NOTE (Continued)
Two other measurements you need to look out for are signal-to-noise ratio and
frequency response. As with the other measurements mentioned here, the
higher the better. Since all electronic devices produce some amount of noise,
the signal-to-noise ratio of a sound card tells you how much higher the signal
strength is compared to the amount of internal noise made by the sound
card. The bigger the number, the quieter the card. A good signal-to-noise
measurement is about 90 dB or higher. Frequency response is actually a
range of numbers, which is based on the capabilities of human hearing.
The frequency response of human hearing is approximately 20 Hz to 20 kHz.
A good sound card will encompass at least that range, maybe even more.
If you want to purchase a sound card with a built-in MIDI synthesizer, there
are a number of additional features you should know about. Early sound
cards sported synthesizers based on FM (frequency modulation) synthesis.
Unfortunately, this method wasn’t much of a step up from the basic beeps
and boops of a PC speaker. Even though FM works well with organ and bell-
type sounds, it fails miserably when trying to portray any other type of
instrument. Fortunately, today’s sound cards use a technology called
wavetable synthesis. This process can provide some very realistic sounds.
The reason for this realism lies in the fact that a wavetable synthesizer plays
back pre-recorded real-life instruments and sounds. When the synthesizer
receives a MIDI “note-on” message, instead of creating a sound electronically
from scratch (as with FM), it plays back a small digital recording, which can
be anything from the sound of a piano to the effect of ducks quacking. The
only drawback to wavetable synthesis is that the samples need to be kept
small since they are stored in RAM (random access memory) or ROM (read
only memory). Suffice it to say, the bigger the wavetable RAM or ROM your
card comes with, the better. A good number to look for is about 2 MB.
You’ll also want to take into account the degree of playback control over the
wavetable samples that a card provides. All sound cards today support
General MIDI (GM), which is a set of guidelines specifying 128 pre-set sounds
that all GM-compatible synths must have and the memory location (or MIDI
program number) of those sounds. This ensures that if a sound card is told to
play program number 37, it will always call up a slap electric bass sound
rather than a soprano saxophone. Unlike professional synthesizers, however,
GM doesn’t support any kind of sound parameter programming. That’s where
the GS and XG formats come in. The Roland GS format expands on the GM
standard by offering additional sounds along with sound-programming
control over a few synthesis parameters. Yamaha’s XG format goes even
further by requiring three separate effects processors, more than a dozen
programmable synthesis parameters (such as the brightness of a sound), and
more than 100 sets of 128 sounds each. So be sure to get a card that supports
GS, XG, or both.
By following these guidelines, and taking some time to research your
purchase, you should be able to find the right sound card to fit your needs.
Good luck!
http://www.muskalipman.com
30
Getting Started with SONAR — Chapter 2
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comments to this Manuals