See below for more clarifications. Hope these help.

-David.

> 1. ar wgpluck2 iplk,xam,icps,kpick,krefl
>
> A krefl value of 1 means no reflection at all and 0 is total
> reflection
> (therefore this is an absorption coefficient). The manual
> says the opposite.
> (there was recently a short thread on this problem)

Yes this does work opposite. The documentation will change to reflect this situation.

> -----------
> 3. ar wgbrass kamp,kfreq,iatt,kvibf,kvamp,ifn [,iminfreq]
>
> This line (similar to the manual example)
>
>
> error:  insufficient required arguments, line 3:
> a1  wgbrass 20000, 440, 0.1, 6.1, 0.05, 1
> 1 syntax errors in orchestra.  compilation invalid
>
>
> Does that mean that there is an undocumented argument before
> ifn, for example
> an idetk-time similar to the other wg opcodes?

Yes. Syntax should read:

  ar wgbrass kamp,kfreq,ktens,iatt,kvibf,kvamp,ifn [,iminfreq]

ktens represents lip tension.

> 5. ar shaker kamp,kfreq,kbeans,kdamp,knum,ktimes [,idecay]

> BTW, what does a frequency of a shaker really mean??
>

Frequency is the resonant frequency of the shaker's gourd.
And in case someone missed my previous post, syntax should be:

  ar shaker kamp,kfreq,kbeans,kdamp,ktimes [,idecay]