Acoustic guitar feedback damper - tone loss?

Gearhead

Simple question: what are the ins and outs of soundhole feedback dampers, the do's and dont's and which ones are good and which bad?
Think http://www.deanmarkley.com/Accessories/Suppressor.shtml......

Keira-WitherKay

hey gearhead......... the feed back busters do work well........... especially if you have a bigger bodied acoustic....... the thing is the volume ..if the stage is louder a feedback buster will allow quite a bit more gain before you feedback....as for tone........ if you acoustic and playing that loud ... tone actually is not an issue and if you have an intenal pickup it shouldn't be much of a difference prob not even noticable to the human ear....... it's something i would only use if the situation called for it and remove it when you out of the feedback danger zone

aja

http://www.lutehole.com/

looky, more GAS material! Albeit much cheaper than the usual stuff that's posted here!