Why do you have a component set running at 120 lpf? How do you know this? What processor do you have? I presumed he just typed LPF instead of HPF. For true midbass frequencies, having the speakers located in front of you doesn't really matter. But you would still want them as wide as possible.....under or directly behind the seats are both generally poor options.I don't see why you shouldn't be able to get performance under 120hz with them unless you are simply pushing them significantly past their output limitations. Are you playing them at an excessively loud level when they appear to start bottoming out? Completely disagree Impious. Midbass freqs should definitely be played by front stage drivers. Your comment on having midbass drivers as wide as possible is contradictory to your previous statement Midbass drivers are best mounted in the doors with proper deadening. Disagree if you wish, but you would be wrong. And the statements are not the least bit contradictory. If you think they are, then you are not reading them properly. We localize midbass in the lateral plane only (i.e. left to right). We don't localize it on a vertical plane (high and low), and we don't localize it "front to back". Midbass is localized by way of what's known as Interaural Time Difference (ITD). That is, the brain localizes midbass laterally due a difference in the time arrival of the sound wave between the left ear and right ear. ITD dominates our localization ques in the frequency bandwidth where the wavelengths of the soundwave are longer than the distance between our two ears. Our ears have no hearing mechanism by which to differentiate "front" from "rear" in the midbass frequencies. The wavelengths are too large compared to our hearing mechanisms to locate them vertically or "front to back". Generally the more ITD you can generate, the wider the potential imaging. From this very basic knowledge, a couple things can be extracted. First, any midbass location that results in identical ITD will be indistinguishable to the ear....above you, below you, in front of you, behind you, it doesn't matter......as long as the ITD stays the same, your ears and your brain won't know the difference. Second thing we should notice is that the WORST location for a midbass is at a location that results in an ITD of or close to zero; that would be DIRECTLY in front of you, DIRECTLY behind you, or directly above or below you. Since "imaging" in the lateral plane is a function of ITD, the "best" midbass location is a location that results in optimal ITD. Which is why I previously stated that you want the speakers located as wide as possible, to allow for proper ITD. So yes, you can mount midbass drivers behind you....your brain doesn't know the difference. Mount the drivers as wide as possible to maximize ITD. Which means, for example, if the ITD from some given location on the front doors and some given location on the rear doors are identical, you could mount the speakers in either location and you wouldn't be able to tell a difference. Now, a few caveats to this: First, hearing rattling/buzzing/etc as a result of the midbass speakers exciting panel resonances (door panels, etc) or other noises will ruin the illusion. Second, the speakers must only be operated within the bandwidth where ITD is the mode of localization. If you operate the driver outside of this bandwidth (this includes driver distortion, etc), then other factors will begin to contribute to our localization of the sound. Proper time alignment of the midbass drivers will need to be maintained with the other drivers in the system as well as between the midbass drivers themselves. Lastly (I think), this does not take into consideration the effects of other factors such as reflections, frequency response anomalies, etc as those will be a case-by-case basis. All that said....claiming midbass in the front doors is the "best" location is extremely generalized and I wouldn't necessarily agree.