Audio Engine options

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Hello,
is there any official detailed documentation about the different Audio Engine settings inside the Options window? Thanks.

Hi Mistheria,

There is no one spot where it is all organized but I cobbled together the audio engine options docs in one list from the C3 user guide and the C2 user guide, hope it’s what you needed and that it helps.

Understanding Cantabile’s Multi-Processor Option

During early development of Cantabile’s multi-processor support we noticed that some plugins don’t work
correctly if two instances of the same plugin are processed at the same time. (eg: two instances of the same instrument plugin) For this reason Cantabile has a couple of options (Options -> Audio Engine) that controls multi-processor support. The available options are:

Number of Audio Threads:

Controls the number of threads Cantabile will use to perform audio processing. Normally this should be set to the number of physical processors your machine has. For processors that support hyper-threading it should be the number of actual physically processor cores - not the number of virtual hyper cores. By setting the number of audio threads to 1 you can effectively disable Cantabile’s multi-core support. This mightbe useful if a plugin proves to be completely incompatible with the multiprocessor support. Generally this mode shouldn’t be needed but may be useful for diagnostics reasons (particularly for plugin developers) or for some unique scenarios this might actually provide better performance (eg: when only using a single plugin). By setting this to a number lower than the number of physical processors available you can leave processing power available to other programs, or for plugins that support their own built-in multi-core processing.

Multi-Core Mode:

Compatibility Mode provides significant performance increases when running most multi-rack songs and is the recommended mode for most situations. In this mode racks are processed in parallel but processing will stall if two or more plugins of the same type need to be processed at the same time – in which case they will be processed one after the other. Aggressive Mode is suitable when running many racks with the same plugins on each rack. In this mode the plugins being used must be compatible. Many plugins are compatible with this mode, but those that aren’t can cause undesirable effects ranging from noise to crashing the entire application. When a song contains no duplicate plugins Compatibility Mode and Aggressive Mode are effectively equivalent.

Prevent Memory Paging:

When using large sample based instruments memory paging can have an adverse effect on performance and sometimes lead to audio drop outs. This happens because Windows will sometimes unload sections of memory that it thinks are not actively being used to make room for other programs. For example when a machine is left running but idle overnight Windows will often page out large sections of memory for no apparent reason. When returning to the machine in the morning there can be considerable audio dropouts as each page is memory page read back from disk. Cantabile’s Prevent Memory Page options helps reduce these problems by periodically “touching” each page of memory to let Windows know that it’s still in use (even if it hasn’t been used in a long time). Enabling Memory Paging Options. The options to prevent memory paging are on the Audio Engine options page in the Options dialog.

Sample Rate Conversion Quality:

Specifies the quality level of sample rate conversion when playing audio files with a sample rate different to the current audio driver.

Enable Output Limiter, threshold:

Select this option to enable Cantabile’s output limiter. When selected, audio samples with an amplitude below the threshold are output unaltered. Samples above the threshold however are soft saturated, to not exceed the maximum possible output level. Use the output limiter to avoid hard clipping and distortion that can occur when audio levels exceed peak levels. There is a small performance overhead in using the output limiter. If you don’t need this option, turning it off can save some processing time.

Double precision (64-bit) audio:

These terms refer to the size of a single audio sample - 32 or 64 bits (also called single and double precision) and is related to audio quality. A more precise number (64-bit) obviously allows for a more accurate representation of a sound. That said, 32-bit audio samples are generally more than good enough for nearly all applications and in general you can’t tell the difference between the two formats. One scenario where you might want to use 64-bit audio is when a signal is going to be heavily processed through a long chain of plugins. By using 64-bit audio you can reduce the accumulation of rounding errors that might occur by using a less precise number format. Cantabile supports both 32 and 64 bit audio as a global option - see Options -> Audio Engine -> Double precision (64-bit) audio. Note that not all plugins support 64-bit audio - check the plugin’s documentation.

Dave

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Thanks a lot @dave_dore ! That’s what I was looking for and you have explained it clearly and perfectly!

Btw, I really suggest to include such info inside Cantabile or as separate text file, it really helps on getting the best from Cantabile and, therefore, having more satisfied users… and this is important on the “business/marketing” side… :wink:

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