It does sound, with the bit about the tone getting thin and tinny, like you're sending it a hotter signal than it can handle. Envelope filters in general are extremely picky about the input signal level. Some like it hot, some not so much. I strongly suggest anyone who gets disappointing results with any envelope filter try adjusting the level of the signal going in.
+1
The goal is to have the right amount of signal.
With my TRB5, the filter was very bad.
With my Stingray 5, the sound was ver nice.
And with my passive P-bass plus, the sound is not that nice.
I have to hit the strings harder to get the filter to open.
) Quite an awesome box, but it just wasn't getting enough attention from me.