With that in mind, I built a prototype using this mid, one Sierra-1 woofer and the NrT dome. The problem with this is that there is a significant difference in efficiency between the two different woofers and both the tweeter and the mid have to be padded down by at least 4-5 dB. This 3-way bookshelf speaker, or LCR, would only be slightly less expensive than our Sierra Tower and I was simply not able to get the performance I would have liked. The beauty in the Sierra Tower is that the sensitivity of the dual 5 1/4" woofers match the mid and that matches the NrT dome (and even the RAAL, which has a custom impedance / sensitivity profile for us). There is almost zero padding on any of the transducers in the Sierra Tower which means the efficiency on all the components is maximized.