Had anybody tried this

Without a plan it’s like trying to solve ten simultaneous equations in twenty unknowns. The bells can hurt the sound in most locations. The trick is find the right locations. Three bells in the right locations produces better results than twenty bells placed arbitrarily. 

@geoffkait 

As you mention, there are too many variables, but it is not that easy to change placement behind the speakers with lot of cables.

It will take time and I will keep doing experiment few more days and report the progress.


@To everybody who like tweaks.

If you like lively sound with more sparkle, then you shall try this yourself.

It cost around 25 bucks for 10 bells and blue tack.

That is not much money for tweak.

There are lot of variables like positioning bell in the right direction.

My last comment is that there are a great many locations around the room, not just behind the speakers, where acoustic resonators are effective. The opposite wall, side walls and upper corners are the best locations. However, I kind of hate to say this, the *only reliable method* for determining locations for resonators like tiny bowls or bells is to use a test signal or two plus SPL meter to map out the entire 3D space of the room, finding points on the walls or wherever when the sound pressure is 6 dB or higher than the average sound pressure level in the room. All other methods will only get you part of the way or even make the sound worse than before. Especially when you put up a bunch at one time. Even the listen a little, move a little technique cannot compete with the SPL meter and will only find what we call a local maximum, at best.

After replacing Amperx 6sn7(Bugle Boy) with Bad Boy , the sibilance is almost gone.

I placed more bells behind the speaker close to the floor.
Wow bass got tighter and more tuneful.

I am listening to "The Wall" by Pink Floyd.

It sounds terrific.

You shall try this yourself at 25 bucks for 10 bells from E-bay, using Blutack