JBL LS40 a good speaker?

If you are going to drive them a little hard then the MA Silver 2 is not the speaker to look at. Monitor Audio makes some great speakers and I bought my daughter a set but they just don't play too loud compared to most others in their price range. Also if you want a little hot tweeter it's not the Monitor Audio's. I personally don't think they'd be great for studio monitors. A very nice speaker, easy to listen to, but not the most revealing. Not heard the JBL but unless JBL has gone another direction which I don't think has happened, they'll likely play loud and probably a little hot on the top but that can be controlled some and with techno or electronic music maybe more to your liking. If you can compare a set of Paradigm in your budget try them. They play loud and are often hard to beat in their price range. I personally prefer Monitor Audio over Paradigm but if you could compare them side by side the Monitor Audio's sound dull, but they're not; the Paradigm are easier to drive and model to model they will play deeper and can play louder without loosing it. The new Elac Uni-fi UB5 is something to look into as well.

thank you, this info about low volume output is important...

I'd consider Paradigm Studio 40s for instance but these can't be found easily here where I live... Anything else that Paradigm currently produces that would be worth a look?