LtRt Tone

[Newpostguy]

Hi,

I made an LtRt Mix recently and put -20 db of tone on all 6 channels and set it to read -20 once DECODED by the PL II decoder. Was this wrong?

The mastering house tells me it reads at -14 and has checked in multiple places. I mentioned it should read -20 in the decode and they said they do not deal with dolby encode / decoded stuff other than dolby E.

What should I do to make things smooth here? Was my first LtRt that went for layback outside the studio.

Thanks guys!

[Postman]

Where on earth did you get that procedure?

Reference the tone to left and right channels only. -20 on left and right (no center or surround) should encode to -20 on each channel of the LtRt. That is all you need to worry about. Truthfully, I often start a mix with tone straight out of PT's Audio Suite Signal Generator. I just print -20dbfs to a stereo track and continue recording my mix after that.

It sounds like you should just remake the tone and tell them to ignore the one you attached originally. Or better yet, resend the whole LtRt with the proper tone.

While I see the possible logic of making tone the way you did, and it would be correct for Dolby E or Dolby Digital, it is not the right way for the analog LtRt format. LtRt is essentially a stereo file and is essentially treated as such.

[Newpostguy]

Thank you Postman.

I would like to send you a bottle of wine. You have been my guiding light throughout some dark times!

I popped in the tone simply to L and R and consolidated the region with the rest of the encoded mix.

As far as why did I do it that way? A combination of misinformation and lack thereof. I will try to find the thread that told me I needed to do this. Can't remember if it was here or on the slutz.

P.s. I have always been nervous about punching into a mix and consolidating the region. Is there anything wrong with this? Been getting away with it lately. Wondering if my doubts are justified?

[mr.armadillo]

Originally Posted by Newpostguy

P.s. I have always been nervous about punching into a mix and consolidating the region. Is there anything wrong with this? Been getting away with it lately. Wondering if my doubts are justified?

If you just replace the tone, you shouldn't be nervous about doing so and consolidating the region. However, there where some pop- and click-issues with punching in on destructive record (which is the more elegant way of doing it than "consolidate"), but if you set some pre- and post-roll time and mind the reverb tails, this shouldn't really be a problem.

[Newpostguy]

oo I like elegant. Will try that! Thank you soooo much everyone. Im really starting to feel confident with my work. (for a moment lol)

[Postman]

I would like to send you a bottle of wine.

Thanks but no need, because I'd probably have sucked it dry before it even got delivered, thus it would have fallen into a time warp and never happened.

BTW. one trick I like is that you can use AudioSuite to overwrite the old tone. No need to consolidate anything.

[Johnny2Laps]

FYI

I don't use destructive record and do use consolidate regularly; no problems.

I don't use destructive because I always want to be able to "undo".

[tigas]

Just to nitpick: the reference is -17dBFS to the Center channel - after encoding, if your encoder is calibrated, it should give -20dbFS in each Lt/Rt channel.

[mr.armadillo]

Originally Posted by tigas

Just to nitpick: the reference is -17dBFS to the Center channel - after encoding, if your encoder is calibrated, it should give -20dbFS in each Lt/Rt channel.

That's correct. Or, somewhat simpler to remember: just send -20dBfs tone to the left and -20dBfs to the right input of the encoder. Which is was Postman said.

[Postman]

the reference is -17dBFS to the Center channel - after encoding, if your encoder is calibrated, it should give -20dbFS in each Lt/Rt channel.

That works just as well, and elegantly gets around the fact that Pro Tool's Signal Generator cannot make a proper realtime stereo tone, because left and right are not phase locked. You can audiosuite tones onto multichannel tracks properly, but a multimono signal generator in realtime is bad bad bad.