Re: [LAU] About Algorithms

Moshe Werner wrote: Fairlight ESP, manufacturers of the MFX2, MFX3 and MFX4 DAWs. Back in the late 1990s one the of big differences between the Fairlight and Protools was that the Fairlight did is mixing on Analog Devices Sharc 21k floating point DSP chips while Protools was (I believe) built around the Motorola 24 bit fixed point 56k DSP chip. The rounding and truncation behaviour of the floating point chips sounded better than that of the fixed point chips (or so I was told and actually makes some sense from an engineering point of view). All modern DAWs which do the audio processing on the host Intel/ AMD CPU should be using floating point or SSE instructions and hence should have the good properties of floating point. I really think there is only really one mixing algorithm, its basically just multiply all the sources by their respective gain values and sum it all together. Other things that my be at play are things like different compressor, limiter and filter algoriths all of which definitely do have multiple ways of being implemnted. However, the biggest differences are probably in the analog-to-digital input or the digital-to-analog output. For instance, one thing that made the Fairlight MFX really popular on the foley stages (recording big bangs and crashes for sound effects) was the fact that the Fairlight had a basically flat low end frequency response. The test equipment we had at the time showed it was basically 1dB down at 10Hz which was the lowest the equipment measure. We suspected that the -3dB point was actually around 5Hz. Finally since A-D and D-A sections are highly susceptible to picking up electrical/eloctronic noise from the rest of the system, a part of the character of different machines is actually due to the noise it picks up from the rest of the system its installed in. This is a very big field and can go from cloning the input/ouput charavtyeristcs of a device to the extreme of programming digital models of analog elctronics components and then hooking them together. HTH, Erik -- ---------------------------------------------------------------------- Erik de Castro Lopo http://www.mega-nerd.com/