Hi yolo...I have the qacoustics q7000i setup at home. I have tried it in various configurations as under mentioned:
1. In 5.1 setup with a Sony str-dn 850. Sounds good for music , but I did feel the lack of scale in 2 channel mode with the two speakers spaced 5.5 feet from each other. And with self sitting at 11 feet from both. But if when I move the speakers to 4 feet from each other and sit at a distance of 5 feet. The scale sounds too good for such diminutive speakers. But as I have a 65 inch TV, and have to sit at 11 feet from the TV, I have replaced the front speakers with the concept 40's.
2. In the above configuration, when listening in 2 channel mode without the sub, I did feel the lack of bottom end in bass heavy tracks. However, it was only in very few songs on a average. Otherwise the bass from speakers so small is really surprising. Just don't expect it to go anywhere below 90hz.
3. Now i tried using the 7000 LRi speakers for musical duties in my dining room, with a bluesound powernode. And the QA sub. The powernode has sub out, with cross over set at 80 Hz. This combination really sounds amazing. So much so, that iam disappointed with the concept 40 speakers so far. I know that they are mighty better speakers. But will need considerably better and expensive amplification to beat the powernode and QA 7000 LRi combination.
From above, below are my observations:
1. The NAD D3020 is very identical to the powernode in power output and class D amplification. So if it has a sub woofer out, then please buy the sub to hear this small but huge sounding system in all its glory.
2. This is also important. The ideal cross over between the sub and the speakers in my room is actually 120hz. Since I cannot set that cross over on my powernode , iam keeping it at the fixed 80hz option. And some times, just sometimes I feel that void in the bass, which I suspect is between the 80 to 100 Hz region. Again I didn't measure it, it is just my opinion, and I could be wrong by a mile.
3. So if the D3020 has sub woofer out , and bass management. Then setting the cross over at 120hz sounds ideal. But this makes the sub sound more localised due to the high cross over. So when I placed the sub between the left and right speakers , everything blends beautifully, and I just can't make out where the speakers stop, and the sub starts .
So all in all, if you have place to place these two satellite speakers 4 feet from each other. And place the sub in between, then they will really do justice to your investment. And the scale will blow you away. But again, even iam new to hi-fi. So please audition before you buy. And please bear in mind the subwoofer positioning as mentioned above. The positioning of the sub is the make or break of this system in my humble opinion. All the best....