Duplicated track not cancelling when inverting phase...

[rcd]

We've noticed some phase issues so performed a duplicate track phase inversion and the 2 identical tracks are not phase cancelling (when one of the phases is reversed). What are the possible culprits of this issue and what needs to be done to fix it please?
Thanks in advance for any info.

PT12HD Native
Windows 7
Avid HD i/o 16

[crizdee]

Originally Posted by rcd

We've noticed some phase issues so performed a duplicate track phase inversion and the 2 identical tracks are not phase cancelling (when one of the phases is reversed). What are the possible culprits of this issue and what needs to be done to fix it please?
Thanks in advance for any info.

PT12HD Native
Windows 7
Avid HD i/o 16

any plugins on the tracks or just pure identical audio? Plugins that modulate will effect cancelation but not stop it totally.

Is it cancelling at all or is nothing happening. Identical audio with the same phase will just get louder.

Chris

[midnightrambler]

Timing (e.g. audio in wrong place / different latency on plugs)
Different volume levels
Different EQ
Different FX (esp modulating ones such as chorus etc as mentioned above)
Different Compressor

Er....anything else?

[SOUNDDECISION]

What plugin is being used to invert the phase?

Do you have the same plug in on both tracks? (one not inverted)

Do you have ADC turned on?

[midnightrambler]

I've compared mixes printed offline vs online and found that there can be very small discrepancies with some VIs, e.g. Battery, where the sounds won't entirely cancel as they are a few samples out.

[john1192]

i find if there is a modulation on a plugin it could happen Because, the modulations are not uniform .. like a phaser on guitar does not do the same thing twice ..

maybe ??

[rcd]

Thanks for all the replies! I tried the cancellation test using the Avid/Digi Eq Plugin and again tried is by inverting the identical track via 'options' and 'render' (I think, was an all-nighter last night)...
I'll try placing the same plug on the other track since I only had the one plugin inserted, there were no other plugs on either track.
I'll report back after I fire up today!
Thanks!
Rich

[Postman]

Avid/Digi Eq Plugin

Yes, it is true. Latency through some types of EQ3 are not the same when phase is flipped. Probably a bug. I've noticed it from time to time since PT10.