Go grab an old brick from the backyard (it must be a red brick!), clean it thoroughly, then paint it blue (you must paint it blue, and use at least three coats), and you’ve now got a great substitute for a Shakti Stone at a fraction of the price. The paint might set you back $10, but such a small price to pay for such an incredible improvement to the sound quality of your system. You can expect a lower noise floor, a wider and deeper soundstage, and more definition of the individual instruments. Go ahead and give it a try. You are likely to enjoy the exact result as described above.