There are a multitude of free VST and DX plugins available - doing a Google search for "VST plugin" will reveal hundreds of plugin instruments and effects, many of which are free. Some are far better than others and I am in no position to recommend particular ones. However, there are a number of free plugins which I have found especially useful. Some of these are listed below:

You will find links to a number of highly-regarded freeware plugin instruments and effects at:

Cdxtract (
www.cdxtract.com) allows you to covert between different sampler formats. Some conversions work better than others but I have found that the software can generally convert successfully between SF2 and Gigastudio formats. There is a free demo version available - the main limitation of this is that it will only convert the first preset of any file, which is annoying if your file contains a number of different ones! The full version retails for over $100.

The Sfz free soundfont player can be downloaded from Cakewalk's Project 5 website
here. This is a very stable player with the capability to read soundfonts by direct from disk streaming without fully importing them. This means it is capable of playing very large files when the DFD feature is used. It is a VST instrument and will therefore work in most of the common software sequencers (it is included in Sonar). The main drawbacks to this player are the lack of an amplifier and no control over the ADSR (attack, delay, sustain, release) envelope. The latter means that soundfonts may not play with sufficient release for certain applications, whilst they may play with too much for others. This is especially true for guitar sounds, where the level of release required is dependent on the style of playing. However, the Sfz+ player, which costs just $60 for direct download from Cakewalk's website, has both an amplifier and ADSR adjustment, in addition to all the features of the free player. The player also includes stereo chorus and reverb as well as other features generally only found in far more expensive samplers. Therefore, if you simply require a quality player for your sounds, you are unlikely to find anything better than the Sfz+ player. If you want to edit sounds or create new ones of your own, you will require one of the more expensive software samplers such as Halion, Kontakt or VSampler.

Another free soundfont player is Synthfont (
www.synthfont.com). This, like Sfz, is a VST instrument. In my experience, it is rather less stable than Sfz and again does not support ADSR adjustments, but it is certainly worth a try.

The "Classic" range of 9 VST plugins can be downloaded for free from:
http://www.kjaerhusaudio.com/classic-series.php. The collection includes reverb, chorus, phaser, flanger, EQ, compressor, master limiter, delay and auto filter. These are excellent sound-shaping plugins with a warm analog sound.

www.silverspike.com you will find some useful freeware VST plugins, including "Room Machine", which simulates the ambience of virtual rooms and "Ruby Tube", which can add warmth to acoustic sounds. You can also purchase the highly regarded Silverspike reverb.

There are a number of quality free VST sound-shaping plugins for electric guitar available at:
http://www.simulanalog.org/guitarsuite.htm. These include reproductions of 2 classic valve guitar amplifiers - the Fender Twin and the Marshall JCM900. There are also fuzz plugins, a "tube screamer", a phaser and modulation effects. These amp simulations were created as part of a research project and are very good indeed (there are demos at the site which confirm this).

Fretted Synth Audio (
www.frettedsynth.com) have created a range of free VST plugin guitar and bass amp/speaker simulations as well as a variety of other plugin effects. The amp sim presently being offered for download is "Free Amp version 3.5", which offers several different tube amp sounds, ranging from clean to heavily overdriven, a speaker simulation and several stomp-box type effects. These sounds may not authentically model any particular amplifier, but they do sound good!

Read the next page about guitar amp simulation software to see how the excellent free Simulanalog and Fretted Synth plugins compare with the expensive proprietary brands. There are also some demo sound tracks created with the various plugins.