While I haven't managed to test the nx-45a or the new RCF art 9 series, I have tested the older Art 7, specifically the art 745 mk 2s and hd 45s as well as the srx815p's. I ended up buying pair of the srx815p that I've had for about 2 years now. From my experience when I demo'd the art 7 and the hd45s, they both got really loud. They produced clean, clear sound, better than the JBLs. However, the srx815ps I demo'd got a bit louder and had a more pronounced mid-range and more thump in the low-end. The art boxes are known for clear highs which is true, but they were lacking in the mids. The lows were there, but just not as thumpy as the JBL. I went with the SRX for this reason. The hd 45s sounded almost the same as the 745s, but when pushed, they were starting to produce a little bit of a rattling noise and starting to distort a little bit. I mainly DJ for wedding receptions, birthday parties and once in a while I do baby showers. Most of the time I DJ indoor and the srx can handle 150-200 people without a sub. If I need the extra bass because of a larger venue, I bring out my prx618s which do the job. I rarely push them past +9db on the volume knob and you could set eq profiles via networking to the speaker. The srx are heavier than the rcf, but I have no problem getting them up on the stands by myself and I'm 42 about 5'9 and 155lbs. However, I strongly advise you to demo them yourself as these boxes are not cheap and you might have a different preference in what sounds good. Everyone will have their own opinion about the sound quality of each box. Overall, I would recommend the srxs if you want clear, loud sound with deep bass that you can run without subs.