The Sierra-2 most definitely sound different than the Sierra-1 NrT. In a blind listening comparison, I have no doubt at all that most people would be able to consistently tell them apart.

Now, will that difference cause you to prefer the Sierra-2 or consider them "better" than the Sierra-1 NrT? In my opinions, yes. The faster transient response and lower residual energy of the Sierra-2 give them a sense of greater realism, in my experience. It depends on the recording, but there are more instances where the Sierra-2 fool me into thinking that I am not even listening to speakers, but rather that it is a real live person or instrument making sound in front of me. With the Sierra-1 NrT, I would rarely be fooled, and I could pretty much always tell that the sound was coming from a speaker. So I personally consider the Sierra-2 superior in their sound reproduction.

If you already have Sierra-1 NrT speakers, and you cannot afford the RAAL upgraded Towers, then the Sierra-2 Upgrade Kit is certainly the way to go: http://www.ascendacoustics.com/Merch...t_Code=7SR2UPG

The Sierra-2 use the exact same cabinet as the Sierra-1 and Sierra-1 NrT. Dave F. went to great lengths and effort to make that the case. The instructions on how to do the upgrade are right here: http://forum.ascendacoustics.com/sho...ons-with-video!

It is not difficult at all. You are swapping out both drivers and the crossover. The cabinet, port, and binding posts remain unchanged.

As for getting the absolute best sound quality from your 2-channel only setup, all that you need in addition to the Sierra-2 Upgrade Kits is a pair of excellent subwoofers. Over on the AV Rant Podcast, Tom and I talk almost every episode about the importance of bass management, using 2 or 4 subwoofers, and positioning those subwoofers optimally within your room.

But since many people - especially 2-channel only listeners - still don't believe us, here is another podcast with the director of the Home Acoustics Alliance where they describe all the same things that Tom and I consistently repeat.

I loved one way that Gerry Lemay described the use of subwoofers in a 2-channel only setup, which is that you're just bi-amping your speakers! Many, many 2-channel only fans have zero problem with bi-amping their speakers, and yet they balk whenever subwoofers are suggested. So if it helps to get anyone over the mental hurdle, I love just thinking of adding a pair of subwoofers to a pair of bookshelf speakers as bi-amplifying a pair of full range speakers! That really is all you're doing.

However, by having those subwoofer drivers separate boxes, you also have the freedom to place them in the best spots, rather than being forced to only ever have them directly below the midrange and treble drivers. As we describe on AV Rant, and as Gerry Lemay describes there on that Home Theater Geeks episode, deep bass sound waves are so long that they exceed the dimensions of rooms typically found in homes. In a 9 x 13 room, they will definitely be exceeding your room's dimensions. As a result, you are NEVER hearing direct sound in the deep bass. You are only ever hearing reflected sound. So the notion of needing the bass drivers to be directly in line with the midrange and treble drivers goes right out the window. Instead, the bass drivers need to be located within the room so that the reflected sound you are hearing is smooth, even, and free from massive peaks and nulls that are created when the reflected sound waves bounce back the way they came and either double up or cancel out on top of themselves.

In the end, what you want to do is position at least 2 subwoofers so that they are directly opposite one another across the room - as in, the mid-points of opposing walls (either the front wall and back wall, or the two side walls), or just otherwise opposite one another across the room (one in the front left corner, the second in the rear right corner. Or one on the front wall 3 feet in from the left wall, one on the rear wall 3 feet in from the right wall). By having two subwoofers across the room from one another, you create the most even distribution of deep bass sound waves, and that prevents the formation of these gigantic peaks and nulls in certain seating locations within your room.

Since yours is a small room and you are only concerned with music listening, I would recommend the HSU Research STF-2 subwoofers: http://hsuresearch.com/products/stf-2.html

A pair of those mated to the Sierra-2 speakers will give you detail and extension that even the Towers RAAL (all by themselves) would not be able to reproduce. The issue is not how low or loud the Towers RAAL can play on their own, the issue is placement within the room. If the Towers are handling all frequencies on their own, you cannot position the bass drivers optimally within the room. They are stuck directly below the midrange and treble drivers, and they are both at the front of your room. There's no way around that.

But by bi-amplifying your speakers and having the bass drivers in separate cabinets, you are free to position those bass drivers where they will perform the best in your room, and you also free up your amplifier to only have to produce the midrange and treble frequencies, which will be handled superbly by the Sierra-2 bookshelf speakers.

Best of luck, and please come back and let us know how it all turns out for you!

- Rob H.