All speakers are sensitive to placement, but few are "true bookshelf" speakers.
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The issue you will have is that stand mounts are meant to be placed out in free space. Put them up against the wall and they'll get boomy.
If you wanted to DIY, you could make the LM-1 speakers which are designed as true bookshelves.
Conventional speakers (bookshelf & floor-standers) are voiced to be placed in a room, not against a wall or in a cabinet. They will always sound better away from walls, ceilings, or any type of enclosures.
However, in the environment you're putting them in, you might want to consider Center Channel Speakers. they will work much better than taking a regular bookshelf speaker and placing it on its side if hit has to fit the space, or give a better look, or go a certain way.
For your space, I would say look at the Paradigm Prestige 45C Center Channel - which incorporates a three way crossover utilizing a Tweeter, Midrange, and Woofer combination.
For a less expensive option, there is the Paradigm Premier 500C Center Channel Speaker that is also a three-way design.
Oh, another alternative is to buy professional, powered speakers. I say this because they often include bass adjustment exactly to deal with this issue. Like this one:
Check out the rear panel and see the "boundary trim"