phase parameters for broadcast

AGM · 13th January 2012

Hello. I'm wondering if anyone had any idea of a generic guideline or suggestions re. broadcast QC and phase. I've been playing around with the waves dorrough meter on a 5.1 music mix and I'm noticing that I'm getting occasional phase errors. Looking at the phase meters, there are minor excursions into the -21 to -23 zone which set the error notifier off. Does anyone have any suggestions as to where you consider the phase to be heading into the danger zone with a deliverable? Where does your meter dance? What would you say a (reasonable) broadcaster QC fella would find acceptable?

On a side note, the mixes are fairly conservative - no widening effects etc. Voice down the center, musical inst = L/R with a bit bleeding to the Ls/Rs. It is translating perfectly to stereo and mono. If I hadn't seen the error on the dorrough, I likely would have not questioned the mix.

Other side note: I am able to prevent the phase error from happening by pulling in various elements to the center a bit but it's a total bummer as the tracks are sounding great spread out. Super great.

If there's anyone out there that can share the knowledge, I'd be grateful!

Thanks!

-AGM

georgia · 17th January 2012

Have you listened to the mix in MONO? The real issue here is anything that has a phase problem is going to turn into phase cancellation issues and your mix is going to sound different. So check the mix, does it sound "the same" in Mono or are portions of the mix disappearing, getting louder or quieter? If it sounds good in stereo and in mono you're probably good to go.

The other side of the question is what are the delivery specs? Delivery specs for broadcast vary widely.. I keep an entire 3 ring binder with specs from a number of broadcast clients... Take a look at the specs and make sure you are meeting them.

The bottom line here is you need to meet the specs given you for deliver. If it affects the mix adversely in your opinion,well, welcome to the club. Make it sound as good as it can and meet the delivery requirements your client is paying you to meet.

A number of specs simply state that tracks must be "in Phase". So that is more of a call on your part as long as you don't go overboard with wild phase issues in the music and ambience, and you keep the dialogue in phase. An occasional phase bump is not the end of the world, but again, make sure to monitor in MONO as part of your QC routine.

cheers
geo

AGM · 20th January 2012

Thanks Georgia. This is exactly the type of advice I was hoping to get. I've always double checked mixes in mono so all is good there. I've also been adhering to the broadcaster's specs. Much like the example you cited, this broadcaster just stipulated that he sound be "in phase". It seemed a bit vague and you cleared it up for me. I submitted some test mixes (as is) to the QC department and heard back that everything falls into spec and that they are happy.

Thanks again,

AGM

huub · 20th January 2012

When we used to broadcast live some programs in prologicII, we would every once in a while get a warning from MCR saying our left and right were a bit much out of phase.
This is of course a consequence of dolby stereo encoding. Basically you can be as much out of phase as you wish, as long as the mono is what you want it to be (and as long as the mono has a healthy level.)

13th January 2012	#1
AGM Gear Head Joined: Oct 2008 Posts: 36 Thread Starter	phase parameters for broadcast Hello. I'm wondering if anyone had any idea of a generic guideline or suggestions re. broadcast QC and phase. I've been playing around with the waves dorrough meter on a 5.1 music mix and I'm noticing that I'm getting occasional phase errors. Looking at the phase meters, there are minor excursions into the -21 to -23 zone which set the error notifier off. Does anyone have any suggestions as to where you consider the phase to be heading into the danger zone with a deliverable? Where does your meter dance? What would you say a (reasonable) broadcaster QC fella would find acceptable? On a side note, the mixes are fairly conservative - no widening effects etc. Voice down the center, musical inst = L/R with a bit bleeding to the Ls/Rs. It is translating perfectly to stereo and mono. If I hadn't seen the error on the dorrough, I likely would have not questioned the mix. Other side note: I am able to prevent the phase error from happening by pulling in various elements to the center a bit but it's a total bummer as the tracks are sounding great spread out. Super great. If there's anyone out there that can share the knowledge, I'd be grateful! Thanks! -AGM

17th January 2012	#2
georgia Lives for gear Joined: Dec 2006 Location: NY NY Posts: 1,331	Have you listened to the mix in MONO? The real issue here is anything that has a phase problem is going to turn into phase cancellation issues and your mix is going to sound different. So check the mix, does it sound "the same" in Mono or are portions of the mix disappearing, getting louder or quieter? If it sounds good in stereo and in mono you're probably good to go. The other side of the question is what are the delivery specs? Delivery specs for broadcast vary widely.. I keep an entire 3 ring binder with specs from a number of broadcast clients... Take a look at the specs and make sure you are meeting them. The bottom line here is you need to meet the specs given you for deliver. If it affects the mix adversely in your opinion,well, welcome to the club. Make it sound as good as it can and meet the delivery requirements your client is paying you to meet. A number of specs simply state that tracks must be "in Phase". So that is more of a call on your part as long as you don't go overboard with wild phase issues in the music and ambience, and you keep the dialogue in phase. An occasional phase bump is not the end of the world, but again, make sure to monitor in MONO as part of your QC routine. cheers geo __________________ ms georgia hilton mpe(editor) mpse cas NY NY http://www.filmdoctors.com http://www.hiltonmediamanagement.com http://www.hmmproductions.com http://www.editingtruck.com http://www.stage32.com/profile/6569/georgia-hilton http://www.imdb.com/name/nm0385255/resume MEMBER: IATSE LOCAL 700

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20th January 2012	#3
AGM Gear Head Joined: Oct 2008 Posts: 36 Thread Starter	Thanks Georgia. This is exactly the type of advice I was hoping to get. I've always double checked mixes in mono so all is good there. I've also been adhering to the broadcaster's specs. Much like the example you cited, this broadcaster just stipulated that he sound be "in phase". It seemed a bit vague and you cleared it up for me. I submitted some test mixes (as is) to the QC department and heard back that everything falls into spec and that they are happy. Thanks again, AGM

20th January 2012	#4
huub Lives for gear Joined: Apr 2005 Location: amsterdam Posts: 1,207	When we used to broadcast live some programs in prologicII, we would every once in a while get a warning from MCR saying our left and right were a bit much out of phase. This is of course a consequence of dolby stereo encoding. Basically you can be as much out of phase as you wish, as long as the mono is what you want it to be (and as long as the mono has a healthy level.)