Originally posted by HeiligenstadtTestament:
I'm really wanting to buy the PS-20 and I've only heard samples of it on the web. [/b]
I have no comment on the PS-20, I have never seen one, so I know nothing. Viewing its user manual, it appears to me to try to compete with the Yamaha P60 (low end of the better models), in features, price, polyphony, use of a control button enabling the regular keys to act as the function controls (instead of having conventional switch controls like others). For example, it says 64 polyphony, but the manual says only 32 on 5 of the 8 voices, including 3 of 4 piano voices.
FYI, you can download the user manuals for Casio or Yamaha at their web sites (Service menu) to allow you to fully understand how things work before you buy.
Normally the important issue for selecting a keyboard to learn to play classical music would be good quality weighted keys, as much like the feel of a real acoustic piano as possible. It says it has this, and probably it does... This is an expensive feature, and $300 keyboards are not likely to have this.
I was a rank beginner, didnt know what Middle C was at first, and after only three months, an inexpensive keyboard simply became unacceptable due to not having good weighted keys. I had to replace it for that reason. Its been a year now, and I'm doing fine, but am still not really to the point where the sound matters so much to me yet. I'm still concerned with just trying to get the keys played.
You are stressing quality of sound, and that's great, but sound quality comes from two issues, one the basic quality built into it, and also the amplifiers/speakers you use to listen to it.
All of these keyboards provide small internal speakers, typically little 4 or 6 inch speakers, comparing more to a larger table radio than to a stereo system.
It is easy to do better, sound-wise, and any portable keyboard can be much improved by using larger better external speakers, (which can in some cases cost as much or more than the keyboard). If sound is really important, this sounds like a necessary step. I'm using a Yamaha P90 with external speakers (mine are only in the $100 class), and I'm getting by just fine that way.
The only reason I bring this up is that it sounds as if you may be judging sound samples "on the web" you said. This then would imply that you may be using your computer sound board and speakers to listen, and it seems a real good bet that our computer speakers are probably not as good as even the little internal speakers in the keyboards. If this is the case, anything you listen to can only sound as good as your computer speakers, and so this may not be a meaningful listening test.
I do think you will want to judge the real keyboard (any brand) in a store. For better keyboards, the store likely will have the sound piped to larger external speakers there, so be aware of the situation. Downloading the manual first helps to know how to operate it there too.
There are some user comments of various keyboards at http://www.harmony-central.com/Synth/Data/#man
The PS-20 is not there, but other Casio like the current PX models are there, and most brands are there. Hope this helps.