Specifications

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Using the DirectX driver
Cubase VST supports DirectX, or to be more precise, DirectX, which is a part of
the Microsoft DirectX Foundation package. This means that if your audio card
comes with a native DirectX driver, you can use this instead of the Windows Multi-
media system to play back audio. This has some benefits (mainly lower latency
times and the ability to play back audio from several applications simultaneously)
but also some restrictions (mainly audio output only - no input). For details, see
page 379.
Simultaneous Recording and Playback - “Full Duplex”
On a regular multi track recorder you often perform something called overdubbing.
This is when you listen to one Track and at the same time record on another.
You can of course overdub in Cubase VST, but there are a few things you have to be
aware of.
For a PC audio card to allow simultaneous recording and playback, the card must
support something called “Full Duplex”. Some PC audio cards do not have this
ability. This means that as soon as you enter record mode, you will not hear your
previously recorded audio Tracks. This is not a limitation of Cubase VST, but of the
cards themselves.
If your card does have the ability to record and play back at the same time you
should activate this function in ASIO Multimedia Setup, see page 369.
It is of course a great benefit to have this functionality, since it allows you to match
your current performance to the previous audio recordings, for example when add-
ing vocal harmonies, one by one.
Some cards, like the Roland RAP-10, have the ability to use one channel for play-
back and the other for recording, which means that you can record and play back
audio at the same time, but only if playback is limited to mono. Some cards can
play back and record audio at the same time, but with reduced audio quality of the
playback signal (usually 8 bit resolution instead of 16 bit). If this is the case with
your audio card (see its documentation), make sure to deactivate all audio inputs
when you want to listen to your recordings with full audio quality.
Multiple Cards
If you have multiple cards you can theoretically select one for input and another for
output. However, this is not recommended unless the cards are tied together with a
word clock sync signal. The sample rate clocks in any two cards will always drift
slightly against each other, which can cause glitches and dropouts in the audio.