is the rate the Sync Backplate uses.  For other sync devices, set the frame rate accordingly.  Lastly, since we're sample-locked to the ADATs via the STUDI/O's optical inputs, make sure Chase Lock Sync is NOT active.  This feature of Samplitude will speed up and slow down the audio playback to follow incoming timecode: but since we're already sample-locked to the ADATs, which are also the timecode source, we don't need this.  In fact it is desirable to use this feature only when locking to analog tape machines and using A/D/A converter boxes with STUDI/O.

By typing 'Y' you get to this important window, where the buffer settings can be changed. The buffer settings that are ideal for recording will vary from computer to computer.  If you're having dropouts in audio, changing the buffer settings is a good place to start rectifying.  We've used the default settings since they worked fine for us.  This is also where you tell Samplitude where to save all your files.  Make sure this is pointing to the drive and directory where you want your audio recorded!

The play parameters window (reached by typing 'P') is where you set the sample rate for playback.  We set it to 48KHz, the rate at which our ADAT project runs.  Also here is the device used for playback timing, and soundfile edit monitoring.  Make sure it's some STUDI/O device (and not another sound card, if you have one in your system).  Samplitude watches this device to decide where it is in the project, which sample to play out, etc.

Fig. 7 shows the record parameters window (reached by pressing the 'R' key).  Here you declare your recording sample rate (again 48KHz in our case), as well as the record timing device (and record device for non-multidevice recording).  Make sure it's some STUDI/O device (and not another sound card, if you have one in your system).  For multi-device recording, the device used is the one specified in the track setup above.  Also, you can set up 'Playback while Recording' here, to do overdubs.

Once this is all done, just roll the tape back to a point before the SMPTE offset, hit the Record Multiple Files button in the taskbar (shown below), press play on your master ADAT and you'll be recording!

Watch the error display in the lower right hand corner of Samplitude's main window:  this will tell you if you had any buffer overruns or other errors while recording.  If you do have errors, that means all of your audio probably wasn't recorded, some chunks may have been dropped on the way to the disk.  Perhaps you're overtaxing your machine.  Start with fewer channels and try to get an error free recording, and work your way up.

Here are some handy links for more information and applications of Samplitude:

• Official SEK'D application notes
• SEK'D FAQ's and Newsgroup
• Official User's Site has moved..... we are trying to locate it.
• Samplitude User's email discussion list

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.

Macintosh is a trademark of Apple Computers, Inc. Windows 95, Windows MM System are trademarks of Microsoft Inc. Studi/o is a trademark of Sonorus, Inc. Copyright © 1997 Sonorus, Inc. All rights reserved