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Why do you say they won't go below 150Hz?
Probably something about wavelengths and apertures.
The wavelength at 150Hz is already over 2m, more or less an order of magnitude larger than the effective baffle diameter. The speaker becomes an omnidirectional radiator, whereas at 1.5kHz it is quite directional. Because the energy at low frequencies is spread out over the full 4π sr, the sound pressure level at the listening position will be corresponding lower for a given total radiated power than it is at high frequencies where it is concentrated in a much smaller angle. If you correct for this by filtering (boosting the input power at low frequencies), you just end up with a very powerful omnidirectional radiator, which is going to sound pretty nasty in anything other than an anechoic chamber. Also, the amount by which you would have to boost the LF input would mean your woofer's voice coil would also serve as your room heater.
TL;DR: Small speakers can't have a flat response at low frequencies, because physics.
If they can perform under 150hz they are defying science. There's bound to be a bit of fitting the room involved though. I would watch out for room modes and the one note bass effect.