best wood for speaker cabinets ? oak,cherry, balti

Matt - I don't quite understand analogy with guitar woods. Cedar and Spruce are two woods with the highest strength to weight ratio and often used for the guitar tops to make it vibrate well. You don't want vibration and the one of the best materials is high density MDF or stone (marble, granite etc). Some speakers (like Paradigm) have internal crate in form of crossing boards along and across that have holes (circles) cut outs resembling honeycomb. Some more expensive speakers have either irregular shapes or round sides getting narrower at the back, to prevent standing waves.

MDF and cover with hardwood would be my choice!

As I recall, Audio Note speakers evolved from MDF to Baltic Birch for a reason. The drivers and the minimally-braced Baltic Birch cabinet are designed to work as a unit. The interaction has been likened to the way a stringed instrument projects its sound. While it might be fun to experiment with different cabinet materials, it is not how (and why) the speaker was designed to produce its characteristic sound.

As an aside, I believe that some of the older, original Sonus Faber speakers designs are made from solid wood. They used multiple small pieces, rather than large boards and just the sides are wood. The staves, as they call them, are carefully dried before assembly. It is a complicated process, more akin to furniture making than typically speaker making. I do not believe they have continued that tradition with some of the newer models - my guess is that they have moved away from that process for economic reasons.

I'm with GSM as well.

Always fun to experiment though I suppose. That's worth something....

I'd keep an eye on re-sale value though were I to tinker with an already well received and not inexpensive design, like the Audio Notes.

But I suppose, as long as you have the ability to take it apart and start over again as needed, or that you are open to living with the results whatever that may be, there is no harm with tinkering in the long term.