FabFilter User Forum

Pro-L 2 - Can it limit with a ceiling lower than 0db?

YES, I know there is an output knob. But after experimenting I found that this is not a TRUE limit ceiling. The limiter still limits at 0db, then the output knob just lowers the total output level. It doesn't actually limit at (for example) a -0.50db output ceiling.

Is there some undocumented way to set a lower ceiling?

If not, this really should be added. It feels like Pro-L 2 has pretty much everything except a true output ceiling option. (Maybe the developers felt that would make it too much like a compressor?)

For now I have to use Sinus's old Peak Compressor 2 from 2007 to limit with a true output ceiling lower than 0 db. Ridiculous! ;)


Hi Tinkerer,

Pro-L 2 (and v1), work a bit different than most brickwall limiters. Instead of lowering the threshold, you simply add gain to apply limiting. If your ceiling is set at 0dB, this will be your ceiling. However, if you lower the ceiling with the output knob you effectively have a ceiling lower than 0dB. Its yields the same result! Just make sure you enable True peak limiting when you do this! ;-)

If you have any more questions, just let us know!


This is exactly my question. With TPL on and the output set to -0.03, I'm still getting 0.0 on my master.

I didn't really understand the reply here. Is there a way to get a lower output than 0? If not, why is there an output knob?


Sorry, meant -0.3 not -0.03.


Hi Buhje,

Your output level will set the ceiling. Reducing the output to -0.3 will result in a ceiling of -0.3 dBtp. If this doesn't happen in your situation, could you send us a short video that illustrates this issue? You can send your video to info@fabfilter.com

There are a few ways to interpret true peaks, but generally most analyzers will use the same standard. In earlier versions of Pro-L 2, we used a different standard. This version was actually a bit more accurate in measuring true peaks, but less standardised in the industry thus causing some questions among our customers. What version of Pro-L 2 are you using? Also what analyzer are you using on your master bus?

Thank you in advance!


Hi Maarten,

I'm using the latest release of l2. Just downloaded it the other day. I've since tried it on a 2nd track and am getting the proper ceiling on that one. I thought I was doing something wrong, but maybe there's just something weird with the 1st track. I will keep playing with it.


So - just to get this right (because it is what I found out and it is not said in the manual, but should be): When I did a master with an output ceiling of -0.1dBTP, with TP limiting, and afterwards, to make it compliant with Spotify, did a second export of the file with the ceiling lowered to -2dBTP, there was NOT going on an increased amount of gain reduction / limiting, but the second file had the exact same amount of GR / limiting and only the output was reduced to -2dBTP AFTER limiting.

If so, thank you, FabFilter! You guys are geniuses.

But please include what the output setting does and that it does not affect the actual amount of GR / limiting at all in the manual.

Looking forward to your reply!

Kind regards,

P Welsing

Hi Philipp,

You're describing the effect of the output level correctly here. :)


Frederik (FabFilter)

Why, thank you!

This is exactly what I need as a professional mastering engineer, preparing final masters for Spotify, Mastered for iTunes and the like.

Thanks again for your thought through products.

Even though I always get confused trying your de-esser. It seems I just don't get that thing.

Everything else is just 100% quality.

Best regards

P Welsing

Oh, and please include the detailed functionality of the output section in the manual.
It makes things a lot clearer, I think.


P Welsing

I've been using the L2 recently and when I set the output threshold to -0.2 db, it doesn't limit it at this volume. Is there a setting that I'm not turning on properly? The L2 has been a gain knob for me and that's all.

I have TPL turned on as well.


Hi Dylan,

Do you mean that when you set the output to -0.2 dB in the bottom bar, you still see levels exceeding -0.2 dB? If so, do you see this in Pro-L 2's level meter, or in the host?


Frederik (FabFilter)

How do I set the ceiling to smash the sounds to not have levels go above that? I have a track in a session where it has 2 snare sounds on the same track. One sound is too loud compared to the other, and I want to smash them down (limit) them so that their levels are the same.

Adam Slawson

Hi Adam,

You would have to push the track into the limiter using the Gain slider, so that it will limit the signal the way you want to. Then you can back it up by using the output button in the bottom right.


Ralph (FabFilter)
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