I've just tested and compared these three systems, playing the Roland SonicCell and BK-7m factory demos really loud at at least 60% maximum volume.
- HK Lucas Nano 300 with 2 tops (center of the picture)
- 2x db K300 (grey speakers left and right)
- 2x FBT J5a (one black, one white speaker).
Guess what my conclusion is...

I will describe the differences later in detail, but in a nutshell: except for the strong deep bass, where the Nano logically ranked first by far, BOTH the pair of db K300 and equally the small FBT overpowered the Nano 300 regarding mids and highs, and a piano sample sounds noticeably richer and clearer through both of them.

So, to give a brief summary of my testing:
First, overview of the weight and watts RMS of the systems:
- HK Lucas Nano 300: 10.3 kg (22.7 pounds) / 230 W RMS
- pair of db K300: 10 kg (22 pounds) / 2 x 120 W RMS
- pair of FBT J5a: 7 kg (15.4 pounds) / 2 x 120(/90?) W RMS

The big winner of this comparison was the FBT J5a. At the quite high volume I tested (speakers 60%, BK-7m 60%) it had the same high sound pressure as the other systems, although the speakers are so much smaller. As I said, the deep bass from a subwoofer is missing, but there are upper bass frequencies of down to about 80 Hz, and the speakers sound warm and clear at the same time. No distortion at this volume. Very rich and full sound overall and especially for piano sounds. (Note: In most specifications they are rated 2 x 120 W RMS, but in one of FBT's specs I additionally found "2 x 90 W RMS continuous").

The db K300 seemed to deliver the same volume and sound pressure as the incredible FBT. Their bass also goes to probably around 80 Hz, the overall sound is a little less warm and more crisp than the FBT. They are even more detailed in the high frequencies compared to the FBT. At some points (drum breaks, high brass) the crisp highs hurt a bit in the ear, but it could be an advantage in situations where loud chatter of the audience absorb the high frequencies. I suspect the K300 can be turned even louder without distorting compared to the FBT, but this volume was all I could bear in our basement, and at that volume none of the speakers distorted.

The Nano 300 impresses with its deep bass, so it delivered the 'mightiest' sound at firt glance. But focusing on sounds like piano during the BK-7m factory demo, it is evident that some middle frequencies are less clear compared to both FBT and db. So it depends what you want. If you want the floor to vibrate, the Nano 300 would be most suitable of these three. If you play a lot of pure piano or symphonic sounds with strings etc., both the FBT J5a and the db K300 will deliver a clearer sound at the same volume.

I am torn between FBT and db. Taking the weight into account, the FBT are the more efficient ones. On the other hand, the very clear highs of the db may be an advantage, and the db may have an even higher maximum volume without distortion.

Thanks for taking the time! I have a pair of FBT Maxx 2A's that I got about 7 years ago, and they deliver great sound. They weigh about 28lbs each. They deliver bass down to 50hz.

As you know, I do the senior circuit in the Chicago area. I almost never get volume complaints even though I play at a decent volume. I think that attests to the high quality sound, that there isn't any listener fatigue.

I'm very curious about the Bose and some of the other systems out there, but I already own this one. It's never given me a problem in the last 3000 + gigs that I've done with them.

I wouldn't want to try some of these smaller systems because I wouldn't want to lose the bass.

Good luck choosing!

Yes, FBT is a high-quality manufacturer. For some reason, they are not so well-known, similar to db (which are in fact a sub-brand of RCF, as I recently learned). I am currently considering to replace the Nano 300 by the subwoofer of the brand-new Bose Companion 50 PC speaker system and combine that with the db K300. This subwoofer only weighs 4.6 kg, and for my specific purposes it will probably be perfectly adequate.

I've decided to keep the Nano 300, as my band will have a gig again after a long break, and for such occasions (small audience) the Nano in combination with the db K300 is perfect. Powerful enough to play along with a drummer. For that purpose, a Bose computer speaker subwoofer wouldn't do the job of course.

But yesterday I was able to test the brand-new Bose Companion 50, the subwoofer is indeed only 4.6 kg (10 pounds), and the system sounds fantastic. Would be a great little sub to add to the db K300, but I won't buy it without selling another one of my too many speakers...

If you wanna hear something amazing try One Or TWO NANO Hk Lukas 600 systems on stage OMG!!
I love mine..so easy to transport & setup too. They got it right this time for the pro gigging player..