MTSoftware has posted free VST software for Mac OS X: HostX, a VSTi host application; TsampX, a standalone sampler for OS X; and TdrumX, a standalone drum machine). A spectral filter patch for Max/MSP, "Turn to FFT" is also available for download.

Crossfade Loop Synth is a simple AU instrument - it loads a sample from disk (in AIFF, SD2 or WAV format) and plays it back in the classic sampler way -- i.e., higher notes get shorter, lower notes longer. This new version 1.2 fixes some bugs and adds support for wav. and SDII files. LoopSynth is available for download and is a donationware.

Rayverb by Prosoniq is an inverse retraycing reverb. Raytracing is a technique used in the generation of computer generated imagery (CGI) to create reflective surfaces, so Rayverb allows you to change the position of your sound source within the room, change the material of the walls, apply material from a different ambience or even alter the proportions of the room, all in realtime.

Rayverb will be a VST plugin, but Prosoniq has just posted a standalone version for Mac OS 9 and OS X for download (3.3 Mb).

After the LynxTwo and L22 digital audio interfaces drivers posted in November, Lynx Technology has announced that a Mac OS X-compatible driver is now available for its AES16 audio interface. All 192 kHz interfaces by Lynx are compatible with the 3.3 v. PCI-X interface found on the Mac G5 models.

Synthetic Instruments (SI-KTK) is a CD-ROM library with 43 waveform sets and more then 250 individual synthesizer instruments. SI-KTK will work in Kontakt version 1.2 and up. SI-KTK's instruments are true subtractive synthesizer programs, taking advantage of Kontakt's synthesizer engine, filters and modulation capabilities. Carefully prepared and unfiltered audio spectrums has been programmed and sampled, using an Analogue Systems 5-VCO modular and a Waldorf Microwave XT. The instruments were made by combining the audio data with parameter and filter tweaking - inside Kontakt.