Where to place Aurios?

Under feet of my Rega P5 or directly under chasis? Same question for cd player, amp, pre amp etc...under bookshelf speakers?
I place mine under the chasis. Placement is determined by balance and sound. Generally, I find that one placed under or near the power transformer and, if a cd player, under the drive motor improves sonics. Balance is usually influenced by cable dressing. Probably the biggest factor in placement is balance---finding the placement where the component will rock or sway freely for an extended period after being put into motion with a gentle push or tap. Also I use various combinations of Herbie's feet and Big Fat Dots on top or underneath the Aurios for greater isolation and improved sound. Don't be in a rush when you install the Aurios. It takes patience and more patience to find the sweet spot(s) and the right combination of isolation pads or, if you use them, bearings (I like what Herbie's feet do vs the bearings). However, I think the payoff is worth the effort.
I liked the performance of the older original Aurios MIB's.
But, because the original design of the MIB's (music interface bearings) did not self center and were slippery due to the spectacular smooth finish, these were almost impossible to keep 100% level to do their best. If you have the old original version, you know what I mean.
Subsequent releases utilize a self centering design which eliminates this setup difficulty.
I had used the slightly compressible and therefore reasonably self leveling Mapleshade Records "Isoblocks" on top and beneath the Aurios to enhance isolation, and the slightly compressible Herbie's products do somewhat the same service to aid Aurios isolation and leveling, but perhaps even better.
Herbie's variety of compressible footer products would definitely be more "high tech," but the old fashioned simple "Isoblocks" are quite versatile, too.
Also, there are generic versions of "Isoblocks" available from vendors on Audiogon as well as at plumbing supply sources.
No matter what footer is tried, there is not one "perfect" footer method which eliminates all future experimentation.
I finally had to abandon the older original version of Aurios because family members could not use component controls without displacing the older non-self centering MIB's. Additionally, whenever a visitor or family member would touch a component or speaker box the horizontal motion induced could fool someone into thinking mistakenly this was a prelude to tipping or falling which is definitely not the case.