Bass (mix) to mono?

Is there a (built-in) plugin to make (in the end) whole mix mono in the bass region?

Here are two free ones Besides these, you could use an EQ in M/S mode and highpass the S portion.

there's a built in one, LOSER/stereoEnhancer

Not free but a great plugin Mongoose

You can also do this with any eq plugin. Just get MS encoder/decoder plugin like Voxengo's free MSED and set up two instances of it on your fx chain, then set the first one to encoding and second one to decoding mode. After that you can put any eq you like BETWEEN them. Now in MS mode, left channel is mid data and right channel is side data so you have to disable left channel input and output from your eq plugin. This way your eq only works on side channel.

Or simply use an instance of VOS TDR SlickEQ which has a great third order HP filter (Melda free eq will do it, too, but I'm not really a fan of that plug).

I like LOSER/stereoEnhancer Also witti dynamics plugins pack has some nice MS plugins to monitor or change the mid and side signals. Don't underestimate the JS folder before searching for plugins out there. ;)

Another vote for LOSER/StereoEnhancer. Quick, easy and effective ;) - Mario

I think the more common approach is to center-pan the bass guitar and kick drum, and filter the low-bass out of everything else.