[Timo]

Even though I am yet to hear/play an Ion in action, the idea of Ion having all those different modelled filters - as well as new ones - sounds excellent. I wonder if Access are planning something similar, in addition to their Moog-emulated filter and their own filter.

Originally Posted by [url=http://www.soundonsound.com/sos/sep03/articles/alesision.htm

Sound-On-Sound - Alesis Ion review[/url]]
The Ion's manual is careful not to name the specific synths on which its various filters are modelled, but if I borrow some of its language, and you look closely at the two-letter names for the various types, you should find it pretty easy to guess.

* 'mg': a four-pole low-pass modelled on that of the most famous monophonic analogue synth ever made.
* 'ob': a two-pole low-pass closely resembling the one in a classic synth xpander... whoops, I mean expander module.
* 'ob': a two-pole band-pass.
* 'ob': a two-pole high-pass.
* 'rp': a four-pole low-pass modelled on the one in a popular semi-modular synth.
* 'tb': a three-pole low-pass (think 'little silver bass synth').
* 'jp': a four-pole low-pass (from an eight-voice synth noted for its coloured buttons amongst other things);
* 'Eight-pole low-pass': all the filters from here on were created for the Ion; this one gives a very steep cutoff.
* '8ve dual band-pass': two two-pole band-pass filters spaced one octave apart.
* 'six-pole band-pass': like an exaggerated version of the 'ob' band-pass.
* 'phase warp': an analogue phaser effect based on eight all-pass filters in series.
* 'comb filter 1': multiple resonant peaks and notches which are not harmonically related.
* 'comb filter 2': as above, but the signal is additionally filtered to warm up the sound.
* 'vocal formant 1': three band-pass filters emulating 'ah' and 'oo' vowel sounds.
* 'vocal formant 2': as above, but 'oh' and 'ee' vowel sounds.
* 'vocal formant 3': a five-band formant filter.
* 'band limit': a two-pole high-pass filter and a two-pole low-pass filter in series, limiting the signal to everything between them; resonance adjusts bandwidth.

That's quite an impressive collection ? imagine the hardware required to build a polyphonic analogue synth containing that lot! There are some beautiful filters here, ranging from the (A)RP low-pass that clips when it gets a loud input level, to the delightful phasing filter and the expressive vocal filters. They all respond smoothly, with only the maximum resonance settings (in some cases) proving a little harsh and digital-sounding. And with two such flexible filters to play with, you are not reduced to merely emulating such classics as Moogs, Oberheims, Jupiters and so on, but can go where no-one has gone before. Perhaps this truly is the first of the next generation of Virtual Analogues?