SYNCRONIZED RECORD/PLAYBACK OF 16 CHANNELS AT 24 BITS IN CUBASE VST/24 v.4.1 USING STUDI/O AND ASIO-2 DRIVERS
Fig. 1 - 16-channel audio recording, recorded from ADAT locked to computer. The VST Master and Mixer windows are also shown.
This application note describes how we recorded 16 channels in Cubase VST, synchronized to two ADAT XT20s with the JL Cooper dataMASTER II used for machine control, and using our ASIO-2 driver for sample-accurate synchronization. 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.
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Hardware |
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Equipment used.
With this setup we were able to record 16 channels from the two ADAT XT20's into the computer, sample-locked with ASIO-2. 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 4 minute song!
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:
Next, we set our System Cache (in the Memory control panel) low, but not all the way down. We found that 512K was a good setting:
Then we set our monitor to Thousands of colors -- a good compromise between speed and looks:
Before launching Cubase, make sure it has enough memory:
We have 192MB in our machine, so we're giving most of the available (94) to Cubase.
Next we make sure our ASIO2 drivers are in the ASIO folder, which is in with the Cubase VST/24 application:
Now you can run Cubase.... If you see this alert box when booting Cubase:
Don't worry, this is a good thing. This happens when our ASIO being used and the sample rate changed. When you get it on startup, it means that the board has booted up and locked to it's optical inputs (if you have it set up that way... if you're using ADATs, then I hope so!). Now, on to the real setup...
MIDI SETUP
First, for the synchronization of the ADATs without ASIO2, 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. We chose not to use OMS, instead going direct to the serial port:
For ASIO 2 which is supported in VST4.1, we use the Sync Backplate connected to the last ADAT via 9 pin (click here to see how the backplate was installed). These MIDI settings remain the same.
AUDIO SETUP
By clicking on 'System' in the Audio pulldown menu, you get to the Audio System Setup Window. Here you must set the number of channels you want to use in your song. This can be more or less than the number of inputs/outputs you have, and you can always increase it later.
When using ASIO 2 and the Sync Backplate, you must be locking to the ADAT for your clock source. Set Audio Clock Source to Optical A or B.
We selected 'Tape Type' for the Monitoring type, but it's a matter of taste. One note: 'Global Disable' is the most CPU-efficient mode, though you may want to sacrifice some CPU cycles in order to get monitoring through Cubase's VST engine (otherwise, you could use your mixing board if you have one). But keep it in mind if you're trying to record a lot of channels and you're running out of CPU time. Note that we have the 'ASIO Direct Monitor' checked. This actually makes 'Tape Type' just as efficient as 'Global Disable' , since the monitoring is being done by the STUDI/O onboard DSP instead of Cubase. What this means is that you get a very low (3 samples, or about 60 microseconds) latency for monitoring your input, but you also get only the dry input, with no inline VST effects. If you have side-chain effects (for example, from a channel aux send to a reverb), these will still be heard.
If you're having some problems with recording, you may want to tweak the 'Memory per Channel' and 'Disk Block Buffer Size' settings, as well as adjust the latency of our ASIO. Remember, the settings you see are the ones that worked best for us; every computer is different, so they may have to be changed. On our Yosemite, 96KB disk block buffer size seems the best.
Hitting the Launch button from the System control panel (above) brings up this window. Here you can set parameters particular to our ASIO. Note that each of our ASIO's remembers it's settings. Here's an explanation:
SYNC SETUP
In the 'Options' pulldown menu is Synchronization. For any timecode based recording, the synchronization settings must be correct for everything to run smoothly.
For Timecode Base we used 'ASIO2', with a frame rate of 30 frames per second. You can use any frame rate you want. ASIO2 will give you sample accurate lock to the incoming Time Code when the Studio is also getting its master clock from the timecode source, the ADAT. When you roll the ADAT (either from their from its panel, or BRC/LRC, Cubase will follow faithfully (when the SYNC button on the transport bar is lit).
The Song Start is used to set the start time of the song, corresponding to the start time of the song on the ADAT.
We set the MROS resolution as high as it will go. Sure, why not?? This affects how accurately you can edit.
INPUT/OUTPUT BUSS SETUP
The VST Inputs are found in the 'Audio' pulldown menu. Be sure to turn your inputs 'on' by clicking on the green boxes so the turn a nice bright green like you see here. Since the inputs are in stereo, each input represents two channels to record, so turning on 8 will give you sixteen channels of audio. Each pair you activate uses more CPU power, though, so only activate the ones you want to use; and when mixing down, turn them all off to get the most 'horsepower' for your Plug-Ins. You can relabel the inputs to your convenience by clicking on the right-hand labels.
If you use the ASIO ADAT+SPDIF, you'll see only 10 inputs available, with two labeled 'SPDIF'. If you use the ASIO ADAT with two boards, you'll see 32 inputs available, as you see above.
Once your inputs have been activated,
you need to assign them to tracks, and this is done in the VST Mixer
window. This window can be reached by selecting 'Monitor' in
the 'Audio' pulldown menu. Above each channel is the button to
assign the channels. To do this, you must hold down
the 
key
and then click with the mouse to get the pulldown window as shown
above (scroll to the right). If you don't have 16 channels to
choose from, double check the Audio System Setup window and the
Inputs window to make sure everything is configured properly.
You also use the VST Mixer window to steer the tracks to the the output busses. This is useful because each bus can be turned on and off (in the VST Master window, shown below in Figure 7). You can have all the drums on Bus 2 and all the vocals on Bus 3, mute the drums and mix the vocals, making sure the voices are all balanced properly. Or cut the vocals and play the drums in mono to see if they're flamming. You can use the busses to set the master levels of each component of the song. Basically, you can group your sounds together in any way you like. Clicking on the label at the bottom of the channel strip shows a list of the active busses. Inactive busses won't show up in this list, so activate the ones you want to use before trying to assign them.
The VST Master Window, also in the Audio pulldown menu, allows you to determine how many buses are active. Since we have two STUDI/O boards in our Yosemite, we have a total of 16 busses with the Studio-ADAT ASIO device selected. While the Master bus is automatically active, the others can be turned on by clicking on the 'Active' button above the bus so that it turns green. Inactive busses will not show up in the pulldown list in the Monitor window.
RECORD SETUP
Next you have to tell Cubase that you intend to record more than one channel at a time, so in the 'Options' pulldown menu, highlight 'Multirecord' and click on 'Active.' As long as the check mark is there, you're ready to record.
Once that's done, the arrangement window will have an additional column labeled 'R.' You can see this in the screen shot. Clicking on the 'R' column activates that track for recording. The first track you set to record will bring this menu up, and here you tell Cubase where your audio files will be stored.
Finally, here's the way the transport should look. We set up to punch in starting from bar 4. By setting the left locator to 4 (by double-clicking on the Left Locator box and typing 4) and activating the Punch In button to its left, Cubase will start recording at Bar 4. We used 'Replace' as our record mode; it seems to work better than 'Overdub' for us.
Don't forget to set the song tempo by double-clicking on it and typing it in. Finally, make sure the Sync button is activated ('lit') as above. That way, Cubase won't start recording until it gets to the offset point in the timecode. Double-click the stop button (which sends you back to bar one) and hit the record button in Cubase; your ADATs will shuttle back to song start and you'll be recording 16 tracks of audio!
Download a template of this project HERE: test24.sit
For more info and ideas about Cubase VST check out these Cubase sites:
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Keep in mind, that these are the settings that we used to get this setup working. Your mileage may vary.
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
