Phasing issues?

[tobbenos]

Hi, guys.

I'm setting up my own "free" multi-band compressor (sending a tracks signal to four aux channels, applying EQ's with low- and high-pass filters).

On the original channel, I'm sending signal to the multiband through a send, not just the channel output. This way, it will be a parallell compression.

The high- and low-pass filters (at the moment, I'm using the Channel Strip) are all wit 24 dB/oct settings, with cut-off frequencies as follows:
Channel 1: Lows. Low-pass: 120 Hz
Channel 2: Low mids: High-pass: 120 Hz, Low-pass: 1.5 kHz
Channel 3: High mids: High-pass: 1.5 kHz, Low-pass: 5 kHz
Channel 4: Highs: High-pass: 5 kHz

When I'm sending signal to the multiband setup, at the same time as letting sound out from the original track, I get something that sounds like comb filtering. The delay compensation display shows that no delay is introduced. When I mute the original track, everything sounds normal. I guess this would indicate phase issues, but where would they come from when no delay has been introduced?

I have been thinking that a bypassed plug-in (not inactivated) introduces the same amount of delay as an active plug-in. I therefore tried putting the same plug-in (Channel Strip) on the original track, and bypassing it. However, I still got the comb-filtering. I then tried bypassing the plug-ins on the multiband channels, and that eliminates the filtering! If a bypassed plug-in introduces the same amount of delay as an active, this would indicate that it was not phasing issues, but maybe something with my cut-off settings. However, when I'm muting the original track and only getting signal from the multiband channels, the sound is normal. So I'm back to start again.

Have any of you an idea of what I (or a plug-in) might be doing wrong?

[tobbenos]

Does nobody know what might be going on?
Is there anyone with some time to spare, being able to recreate the problem?

[albee1952]

The action of multi-band compression is causing EQ changes, so phasing is an expected byproduct of this method. Any time EQ changes between 2 paths of the same audio, you will get phasing as EQ induces phase shift(some EQ's are better, some are worse, but all will do it. Process audio THRU the plugin only, not in parallel mode.

[tobbenos]

Thanks a lot for the reply.
However, why does the phasing also happen when all the EQs on the multi-band tracks are bypassed? That's what making me curious..

[albee1952]

Originally Posted by tobbenos

Thanks a lot for the reply.
However, why does the phasing also happen when all the EQs on the multi-band tracks are bypassed? That's what making me curious..

Its a good question for sure. You might want to have a look at a video at airusersblog and watch Russ do multi-band compression with the AIR Kill EQ. In any case, you might be better off using the real thing. I wonder if Waves sells the C6 as a single plugin?

[spearson]

If you are using PT9 or 10, turn your auto-delay compensation on. If you don't have auto-delay compensation, you're kind of screwed unless you put your sends in pre-fader mode and then throw time-delay plugin's on your track.

[TOM@METRO]

Originally Posted by albee1952

I wonder if Waves sells the C6 as a single plugin?

Yes they do. And it's on sale.

[danander11]

Have you tried using a linear phase EQ?