Incoming audio signals and VST Instruments played via a MIDI keyboard can only be monitored with an noticeable and audible delay.
Every computer based music system needs some time for calculating and generating audio. Most crucial is the period between the moment in which the sequencer (Cubase, Nuendo or Sequel) is passing an audio signal to the audio hardware and the moment in which the signal is actually available at the analog output of the audio interface and thus audible. The consequent delay is referred to as latency and mainly caused by the so called buffer of the audio card driver. Demanding users can be annoyed even by a delay of a few milliseconds, latencies of 20 ms or more are clearly audible to less trained ears.
Dedicated audio interfaces offer the possibility to adjust the latency by changing the buffer size. The bigger the buffer the more time is available for the system to process the signal and the longer is the latency/delay of the signal.
Unfortunately the buffer cannot be set to any desired value. If the buffer is too small the audio card has not enough time for processing the audio signal completely. Crackles and clicks or stuttering playback are typical signs for an overcharged system.
The lowest possible latency depends on many factors, particularly on the audio interface, the corresponding driver and the general performance of the computer. The respective application also plays a decisive role. For example, elaborate tasks like the calculation of demanding effects or the usage of complex virtual synthesizers ask for higher latencies than the basic playback of audio files.
Adjusting latency under macOS
Under Mac OS X the buffer/latency can be adjusted in the respective application.
- Cubase and Nuendo: In Cubase and Nuendo the latency of the audio interface can be set in the dialog "Device Setup" ("Devices > Device Setup..."). Depending on the program version you'll find the entry of your audio interface in the "Devices" list under "Multitrack", "VST Audiobay" or "VST Audio System". Here you can enter the buffer size directly or, after clicking the "Settings..." button or the audio hardware entry -> "Control Panel", in another dialog window. Refer to the operation manual of your Cubase/Nuendo version for further details.
- Sequel: In order to change the latency/buffer in Sequel open the "Program Settings Page" (lowest Symbol in the Multi Zone). Under "Audio Connection" click on "Setup...". A pop-up window opens in which the buffer size can be set.
Adjusting latency under Windows
Under Windows the buffer/latency setting can be made in the control panel of the ASIO driver of the audio card. The audio card settings can be accessed in the Start menu under "(All) Programs" or via a corresponding symbol in the Quick Launch Bar of Windows. Refer to the manual of your audio interface for further details.
- Cubase and Nuendo: In Cubase/Nuendo the control panel of the ASIO driver can also be accessed in the "Device Setup" dialog ("Devices > Device Setup..."). Depending on the program version you'll find the entry of your audio interface in the "Devices" list under "Multitrack", "VST Audiobay" or "VST Audiosystem". A click on the "Settings..." button or the audio hardware entry > "Control Panel" opens the control panel of the active ASIO driver. Refer to the operation manual of your Cubase/Nuendo version for further details.
- Sequel: In Sequel you can also access the control panel of the ASIO driver via "Program Settings Page" (lowest Symbol in the Multi Zone) > Audio Connection > Settings...".
Using simple soundcards and on-board soundchips under Windows
Please note that simple soundcards or on-board soundchips without ASIO driver support do not allow the adjustment of the latency.
The universal ASIO driver "ASIO4ALL" from Michael Tippach might be a possible solution. It is available for free on www.asio4all.com. But, of course, since it cannot change the rather low sound quality (high noise level, non-linear frequency response, bad electrostatic shield) and the substandard AD/DA converters of many soundcards and onboard soundchips it should rather be considered as a workaround. For professional audio software dedicated audio interfaces with ASIO driver support should be preferred.