Note:
On a couple of old Bear grizzly, had some noise.
No matter the tune or arrow weight.
Turns out it was limb resonance.
Slapped on some PSE/Vibracheck limb bands and solved it.
Looked like crap.
Don't like Sims mushrooms either.
I run flemish strings, and the bows were noisy until the bands on limbs.
Also, being old B50 rigs, none were fast.
Nostalgia is cool.
But I got out of that.
Saved a bunch of old bows and decided my time, effort and loss of money was done LOL
My Howatt Hunter has some limb vibration I never remember it having when I shot it alot many years ago. I do believe it's resonance like you mentioned as it seems to continue after the shot.
