Greetings! I'm JP. First post. I am putting together a music-only system. I carefully listened to these two comparison videos in the same room with the same equipment:

NrT Tower:
https://www.youtube.com/watch?v=TFxC-1jsXw0&t

Sierra-2:
https://www.youtube.com/watch?v=Q-7AcN0mscY

Overall, I much preferred the sound of the NrT Tower because it brought the guitars more forward, making them easier to hear. I thought the vocals sounded very good on both speakers, although a little different. I can hear the added smoothness and slightly more natural sound on the Sierra 2 and do hear the advantage of the RAAL there.

During my research I have read the following quote from Dave:
The characteristic you are describing between the Sierra-1 NrT and Sierra-2 with regard to male voices being more upfront has nothing to do with the choice of tweeter (at least not directly as you are presuming). The Sierra-1 NrT is a more "forward" sounding speaker than any other we offer. This was part of the plan for this speaker -- to make it more aggressive, more forward in its presentation, with more high frequency detail and energy than our standard Sierra-1.

This characteristic you describe is fully controlled by the crossover, it is a function of where the tweeter and woofer cross and the overall balance of energy throughout the speaker's bandwidth. We could design the Sierra-2 and make it just as forward or even more so than the Sierra-1 NrT. That particular type of sound, while appealing to you and others, is generally not as appealing to the majority -- who mostly prefer a more neutral balance in the soundpower response (all of the energy the speaker produces, both on- and off-axis)

That said, with regard to forwardness -- the Ribbon Towers and the Dome Towers are about the exact same. Both options are a bit more forward sounding than the Sierra-2, but less than the Sierra-1 NrT. I would describe the towers as being directly in the middle of the Sierra-2 and Sierra-1 NrT when it comes to forward presentation.

The question you need to ask yourself in deciding between the ribbon and dome for the towers is timbre accuracy, detail, and smoothness. For accurate timbre and detail in the upper mids and highs, the RAAL is unmatched. I *strongly* recommend it for audio bliss (as this is what you are trying to achieve) Our ratio of ribbons to domes is about 80% to 20% and this has nothing to do with home theater, but because of music. I would also say that 25% of our dome customers end up having us upgrade to the ribbons whereas we have only had one customer have us convert from ribbon towers to dome towers.

Now – if you prefer a more rock and roll, more aggressive top end response – something a bit brighter, a bit more HF energy into the room – (what most listeners are more used to listening too – unless they already own speakers with RAAL ribbons) – the dome towers are a good choice.
It seems both Tower versions will be a bit more forward than the Sierra 2, which is what I want in terms of bringing the guitars forward, based on the comparison videos. Is that correct that the RAAL Tower will bring the guitars foward in the exact same manner the NrT Tower did?

Can you clarify what you mean when you say the NrT Tower & RAAL Tower are equal in terms forwardness yet the NrT is a bit brighter and more aggressive? In my mind, those things contradict.

I listen to a lot of heavy metal, with good quality recordings. I occationaly listen at high SPL, over 100db, but mostly around 90db. I have been told by the creator of those videos that the NrT version will be better for me, as the NrT will give a bit of a "meatier" sound for my music. The creator of the videos has not heard the RAAL Tower to my knowledge, so I'm wondering if he misjuding the RAAL Tower sound based on Dave's crossover & voicing information quoted above.

I want to preserve the guitar fowardness I heard in the NrT Towers first & formost, and at this point leaning toward purchasing the NrT Towers. I am hestiant to purchase RAAL Towers but if they will do the same thing with guitars, and add a bit more smoothness and natural realism in the vocal department, then perhaps I should?

Room is 14x12x10. Carpet floors.
Dual Seaton JS-12 subwoofers.
Onkyo NR901 being fed .wav files digitally.