User manual ASIO4ALL V2 UNIVERSAL ASIO DRIVER FOR WDM AUDIO

[. . . ] Note that the off-line control panel launcher works like a mini-ASIO-host of its own and does not reflect the current device status of any instance of ASIO4ALL that may be open at the same time!Changes made in the off-line control panel will have an effect only after you restart the audio application. Settings made in the off-line control panel, however, will have no effect at all for applications that have been configured with the ASIO4ALL (on-line) control panel launched from inside the audio options dialog of the application. Once you made it into the ASIO4ALL control panel, you can now proceed with some basic configuration. Basic Configuration Illustration 1: Basic Control Panel View 1. [. . . ] By expanding the device list, you can now fully explore the WDM audio architecture of your system. The device list contains Devices, Device Interfaces and so called "Pins" (this is Microsoft(r) lingo). The figure above illustrates how they interrelate in the WDM KS hierarchy. Using the "Action"-button, you can now selectively enable/disable each particular item in the device list. Multi-device-setups require that all the devices involved are running from the same clock source. Fortunately, most USB devices will automatically syncronize themselves for as long as the host controllers they are connected to have a common clock source, which is trivially true for the USB host controllers embedded in the south bridge on any mainboard. Note: If devices are not accurately synced, their audio streams are likely to drift apart over time!Latency Compensation Since ASIO4ALL does not have sufficient knowledge of the underlying hardware/driver architecture, it can only guess the actual latencies involved. With these sliders you can compensate for the latencies unknown to ASIO4ALL such that recordings in your sequencer Software are properly aligned with the rest. Note: In multi-device-setups the largest respective value of all devices will be used. Therefore, if different devices have different inherent latencies, audio placement will not be accurate for some devices! 2. Hardware Buffer on/off Enables the hardware buffer for the highlighted device. This only works for so called "WavePCI" miniports, as other types of WDM drivers do not usually allow direct access to the hardware buffer. Adjustment for best hardware buffer performance involves the "ASIO Buffer Size" slider and the "Buffer Offset" slider (see below). The biggest advantage of using the hardware buffer is that this method uses a lot less CPU. In multi-device-setups, it is possible to mix Hardware-buffered devices with devices that are not. If hardware buffering is not supported by a particular audio device, there will be an additional latency of a couple hundred milliseconds, which is clearly audible. Kernel Buffers/Buffer Offset If hardware buffering is disabled, this control lets you add up to two more buffers to be queued for audio output. Each additional buffer increases the output latency of the device by the time it takes to play one buffer. Therefore, the initial setting of "2" should only be changed on less powerful machines, where reasonably small ASIO buffer sizes cannot be achieved with the default setting. If hardware buffering is enabled, this control determines the amount of clearance (in ms) between where ASIO4ALL will insert data into/read data from the hardware buffer, and the position where ASIO4ALL currently thinks the hardware read/write position is. As a general rule: Higher settings increase latencies and stability, lower settings have the adverse effect. [. . . ] This makes it possible to have several instances of ASIO4ALL run at the same time for as long as they do not try to use the same piece of audio hardware exclusively. This further allows having ASIO4ALL run in educational/computer lab type environments without "user666" being able to f**** things up for any user on the same machine, with the exception of "user666" him/her/itself. · The latencies displayed in e. g. Cubase SX 3 do not match the values that would result from the ASIO buffer size. ASIO4ALL supports the latency compensation features of ASIO hosts that perform latency compensation. [. . . ]