ASIO driver support for Spectrum Lab
Since April 2006, ASIO drivers are supported by Spectrum Lab (besides the standard multimedia interface). The benefit of ASIO drivers is a lower latency time under certain conditions, and -more important- some cards cannot be used in 24-bit / 96 kHz mode through the standard multimedia API.
See also: Audio settings, notes on various soundcards which were tested with SL.
To activate an ASIO driver for Spectrum Lab, open the Audio Settings tab in the configuration dialog. There are two selection lists on the left, labelled "Audio Input Device" and "Audio Output Device". If ASIO drivers are installed on your system, you will find them listed in these combo boxes (below the standard multimedia devices) as in the screenshot below:
Note: Entries beginning with a number are standard multimedia drivers. Entries beginning with a letter are ASIO drivers. If there are no entries in the list which do not begin with number, the program couldn't find any ASIO driver. Most ASIO driver names contain the string "ASIO" so it should be easy to tell them from standard multimedia devices.
You will see the sampling rates supported by the current ASIO driver in the "Sample Rate" combo. If you see no sampling rate listed there at all, the selected input driver cannot be used with Spectrum Lab. If you only see one single sample rate (like 48000 Hz), you will most likely be using one of Creative's poor ASIO drivers ! Skip the next chapter if you do NOT use one of Creative's soundcards...
As you see in the screenshot, the Creative Labs drivers can be very confusing: There is one driver for sampling at 48 kHz, another driver(!) for 96 kHz, and yet another driver for 24 bit resolution at 96 kHz. So in this ugly case, the right driver must be selected manually to use a certain sampling rate. Using 44.1 kHz sampling with any of Creative's ASIO drivers was not possible at all !
For an explanation of these problems (and why Cubase has them too), do a websearch on "Creative ASIO problem". The problems may be fixed by the time you read this, but with my Soundblaster Audigy 2 ZS it was really annoying to be limited to 48000 or 96000 Hz sampling ).
After selecting an ASIO device for input, the usual controls in the soundcard control panel (especially the input channel selection) does not work any longer, because ASIO seems to be cooking its own soup. Instead, the active input channels must be selected by the application. By default, the first (or the first two) inputs are used by Spectrum Lab. But you can select other input channels by clicking on the "Ctrl"-button in the "Audio Input Device" panel:
Clicking on the "Ctrl"-button opens another control panel. For ASIO devices, it looks like this :
For stereo mode, you must select at least two two different input channels. For monophone input, one channel is sufficient. If too few channels are selected, the driver may simply stop, or SpecLab's ASIO wrapper will select an input channel by its own gusto (which is usually not what you want).
A similar selection is possible for output. Please note that the current version of Spectrum Lab does not allow different ASIO drivers for in- and output (because it can only load one ASIO driver at a time, which does the in- and output simultaneously). But it's often possible to use an ASIO driver for input from one soundcard, and use a standard multimedia device to send the output to a different soundcard.
See also: Audio Settings, Spectrum Lab's main index .