Mac OS X is the best Mac OS ever for audio, outstripping all other operating systems and platforms, new in-depth research shows.
The report – called Audio latency measurements of desktop operating systems – pinpoints CoreAudio as the key to OS X's strong audio showing. This is the part of the OS used by audio applications and peripheral devices to process and sequence sounds.
The research examined the audio latency of major operating systems running on modern equipment. It was authored by Karl MacMillan, Michael Droettboom and Ichiro Fujinaga of the Peabody Institute – part of John Hopkins University in the US.
Audio latency is defined in the report as the minimum time required for a computer to store a sample from an audio interface into application memory, and to copy that sample from application memory to the audio interface output. The authors also took the time spent converting analogue to digital and back to analogue sound into account.
Long latency speeds when working with audio mean that musicians experience delays in listening to what they play when trying to create music tracks. This also makes it challenging to record live performances - as the latency speed can affect the sounds heard through the monitors.
For gamers, latency speeds affect the realism of the playing experience - less latency means that sound effects play in real time, long latency means the sound of a gun can be heard after a player's been hit.
The researchers found OS X offered the best latency speed of all OSs and platforms when running multiple applications.
In tests, audio was sampled at 44.1KHz with 16-bit or 24-bit precision. Apple's machines were the only ones on test that didn't require a soundcard.
The best latency test results for systems without load were as follows (time in milliseconds);
- Mac OS X running on a 400MHz G4: 2.83 ms.
- Soundcraft Desk: 1.81 ms.
- 933MHz Pentium 3 running Linux 2.4.1 with a third party audio software patch: 2.72 ms.
- 933MHz Pentium 3 running Linux: 2.72ms.
Mac OS X performed outstandingly when under system load. It offered the same latency speed as before - 2.83 ms. Previous competitors in the unloaded category dropped out of sight. Its nearest rival (with 4.3ms) was again Linux 2.4.1 OS, this time running on a dual processor Pentium 3 with a pro audio card installed and additional software.
The report authors conclude: "The new CoreAudio API, which was introduced with OS X is clearly designed for low-latency performance, and allows multiple programs to access the soundcard concurrently. Only an experimental system called Linux Audio Application Glue API provided comparable performance."