Hi Mondo,
Whilst it doesn't check *everything* on the Xpander, the init patch basically has enough to ensure everything is working. On a simple scale, the Xpander has only a couple of sound blocks in it -- a VCO to generate the sound waves (two per voice), a VCF which does the filtering (modes are selected by basically messing around with some inputs on this), a VCA to do the volume, and then the CPU does everything else (LFOs, Envelope Generation, Tracking, etc). The init patch on the Xpander is a sound which uses both oscillators, the filter set to low pass 2 pole mode which is put around halfway of its range, and then a basic envelope. It's not a particularly interesting sound, but it does use all the elements which the Xpander uses to make sound. So if there's any faults, you would hear it here by things like distortion in the sound; the filter being either too closed or too open; one of the waveforms being missing; etc.
To be honest, the Xpander's base sound of the oscillators and filter is ok, but nothing massively special. What adds the magic sauce is the complexity you can make of the patches and how good the sounds are when played on multiple voices. That is what sounds different to other synths.
To test anything else on the Xpander would really just check the CPU/ROM isn't slightly dead in a way that makes everything work except one specific thing. This is incredibly unlikely (such faults would cause the CPU to quickly crash on startup).
Cheers,
deano
On Tue, Aug 1, 2017 at 1:29 PM, ipc.de@web.de [xpantastic] <xpantastic@yahoogroups.com> wrote:
Hello friends out there,
It puzzles me, but how can even a considerable indentity in the "init patch" (which is a most simple patch) tell that a synth is technically fully functioning? Like if you would judge the performance of a car just by listening to the machine idling.
I would say, the init patch of all things sounds most similar in all synths. I am sorry, the posted sound files sound much like a patch on my Roland alpha Juno. What does this tell us? Blow the fuse in your Oberheim and you have a Roland?
Cheers,
Mondo