Is a Sub required for HT

Yes, you want to hear s**t blow up. 

Also, if you want a super quality sub at a great price, look at my listing for a REL T9. The REL allows you to run a cable for the LFE sub on your Marantz and also to run the Speakon cable from your speaker terminals. The result is great HT effects and better integration when playing music. 

I have a SVS Sound Cylinder in my HT setup. I like it in that system for music and music channels. There are a lot of good options out there.

Regards

I purchased an SVS PB 2000 today...no complaints!

Great choice.

Love my SB13 Plus

Bill