We can all try to help him getting the bass he wants with the sub but if he wants more bass without the sub, then yes he can try to have some fun doing what you are suggested, as long as his SVS towers can handle the potentially over boost, at
certain volume setting.
When using without sub, he would have no choice but to set the speakers to "Large" so all our suggestions suddenly become moot.
For that scenario, I think his best bet is to contact SVS for suggestions, assuming Audyssey isn't the cause.