Most major audio-application developers are set to begin releasing Mac OS X versions of their software later this year.

BitHeadz, BIAS, Emagic, Sibelius, Noteheads and TC Works are aiming to release Mac OS X versions of their applications in autumn and winter.

BitHeadz plans to release Unity, Retro and Phrazer first, with ports of its other applications following later. The company is engaged in early beta testing of its products. BIAS announced Mac OS X versions of its applications, Peak and Deck last week.

Steinberg and DigiDesign however, have been reticent in discussing their OS X plans. A statement on Steinberg's site reads: "Presently, there are no drivers for audio and MIDI hardware from the hardware manufacturers themselves, so releasing an unusable OS X application is not very useful to our users.

"We have decided to target resources to advance the development of Steinberg's MacOS 9 applications. Cubase will run on MacOS X when the next major revision becomes available. Native OS X drivers will soon be available for our hardware devices as well."

An Emagic source confirmed: "All current hardware related drivers that use ASIO (Audio Stream Input/Output, developed by Steinberg) are not presently compatible with OS X due to fundamental differences within the new OS."

Lack of ASIO support in the current OS could be behind Steinberg's reticence in announcing its OS X migration plans. An insider told Macworld: "It looks like Apple have to cooperate with Steinberg before they can release an OS X version of Cubase VST. Apparently Apple haven't given them all the necessary OS code to do this."

The source did confirm that Steinberg and Apple have been working together for almost a year to develop the port. It is thought that Apple plans to integrate support for Steinberg and ASIO into CoreAudio.

OS X implements a new system for audio, called CoreAudio. The company's stated mission with this is to deliver: "A superior listening experience for Mac users, and to provide developers with an OS-level "Core Audio" system that frees them from relying on third-party audio and MIDI protocols in their applications."

It integrates certain features traditionally created by third parties multi-channel mix engines including DSP (digital signal processing) and virtual instrument plug-ins.

A BitHeadz source discussed the hurdles to Carbonization: "Apple MIDI and sound just happened a couple of months ago." He also discussed developer's concerns about Carbonizing apps: "The jump to OS X is rather large. Carbon is cool, but it's not clear whether it's a long-term solution, or a short-term bridge."

"The development path is a mess, Apple wants Cocoa, but Metrowerks wants Carbon," revealed the source. Many developers have complained that Metrowerk's development tools have been lagging behind the variously released Mac OS X updates, posing challenges to hassle-free development.

Christina Berkley of Bias, makers of Peak and Deck told Macworld last week: "The current shipping version (OS X) is lacking some critical features of the Core Audio engine. However we will soon be seeded with the beta version of OS 10.1, which is said to have complete audio functionality."

Ralf Schluenzen, CEO TC|Works, manufacturers of Spark, said: "Our developers like the potential they see."

CoreAudio features built-in MIDI management. Apple has added a new MIDI services API to OS X. This has a new MIDI driver plug in model and new OMS-like programming interfaces for applications to talk to MIDI hardware. Doug Wyatt, developer of the industry-accepted OMS (Open Music System) is working with Apple now.

However, both Steinberg and DigiDesign recommend users install Mac OS 9.0.4 on their Macs in order to use these applications to make music. This is because OS 9.1, which is the Classic OS of Mac OS X is unstable with the companies solutions.

"A lot of work has been done to enhance and add functionality and support to Mac OS X 10.1 for audio developers - especially with regard to MIDI support," confirmed an Apple insider.

There is some hope for early adopters. A third party unofficial solution called MusicKit is being ported to Mac OS X. It's a collection of drivers for synthesizing and performing music, as well as recording and playing back audio files. Written in Cocoa, the kit is mainly a cross-platform development kit for computer music programmers. Though the port isn't complete, MIDI and score file playback work well.