I'm about to buy another neck that I was going to have them cut for an LSR nut, and saw that Earvana has a drop-in replacement for the LSR shelf you have left if you remove an existing LSR nut. I'm a big fan of the LSR nut and would rather have that cut made at build time when the neck is at Warmoth in a jig where it can be done perfectly. That way, I could try an Earvana, and if I don't hear any difference, I can install an LSR without any trouble.
I don't know if I'm going to do the Earvana thing, though. It's $45 for a 20 cent piece of injection molded plastic, and I'm not sure everybody isn't being scammed on those things, much like audiophiles get scammed on cables, connectors, and whatnot.
If you go to
http://www.earvana.com/technology.htm (Earvana's site), they'll show you a graph of what kind of improvement you can expect from your tuning by using their solution.
However, the best improvement in a perfect world
using their data is only 4 cents, and that at only 2 spots on the neck. I did a little research, and found out that's the absolute limit of human hearing perception. In other words, less than that is imperceptible even if you've got the auditory perception of a 7 year old child, and even there it's in the lower mids around 2Khz. It deteriorates from there as the frequency goes down (or your age goes up), to where you need as much as a 40 cent change to hear it at the lower limits of perception.
So... what are we buying here? Sounds a little bit like snake oil, although I'm not saying that Earvana is lying, or not presenting actual fact. What I'm saying is we may be paying for something that's more emotionally satisfying than objectively discernible. Just because we can measure something, doesn't mean we can sense it. Our measuring tools are much more sensitive than our senses. I can measure the difference between the amount of force exerted by dropping a 10lb. weight from a height of 1 foot and a 10.1lb. weight dropped the same distance, but if you dropped it on my foot I couldn't tell you the difference between the two <grin>
I think Earvana is telling the truth about what they've learned, the product they provide, and how it performs, but I don't think it's perceptible. I suspect spending $45 has a placebo effect, where expectations provide the differences we think we hear. On the other hand, I
know an LSR nut reduces the incidence of string hang ups, which is a very real-world benefit to that product. If Earvana provided a nut built like an LSR with their compensation built into it, then you could install that knowing you were definitely getting something practical for your money. That it corrects for some things you can't even hear would just be icing on the cake.
But, I haven't tried the Earvana nut yet, so I'm sorta speaking out of school here. All I've got are facts, and you all know how malleable those are <grin>