ASIO Problems

ASIO is only available with SCS Standard and higher license levels.

The troubleshooting information below is only relevant when using the BASS audio library as your Audio Driver.

ASIO support is only available when using the SCS internal mixer, so you may need to go to Permanent Options / General Options, click on the Audio Driver tab and choose Use SCS internal mixer. Leave the various buffering options at the SCS default settings, and make sure the Ignore ASIO checkbox is clear. If you have made any changes to these options, click OK and then close and restart SCS.

Pre-Load Whole Files

If you encounter playback problems with ASIO then this may well be fixed if you pre-load your audio files into memory. SCS can populate the ASIO playback buffer much faster from a file loaded into memory than a file pulled from disk, especially if the file is not in WAV format. When loading a file into memory, SCS stores the file in WAV format, which is the fastest format for populating the ASIO buffers.

To pre-load your audio files into memory, whenever you add an Audio File cue set the checkbox labeled Pre-Load Whole File. For Playlist cues set the checkbox labeled Pre-Load Whole Files.

You can also set or clear this field for all or many cues using Bulk Edit Cues. If you are having playback problems with your ASIO outputs it is recommended you set this field on all cues.

Loading files into memory can take up a lot of memory, especially as they are stored in memory in WAV format. To help prevent an excessive amount of memory being requested by the program, SCS ignores the Pre-Load Whole File flag for files that have a duration greater than 12 minutes. This applies even if you only select a smaller portion of the file to play. There is also a limit to the number of files that will be loaded into memory concurrently. This is set under Permanent Options / General Options, in the field Max. No. of Files to Pre-Load Whole File. The default is 3, but you may set this higher if you have 4 or more files to run back-to-back, or simultaneously. The maximum value is 50. Note that this limit only applies to Audio File cues marked as Pre-Load Whole File that have a file with a duration greater than 6 minutes. The Max. No. of Files to Pre-Load Whole File does not affect Playlist cues as a Playlist only opens two files at a time (one to play or playing, and the next one ready to play).

ASIO Buffer Size

SCS sets the ASIO buffer size to the maximum advised by your sound card's ASIO driver, subject to an overall limit to make sure the buffer size isn't so large that it causes unacceptable delays in level and pan changes, etc. Some sound cards do not allow programs to change the pre-set ASIO buffer size, so it is recommended that you set the buffer size to the maximum setting via the sound card's ASIO control panel. For example, the Dante Virtual Soundcard ASIO driver has an default buffer size of 128 samples. If your sample rate is 48000 samples per second then this provides only about 2.7ms for SCS to populate the ASIO buffer from the internal mixer's output. In the Dante Virtual Soundcard Control Panel you can select other buffer sizes. Select the maximum setting, which is 2048 samples (based on information in the version 3.0.x User Manual).

Important Note about ASIO

If you are using ASIO outputs on your production computer (eg your theatre's PC), make sure you run through your cues on that machine before your first rehearsal, so you can sort out any buffering issues. The settings you may have had on your design computer (if it's not the same computer) may be different to those required on the production computer.

Thanks

Thanks to David Blanchard, Steve Decker and Heather Gallagher for contributions to the above and for ASIO testing in general.