FabFilter User Forum

Pro-Q vs Proq-Q2

Pro-Q High Cut 200 Hz 48dB/oct Linear Phase - Low:

Pro-Q2 High Cut 200 Hz 48dB/oct Linear Phase - Low:

Pro-Q Low Cut 700 Hz 48dB/oct Linear Phase - Low:

Pro-Q2 Low Cut 700 Hz 48dB/oct Linear Phase - Low:

Why is there so many residual information in Pro-Q2 and not in Pro-Q beyond filter frequency?
This could be problematic if applied in several tracks!
Thank you!


Any news about this?
I also would like to communicate that the gain scale slider does not work when linear phase is active.
Thank you!


Hi Rufus,

We use a different Linear Phase algorithm in Pro-Q 2 which causes a bit more background noise. We'll investigate to see if we can improve this. In the mean time, I'd be interested to see any real-world examples where it actually becomes audible.

Thanks for letting us know about the gain slider in LP mode! We'll fix that in the next update.


Frederik (FabFilter)

I imageni that this new algorithm is made to consume less CPU by not focussing to much at values near silence that you consider far from the filter frequency. But in this images you can se that an increment of even 30 dB. In a single track this could not being audible. But in fact this tecnique used in several tracks can easily go beyond -144dB. This of course could save us from using dithering haha, but maybe some brute force would be awesome.
In fact I would like to answer you:
Should I use Pro-Q when I am using low cut and hight cut filter to obtain a cleaner sound?
Thank you very much!


Hi Rufus,

In our opinion you shouldn't go back to Pro-Q 1. The algorithm in Pro-Q 2 produces better results and I believe the background noise is inaudible -- but we're still looking into improving it.


Frederik (FabFilter)

Thank you very much Frederik and Fabfilter!


I would also like to add to this thread too. I noticed soundwise that ProQ2 sounds different to me than ProQ1. As in, I still use ProQ1 because my cuts and dips are much much cleaner. ProQ2 is good too, but I feel like ProQ1 still sounds cleaner to me. I think its because of these findings, my instincts have made sense.


In terms of "filter-self-resonance" Q2 is better than Q1, IMHO.

Also Q2 sounds even cleaner to me (im in linear phase mode). I do shelving for HP/LP. only if needed LC/HC but both sounds fine!


Martin Loecker

I still prefer using Pro-Q on the channel in zero latency mode because it is more transparent from Pro-Q2. When we have instrument on -25dB in the mix, and inserting the Pro-Q2 will cause that some very low level notes will disappear from highs if that instrument have some important details in the high's. But Pro-Q will not do that.
It is obvious that Pro-Q2 reacts on dynamic in the high's.
But Pro-Q2 is better in the Linear Phase Mode from Pro-Q.
However it is good to have both IMO.


Thanks for this topic. It makes me feel better. I recently over-paid for a second hand license of Q1 which resulted in the total upgraded price for Q2 being more than I can get it from the discount plugin online stores. I thought the guy was selling Q2 and I swear I looked and saw Q2 in the posting. after I paid and the transfer was made, I realized it was for Q1 and upon looking at the posting it said Q 1 so it must have been my mistake somehow.

I have read elsewhere about Q1 having a kind of transparency over Q2 and that is echoed in this thread. so perhaps it wasn't as bad of a disaster that I ended up with an expensive Q1 - if just upgrade it using the coupon in my account the price will be $164 vs $151 from the other online shops. but that would give be both for an extra $13. I guess that's ok.

Hopefully FF won't fix this in Q2 there-by sustaining some rationale for this erroneous purchase.


So I decided to try Equality again after few years, and the latest version I tried against Pro-Q2 I must admit on the analogue phase mode Equality is almost the same with Natural Phase on Pro-Q but with better transparency.
Actually latest version of Equality must be improved.

Equality have transparency how Pro-Q2 should have IMO.

But I belive FF will make it sound just like it should.



I am using Pro-Q2 v2.01, and after this version sound changed to less transparent in the Natural Phase and Zero Latency mode.
Is it possible to bring back this sound,and transparency again?


Hi Arg,

The sound hasn't changed since version 2.00, apart from a tiny bug fix in Analog Phase mode that would only happen in rare cases.

Floris (FabFilter)

We are not talking about the sound.
2.0.1 and 2.0.3 will null each other.
But Pro-Q2 V2.0.1 is more transparent from Pro-Q, and V2.0.3 is not transparent like Pro-Q V1.2.3.
They dynamically react different in the highs especially on lower parts of audio. Some filtering is going on in the high's on very low level audio.


If they null each other (I assume you mean that with inverted phase, duplicate tracks will cancel each other out), then how can one be more transparent than the other? By definition, they're the same right?


Frederik (FabFilter)

Yes. Probably they are identical I really did a small test with no extreme settings, but my point was on the Pro-Q-Pro-Q2 difference, and I change the topic to the Q2 versions without more exploring this matter. Sorry my fault.

But it could be really nice if we could have just identical zero latency mode from Pro-Q like add on mode to the Pro-Q2. Or we can use V 1.2.3 anyway. However new users will not have it.

Old zero latency mode is more focused (closer)(stereo), and transparent, really nice. New version is a bit wider (on stereo files) and not transparent as the previous version.


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