I have recently begun using the Concrete Limiter.  Previously I used Boost and that behaved as I expected.  That is, when I set an absolute limit to -1dB, I didn't get any "red LEDs" on the meter for the main bus.
 
With the Concrete limiter, I keep getting the overdrive LEDs lighting up on my main bud, even when I have the limiter ceiling set to -4dB.  I am thinking I must be misunderstanding the sequence the effects are applied.  I have the Concrete limiter in the bottom slot on my main bus ProChannel.  I thought that was the last thing the out the door. 
 
I must be missing something basic.  I understand that because of sampling error, the output might be slightly higher than the ceiling, but not 4 dB.  Any idea what I might be doing wrong?

The right fader is the one you set for output. The left fader is the one you set for increasing the loudness. 
 
Leave the right fader at the top and you get no limiting. Move it down to the point you want your output not to exceed and it wont go over that point. 

Regarding the sequence of signal flow, the ProChannel is pre-FX bin by default. If you click POST on the channel strip, it moves to post FX bin. Have you got anything in there?

Excellent point John. That got me when X1 E came out.  

John T
Regarding the sequence of signal flow, the ProChannel is pre-FX bin by default. If you click POST on the channel strip, it moves to post FX bin. Have you got anything in there?

Ahhhh.  I think that's what is wrong.  I didn't know about that Post FX Bin setting.  Yes, I had a stereo widener in the FX bin.  Can you confirm that the processing in both the FX bin and in the ProChannel is top-to-bottom (in at the top, out at the bottom)?  It seems to work that way.
 
After making that change, I have the Concrete Limiter ceiling set at -2dB.  The limiter reads a peak of -2dB and my bus meter reads a peak of -1dB which I think can be accounted for because I am allowing the limiter to automatically set its attack time.  Some transients are probably getting through the limiter, but that's OK.  This setting seems to work as I expected.
 
Thanks.

Yes, it's top to bottom.

There's a signal flow diagram in the help file if you go having a look for it.

Yes, signal flow come in the top out through bottom in both FX bin and Pro Channel
http://www.cakewalk.com/D...amp;Req=Mixing.07.html

scook
Yes, signal flow come in the top out through bottom in both FX bin and Pro Channel
http://www.cakewalk.com/D...amp;Req=Mixing.07.html

That's very interesting and helpful, but unless I missed it, it doesn't really address the relationship of the prochannel and effects bis on the master bus.  But I think I understand how that is working now.

It does; look at the PC next to the effects bin, with the little switch symbols. That's showing you the two places in the overall flow it can go.
 
In terms of signal flow, there's no difference between tracks and buses, other than buses omit the clip section at the top.

I see your point; it gives a simplified version of the bus at the bottom, which is a bit confusing, IMO.