The various parts of a sound card

When composing, as well as playing music, the sound quality is of course very important. Let us remind that in the MIDI world (Musical Instrument Digital Interface), the sound quality is something which is not dealt with at all.

Indeed, when a note is sent through MIDI by a music software, it is only an instruction of the type “Play a C # note, with an average force, during X seconds, with a sound of trumpet”. The sound quality of the trumpet entirely depends upon the synthesizer receiving the MIDI instruction, but not at all upon the software which sent it. This synthesizer may be the one integrated in your sound card or an external synthesizer connected to your computer.

On this subject, it is useful to remind that on most sound cards, there are two distinct parts, often confused in their functions. The first part – used by most multimedia and didactic software – is the audio part. It makes it possible to read sound files of the type “wav”, “mp3”,… As such a file contains all information about the sound to play, the card can thus read this file and make it into sounds. It is also this part of the card that generates the sound warnings of Windows. This function of the card is usually automatically configured with the installation of Windows.

The other function of a sound card is the synthesizer. There are sometimes several different synthesizers according to the sound card. This module receives MIDI information and transforms them into sounds. This module is used by a MIDI software and also makes it possible to read MIDI files (.mid). The quality of the generated sounds is then directly dependent upon the quality of this synthesizer module. In other words, a $25 sound card will be much worse than an external $2,500 synthesizer! There lies the difference and one can find a large range of various sound qualities. Moreover, the taste also intervenes, the banks of sounds also having aesthetic characteristics appreciated by some and not by others, for the same price.

Thus we have two parts in the sound card : the reading of existing sounds and the sound synthesis. A sound card may contain several modules of each kind. Those two modules are electronic systems integrated in your sound card.

In addition to these electronic modules, we often find a software synthesizer. The principle is the same as the electronic synthesizer, but the sound creation is done by software, using the processor computing speed and no more by the electronic devices of the card. For a music software, this type of synthesizer is seen as a MIDI output to which MIDI instructions may be sent to play a musical score. This synthesizer computes the sound in real time and sends it to the first part of the card, as seen here above: the one that simply plays an existing sound. Therefore, a low quality sound card with a very bad synthesizer may play very nice sounds when combined to a software synthesizer playing the sounds on the audio part of the card.

Some information on how sounds are created. The first synthesizers used mathematical computing methods of the sound harmonics and could influence the sonority and the way it evolved with time. Those methods use the properties of electronic devices. It was the era of “analog” synthesizers, which contributed very much to the richness of electronic instruments. Those electronic systems are now simulated by software, with a much greater flexibility because you just need to change the software, no more the electronic devices of the card.

The other method is to use a sample table. The idea is to have real sounds in memory, recorded for each instrument : a real trumpet note is recorded and saved in a file, and this for each instrument. When the synthesizer receives a MIDI instruction to play an organ note, it finds the sample of the organ note, modifies it to adapt its pitch and velocity and then combines it with the other playing notes (mixing), because at the same time there may be notes playing with other instruments, as in an orchestration. Depending on the samples quality, we get much better sound quality, at least for natural instruments. The requested quality may go as far as sampling each note of a real piano, each with various velocity levels (speed of hitting the note) and in a CD sound quality or even more. Therefore, the sampling information quantity to treat may become very high and it is common for professional samplers to deal with hundreds of megabytes of samples. One can then reach an almost perfect quality in the reproduction of natural instruments, but one needs to pay the price for it. However, even basic samplers produce quite satisfactory sound results.

This sampling method may be implemented in two ways : by an electronic system present on the sound card or by a sampling software, often called “virtual sampler”. You can load sound samples banks into it and this sampler then behaves as a MIDI synthesizer to which a music software may send MIDI instructions to play a music score.

What is the optimum solution for composing music ? If you work at home, for you, I would say that any above method is correct, as soon as the sound quality achieves your requirements. However, if you want to easily communicate your music, personalize it, manage and distribute it, I would presently recommend software solutions. To play your compositions, I suggest to use a sampler and for sound creation (synthesis sounds to personalize your compositions), use a synthesis software that can export the sound results as samples to play on the sampler software.

In the field of sound cards and samples, there is a very interesting standard named “SoundFont”. It is like a word processing with which you can write in various text fonts (Arial, Times, Courier,…). Here the “fonts” are sounds, used to perform your music score. These sound banks may be downloaded from numerous Internet sites (some free and some to buy) and it is a method to exchange sounds. By using the same SoundFont banks on various computers and sound cards, you can get the same sound effects, which guaranties the reproduction of your music composition.

Ideally, your sound card should be SoundFont compatible, which is the case in recent SoundBlaster cards, among others. The SoundFont standard evolved from the work of Creative Labs (SoundBlaster cards manufacturer) and Emu (professional synthesizers and samplers manufacturer). Otherwise, you may use a virtual sampler software, but you need a more powerful computer (the exact power needed depends upon the size of the sample files and also the number of simultaneous notes played, be careful for big orchestrations!).

After this theoretical introduction, we will examine practical software solutions so that you can enhance the sound quality of the scores you write with Pizzicato or the playing of your MIDI files.

Let us know of any reactions on this subject, to email address I am listening to you and ready to answer your questions and to help you in this subject!

Dominique Vandenneucker

Designer of Pizzicato.

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