What are you trying to tweak improve?

As I have an all digital system, two aspects of music that I am very sensitive to are glare and smearing in the upper mids and low treble. But other parts of music that are very important to me are timbral richness, especially in vocals, and also PRT. It's been my experience that PRT can be significantly changed by choices in vibration control.

Minimizing smear and glare and maximizing timbral richness seems mostly related to component (including speakers) and wire choices, and room acoustics. So, it's these properties of music that I've spent a lot of time, money, and effort trying to "tweak". Some tweaks work, some don't, and some make things worse-- maybe that's what keeps it interesting. Cheers. Craig

As I see it, the tweaking is like using a equalizer. Any tweaking method will affect certain frequency(increase or decrease it). My experience is that using hardwood like Ebony or Purple Heart are very effective in altering the sound. When using it properly, it adds harmonic to vocal or any kind of acoustic instruments. Making it sounds very natural, full of life and very realistic in the presentation. Other material like the Black Diamond Racing cone, the BDR shelf, carbon fiber board, grainite or marble slab all have their own character.
In general, hardwoods give the system more warm, musical and softer presentation.
Other materials like BDR cone/shelf, carbon fiber board, grainite/marble will give the system a more bright, analytical, sharper(less natural image), dryer presentation.
Usually a well-tuned system will need to a mixture of the above materials in order to make it sounds nice and balance.
It is like cooking, everyone have their own mixture of spices......

Every time I tweak or upgrade, I find myself listening for improved realism -- the illusion of musical presence. Specifically, I'm looking for clearer highs and stronger dynamics.