Discussion about the Korg PolySix synthesizer

Hi I just purchased a Polysix from Ebay of a German guy there seems to
be a minor problem which has been badly translated with I guess
babelfish "
Q: 	Hello again. I wrote to you earlier with a question. Now I just
wonder, could you specify that problem with the "low sound"? How loud
is it, does it disturb...more	19-May-07
A: 	One Voice must be configure new on the platine. thanks.

His answer is the part that confuses me could anyone shed anylight or
specifically explain what he might mean and is this a major problem!?
it would be much appreciated!! also

Q: 	Hi, do you know if the battery has been changed or if it is still
the original? Also, does that 'dumpf' sound get in the way of
playing?	20-May-07
A: 	Battery is original. The dumpf come every 5th time when playing
polymode or Arpeggiator. In Unisono Mode not.

Could anyone explain what is a "dumpf" sound I'm either missing
something obvious or it's another bad translation i was thinking a hum
that might have something to do with the other question.
I read that this can be a problem with some poly's and can be sorted
with some tinfoil, but I' m at a loss as to where i read that. Anyway
sorry for the long first post and would be extremely greatful of any help.
Thanks in advance

Sean