Is there a way to do a tone knob like effect with an acoustic without audio effects?

Question

I'm talking about adding or taking away treble progressively as a note rings.

You can ring a string unmuted and then slowly add muting as it rings, to give the impression of the treble decaying. Is there a way to do the opposite, start with a string muted (or use a bass string version of the note) and then make it start being trebly without re-sounding the note, and without taking away too much sustain too quickly?

Here is a simulation of the ramp up I made on a computer, followed by the ramp down effect which I just played by progressively muting: http://vocaroo.com/i/s0dcsg4IwFN0

Doesn't have to be exact, but any technique like this?

Things I've tried:

Playing the string muted, but then clattering a finger nail on it a little, to add some brightness. It's really hard (basically impossible so far) to get enough control of this, and also not stop the note ringing.

Playing the string muted, but then trying to progressively add fret buzz for the brightness. This is also really difficult to have any control over, and to not cause the note to stop sounding.

edit:

After more experimentation, you can half do it with a slide, or maybe if you had a ring on your finger. If you very briefly tap a ringing string with the metal, you'll introduce some brightness that stays with the string as it decays. It's not progressive though. You've got a muted string sound, and then you tap it, and the brightness is instant. Another drawback is that this will change the pitch. Probably doing it in key and very fast is better.

Answer 1

To increase the treble after sounding the note, there's no easy way of doing that.

Interfering with the string after sounding it is about the only way I can think of doing this, and as you've found it's hard to control.

Other possibilities would include using a bow, or an e-bow device, but these would produce something unlike the normal guitar sound. (And the e-bow would be an electronic effect.)

One idea I just had is to try covering the soundhole with a spare hand (or holding the instrument behind an obstruction like a pillow) and see if uncovering it as the note decays can add treble. This might produce an audible difference for the audience depending on where they are seated...

Answer 2

Well, getting the harmonics back into the string is not all that feasible. You can instead try to get the fundamental out (touch the string very lightly at a flageolet position).

Another possibility is getting the harmonics temporarily away from the body of the instrument as that is the main transmitter and then admit them. And you don't want to dampen them in the mean time as much as reflect them, or there will be nothing to admit. So maybe pressing something made of hard rubber rather close to the saddle? You'd need to experiment to figure out just what may make a dent in the harmonics rather then the fundamental as well. Basically the idea is like with a violin mute, just in reverse.

But I'd not put too much hope into that approach.

Answer 3

Two things I have done which effect tone brightness with some kind of sustain:

Rotate the guitar around the axis of the neck so that the sound hole turns away/toward the listener. I've done this for a sort of tremolo effect, but if done slowly, it might imitate a tone swell. You must get a lot of volume at the start to make it work.

Finger a chord on the neck then pat the strings with the flat of your fingers or palm so that the impact sets the string vibrating. This is not exactly what you asked for, because it re-sounds the strings. But, you can control the brightness of tone by changing the force of the patting and closeness to the bridge. It can create