Low latency operation with Sonar™ in Windows 2000/Windows XP
Note: Although the graphics in this guide refer to the Direct Pro 24/96,
the information applies to all of our PCI products (Direct
Pro Q10, Direct Pro LX6, Aark 24, 20/20+ and 20/20)
To achieve Low Latency performance, Aardvark uses custom A|WDM technology.
To use A|WDM, you must instruct SONAR to use MME drivers, instead of WDM.
A|WDM circumvents many of WDM’s limitations, providing lower latency
and increased stability.
CONFIGURING SONAR.
First, go to OPTIONS | AUDIO | ADVANCED (tab) and be sure there is a
checkmark in “Always use MME interface, even when WDM drivers are
available”. If not, do so now, then close and re-open Sonar.
Once you return to Sonar, go to OPTIONS | AUDIO | DRIVER PROFILES (tab)
Make sure the “Show Profile For” menu is set to your Aardvark
Soundcard.
Under “DMA Buffer sizes, set all sizes to “48”. Click
OK, exit Sonar again, then return to the program.
Next, go to OPTIONS | AUDIO | GENERAL (tab)
Latency is adjustable at the bottom of this page. In most cases, there
is no reason to have more than 2 buffers in the playback queue. The “Buffer
size” slider allows you to adjust latency. If your latency is too
low, you may encounter glitches and dropouts in your audio, or it may
not play at all. The lowest possible latency/buffer size is determined
by your PC performance and setup. A little bit of trial an error will
help you determine the ideal buffer setting for stable low-latency performance.
TAKING ADVANTAGE OF OUR LOW LATENCY A|WDM
DRIVERS:
Low latency drivers provide two significant features:
Real time monitoring of inputs with plugin effects
Real time DXI operation
MONITORING INPUTS WITH EFFECTS:
First, Enable input monitoring in Sonar. This is done by going to OPTIONS
| AUDIO | INPUT MONITORING (tab), and choosing the inputs you would like
to monitor w/effects.
Next, Disable Direct Monitoring in your Aardvark software. With the Direct
Pro 24/96, go to PATCHBAY and connect “Playback 1,2” to all
three outputs on the right.
Now, you’ll only be able to hear the input signal if a track is
armed for recording in SONAR.
To do this with the Q10, go to ROUTING. Assuming you are listening though
the Monitor L/R outputs or the Headphone output, use the dropdown menus
to assign “PLAYBACK 1” to the L output, and “PLAYBACK
2” to the R output.
Now, in Sonar, Arm a new track for recording. Set the IN menu to whatever
input you want to record, and set the OUT to “Playback 1,2”
of the Aardvark product you are using. You should now be able to hear
the incoming signal. If you add plugin effects to this track, you will
be able to hear them in real time, even on input.
TO USE DIRECT X INSTRUMENTS (DXI):
Direct X instruments require two tracks, one audio and one MIDI.
First, select an audio track.
In the OUT menu for that track, and Choose “Playback 1,2”
of the Aardvark device you are using.
Next, right-click the FX menu for that track, and choose a DXI you would
like to use from the DirectX instruments menu. Here, I’ve chosen
the DreamStation.
Now, select a MIDI track and choose your DXI (in this case, DreamStation)
in the OUT menu. This MIDI track will now control the DX instrument. The
Aardvark A|WDM drivers will see to it that you hear this instrument as
soon as you hit a note!
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