(12-07-2014, 02:37 PM)Mr. Van Winkle Wrote:(11-06-2014, 08:55 PM)Ghost1958 Wrote: I use both filters but never had my machine whistle. Sounds the same either way. Never had to trim a filter out of the pack. But the foam one does or did on mine get stiff after some washing and started popping out. New filter is still pop out free so to speak LOL.
Maybe the old filter has swollen after being washed a few times?
Thats a thought but at least mine didnt swell or shrink. It just got stiffer compared to filter that is either new or had only been washed once or twice.
The new filter I put in which is still much softer than the one I had washed several times has never popped out since putting it in.
As to which side of the white filter to go out and which side in after eyeballing them closely a sunset filter vs a Respironics filter I noticed this.
One side is a bit more fuzzy and doesnt have longer flat fibers on it.. that is the side that goes out. The other side has courser fibers that are flatter and wider. That side goes in toward the machine.
Never had to trim a white filter but the ones I get shipped dont have tabs on them like the ones for the old M series did though same filter will work on both machines. They slip in with a bit of room to spare.
Never had my machine whistle with or without the white filer though.