SYNCRONIZED RECORD/PLAYBACK OF 24 CHANNELS AT 24 BITS IN DIGITAL PERFORMER USING 2 STUDI/O CARDS
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Before we started the test, we set our audio drive up for optimal performance. This involved setting the 'Video Buffer Settings' mode of our Adaptec card to 'Cache Line' via the PowerDomain Control 4.0 software:
That ensures the SCSI card doesn't hog the PCI bus, leaving no room for audio buffers to/from Studi/o.
Next, since our Tomohawk drive had been formatted with ATTO's ExpressPro-Tools software, we ran that, and made sure the Mode Pages of the drive were optimized for 'Video'. This setting is good for any streaming media, like audio:
Now, we're ready to tackle our real task!
First, we dragged our ASIOs into the ASIO Drivers folder located with the DIgital Performer program itself. For some reason, it's necessary to include the ASIO Soundmanager driver as well (you can get this from the demo copy of Cubase included on the STUDI/O CDROM).
Next, we run DP and set up a project, which you see at the top of the page (click for 1:1 view). We need to set up our audio driver first:
For this test we select the basic ADAT driver, giving two ADAT interfaces per STUDI/O. As you can see our tape is running at 48KHz, and we're locking to optical input A which is connected to the first ADAT machine in the chain. When we click the "Configure Driver" button we get our ASIO Control Panel:
Here we can set the latency of our driver (we're really pushing our machine with 24 tracks, so we've set the latency as high as it goes to give the CPU as much breathing room as possible). Also we can set the bit depth between STUDI/O and DP (note, this does not affect the file format), and our analog output monitor level. Processor cache mode is a future feature of the Mac OS, and the Sync Backplate options are for ASIO-2, which this version of DP does not support.
Speaking of bit depth, we can set the "sample format" in DP next:
This gives us 24 bit sound files, so it's a good thing we have over 2GB of free space for this song!
The last bit of tweeking is to set up our project size, in the "Studio Configuration" window:
We're not actually using 32 inputs or 16 busses, but that's the max you get with 2 STUDI/O cards (actually, if you pick ADAT+mon you get 18 output busses). We found for this particular test that turning the Disk read/write and Buffer sizes down to 192 from the defaults actually improved performance. These parameters will undoubtedly change depending on what you're doing: you may need to increase them during mixdown to get better plug-in performance, etc. Defiinitely, experiment with these -- but save often!
Next, we'll set up our synchronization for the ADATs. Since ASIO2 isn't supported we'll use MIDI Timecode. Our trusty JL Cooper dataMASTER comes in handy here, translating between ADAT and MIDI sync formats. Since we don't have a USB MIDI interface yet, we got GeeThree's Stealth serial port, and used an old standard MIDI interface we had lying around. Setting up FreeMIDI to recognize the ADATs was easy:
Note we called them XT's instead of XT20's -- all Alesis ADATs use the same control codes, so it doesn't matter. Then we just had to set our SMPTE start time in DP and enable MMC:
Now we are ready to record. First we record-enable our channels:
Then we set DP to punch in at the beginning of the song (this part is optional):
Then we turn to the "Audio Monitor" window, where we can check our audio file destinations, and monitor the actual recording:
Time to roll tape! Thanks to MMC, we just rewind in performer, which locates us to the right tape time, and then hit record. That punches us in, and we're rolling. Once done, we can check our sound files in the Soundbytes window:
Our Yosemite couldn't go much beyond 24 tracks, but that's still enough for most projects!
Download the project template for this experiment here: skoota24bit.sit
