APPLIED ACOUSTICS SYSTEMS ULTRA ANALOG Manual de usuario descargar pdf (Pagina 55)

6.3 Latency Settings 55

6.2.7 MIDI Program Changes

MIDI program changes can be used to switch between programs while playing. Ultra Analog

VA will change the number of the current program used by the synthesis engine to the number

corresponding to the MIDI program change received by the application.

6.3 Latency Settings

The latency is the time delay between the moment you send a control signal to your computer (for

example when you hit a key on your MIDI keyboard) and the moment when you hear the effect.

Roughly, the latency will be equal to the duration of the buffers used by the application and the

sound card to play audio and MIDI. To calculate the total time required to play a buffer, just divide

the number of samples per buffer by the sampling frequency. For example, 256 samples played

at 48 kHz represent a time of 5.3 ms. Doubling the number of samples and keeping the sampling

frequency constant will double this time while changing the sampling frequency to 96 kHz and

keeping the buffer size constant will reduce the latency to 2.7 ms.

It is of course desirable to have as little latency as possible. Ultra Analog VA however requires

a certain amount of time to be able to calculate sound samples in a continuous manner. This time

depends on the power of your computer, the preset played, the sampling rate, and the number of

voices of polyphony used. Note that it will literally take twice as much CPU power to process

audio at a sampling rate of 96 kHz as it would to process the same data at 48 kHz, simply because

you need to calculate twice as many samples in the same amount of time.

Depending on your machine you should choose, for a given sampling frequency, the smallest

buffer size that allows you to keep real-time for a reasonable number of voices of polyphony. To

adjust these parameters:

• Launch the Audio Control Panel

• Choose the sampling frequency and the audio format (16, 24, 32 bits)

• Adjust the buffer size

Note that this might not be possible on Mac OS or with ASIO drivers on Windows.

In order to optimize the resources allocated to the calculation of audio by Ultra Analog VA, it

is possible to decrease the ratio of resources devoted to the calculation of graphics for the inter-

face in favor of audio related calculations. To adjust this ratio, choose the Preferences command

under the Edit menu and adjust the Performance slider to the desired value between better au-

dio performance and smoother graphics. This setting may have little noticeable effect on recent

computers.

1 2 ... 50 51 52 53 54 55 56 57 58 59 60 ... 69 70

Sin comentarios

APPLIED ACOUSTICS SYSTEMS ULTRA ANALOG Manual de usuario Pagina 55