ASIO (Audio Stream In Out) protocol, which allows high speed communication between compliant software platforms and ASIO compliant Sound Cards, was designed by Steinberg to reduce or address latency issues with regards to recording onto PCs. This was a significant step in the development of Virtual Studio Technology (hence the name Cubase VST) and furthered the standing of the Cubase software recording platform as a market leader.
Prior to the advent of Cubase VST and the ASIO protocol the issue of Latency, which is basically the audible delay one encounters when monitoring the output from any software based recording package against input, placed significant constraints upon computer recording systems. Since delay, or latency, times were anything up to around 0.75 second and this problem was also compounded by internal timing issues, namely drifting, which made the whole issue of recording in time on computers rather challenging.
With the advent of the ASIO protocol and ASIO compliant sound cards, or audio interfaces, all the issues raised above were effectively addressed, with the removal of drifting problems and latency times significantly reduced. For example, latency times for firewire or PCI sound cards on a modern PC are typically around 0.002 to 0.004 sec., which is pretty much upon the limit of human detection. Note that for comparison, any hardware keyboard workstation or synthesizer has an associated latency, typically around 0.002 second.
Therefore, if recording on a computer, or using soft or virtual synths it is a requirement to use ASIO compliant sound cards, or audio interfaces with ASIO compliant software. Note that recent changes to Apple’s operating system, the advent of OSX onwards, resulted in the implementation of a protocol called audio units, which eliminates latency on Macs for audio unit compliant devices.
For reference, most music production based software developers, e.g. Steinberg & Native Instruments, support ASIO on PC and Audio Units on Mac. Whereas specific music-production sound card and audio interface manufacturers, e.g. EMU (PC only), Presonus, Focusrite, Tascam & Yamaha, also support ASIO & Audio Units. In practice, if you encounter significant latency issues either the incorrect driver has been selected (refer to blog on setting up Cubase), or you are using a sound card that is not ASIO compliant.
favorited this one, man