FabFilter User Forum

Fabfilter Pro-R2 Pre-Delay Tilt in Surrounds

Hi There

I recently got the FF Pro-R2. I was wondering about the functionality of the Surround Pre-Delay-Tilt function, because i like to ad a diffrent Pre-Delay in the Rears for Music than in the front channels. I startet to test the Pre-Delay Tilt with a 1kHz signal peep (one frame) on a 4.0 (L-R-Ls-Rs)track in PT to see how the Delay will affect my Rears. I got very confused because of the following experience:

A: When i add a 500ms pre-Delay without TILT it's working. The processed 1kHz reference tone will repeat after 500ms on all 4 channels.

B: When i tilt that 500ms predelay all the way to the Rears (Rears in this case should be Ls and Rs, right?), the processed 1kHz reference tone will be delayed around 130ms on all 4 channels, not delayed.

Shouldn't the L and R channel be processed without a delay and the Ls and Rs channel should have a delay of 500ms? What's the logic here?
I was expecting that the predelay tilt will put the 500ms delay only to the rears?

any experience or help for me?

thank you very much.

test settings:
Caracter: 0 / Thickness: 0 / Distance: 0 / Space: 0.20s / DecayRate 100% / Brightness:0 / Width: 0 / Ducking: 0 / Mix 100%

Maurizio Zulli

Hi Maurizio,

That's what we would expect as well. We'll test your scenario and get back to you.

Cheers,

Frederik (FabFilter)

Thank You very much! I appreciate.

Maurizio Zulli

We've analyzed the behavior on a Quad track. When you set the Predelay to 500 ms, and set Predelay Tilt all the way to the rear, you get 125 ms in the front, and 500 ms in the rear. The predelay doesn't go all the way to zero because we use the azimuth angle of the speakers and this is not zero for the front speakers. We could change this so everything from the front L/R speakers up to the center speaker is treated the same.

Can you confirm that you're getting 125 ms for the front L/R speakers and 500 ms for the rears though? Otherwise, please give us the exact channel layout that you are using in Pro Tools so we can look at that.

Cheers,

Frederik (FabFilter)

Hi Frederik

Thank you very much. I get 130ms in the L/R and 140 to 150ms in the rears.

Here is my Test session with a rendered File coming from the Pro-R2.
Download: we.tl/t-3tTjRERBME

The Routing is built as i would do it in a major movie session. My Goal is to feed a MONO or STEREO DRY signal (music, sound effect..) through a SEND channel to the Pro-R2 to create a 4.0 / 5.0 or bigger Reverb. I then want to adjust the Pre-Delay for the rear channels to be around 110ms and the front channels to be around 10-40ms to achieve a feeling of "sound is pulling through the room"

In the past i could achieve this effect with making two stereo reverb AUXs. On both AUX tracks the Pro-R was inserted but with slightly diffrent Pre-Delays (10-40ms & 110ms ). The AUX bus with the longer pre-delay was panned to the rear channels. I then feeded the DRY source signal with one SEND to both AUXs.

after I saw that the Pro-R2 has this tilt function, i was blown away, because this would make it much easier to handle.

Thanks for yur Help
Maurizio

Maurizio Zulli

Hi Maurizio,

Thanks for test session! I now see what happens:

  • You are only feeding the L/R channels of Pro-R 2, not the rear/surround channels.
  • What you hear/see in the rear channels, is the surround cross feedback of the L/R channels. This is delayed depending on the size of the virtual space. Since you chose a very small space, it only has a small additional delay.

At the moment, pre delay is only applied to the actual input of a channel, not to the potential surround cross feed inputs. We will think about whether we should change the behavior or not, but this might be challenging since it would affect existing sessions.

What you could do in your case, to get the behavior you're looking for is:

  • Send your stereo signal to all four channels.
  • Possibly customize (attenuate) Surround Cross Feed level to your liking.

I'm sure this will get you the desired effect! Let us know if this works for you.

Floris (FabFilter)

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