Help with used "rock" speakers under 4K

I know its a bit of a deviation from your system but I'm currently using Magnepan 1.7's with a Velodyne DD-12 (second sub is on the way). I'm super satisfied with the setup and rock music is the bulk of my listening.

Adding a pair of subs would be your best route, IMO. You'd have to give up a lot of resolution to get a different speaker altogether with more thump. Maggies w/ sub is a minimal compromise solution.

ATCs make for the best "rock" speakers bar none..

That's a very large room. In my opinion, speakers that have a good dynamic capability and smooth power response with robust bass tend to be good candidates for a very large room (think "prosound-style but with smoothness and deep bass"). One way to get smooth power response is to use a big constant-directivity horn and a big woofer, and to cross over where the woofer's pattern has narrowed to match the horn's.

Have you considered something like the Altec Model 19? Long since out of production, the Model 19 is a high-output classic with very good bass and smooth power response.

Seldom available used, but within your price range new, the PiSpeakers 4Pi embraces essentially the same design principles as the Altecs mentioned above, but with more modern, higher-output drivers and an even better crossover. The designer, Wayne Parham, is a master. If you go for the 4Pi, get the JBL woofer and B&C tweeter upgrade, both of which are well within your budget.

Duke
dealer/manufacturer

thanks for answers
based on some suggestions please suggest me a good Sub that will go well with Mags 3.6.

Fafafion - ATC speaker , do you think it would be enough for the room ATC scm50aslt (i know its above my original budget, but if the extra 3.5K will make a good difference.... maybe)

Look into Cerwin Vega, I think that is a good fit for what you are doing. Very efficient and capable of pressurizing the room. No subwoofer needed.