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No LM100, what to do?
Old 12th November 2009
  #1
Gear Maniac
 
Jussi's Avatar
 

No 737, what to do?

Were mixing an advert for cinema, it's an odd freebie, but the problem is that we don't have an LM100 in the theatre, altho it is a Dolby room. The budget is tight, there is no money to rent the LM100 unit or go to a room where LM100 is present - my hands are tied.

Anyway we have a deal with Dolby to send the mix in there, they check it and then ask for adjustments for us to make to meet the Leq 82. This process will be very random, and in order to make it less painful I'd love to know is there an alternative method of measuring the leq82, even roughly, so that we are not shooting completely in the dark. Thanks!

EDIT:
Fixed topic name: by LM100 I of course mean 737 Loudness meter (Leq(m)
Old 12th November 2009
  #2
Gear Maniac
 

Phasescope in protools does Leq(A) and this: (free - Windows only)
ORBAN Loudness Meter
does the ITU.BS.1770 (Leq (RLB2))

Mult a fixed-level digital out from your mixer to a laptop running whatever's necessary and measure away with pretty good confidence. Remember that summed mono on a LM100 will be +3db when looking at these stereo meters.

Other options for the BS.1770 include using the 14 day trial of TC LM5D (PT HD)
TC Electronic | LM5D

Those are all the "free" ones I can think of.

Last edited by Loki; 12th November 2009 at 07:05 PM.. Reason: added more options
Old 12th November 2009
  #3
Gear Maniac
 

I think what you really need is a meter which reads Leq(m) like the Dolby 737 or equivalent. The LM100 won't give you a reading of 82; it's reads backwards from full scale. i.e -27. The 737 gives you positive numbers (that relate to spl I think). The curve is also a little different than an Leq(a) or the BS.1770. IIRC It has a peak in the midrange and is called the "annoyance curve".

I think one of the DK meters has an Leq(m) option too.

-Richard

p.s. http://www.dolby.com/uploadedFiles/z...el737.Spec.pdf

Last edited by rhumphries; 12th November 2009 at 07:10 PM.. Reason: added link
Old 12th November 2009
  #4
Gear Maniac
 

The LM100 only does Leq(A) and ITU-BS.1770 so if that's what it's going to be measured on he should look at the plugins I suggested. The 737 (Leq(m)) doesn't help (that's quite a different weighting curve.)

I do agree that the positive numbers vs neg numbers confused me from the OP. I'm the wild guess of 82 = -23 based on SMPTE = 85dbC = -20dbFs
Old 12th November 2009
  #5
Gear Maniac
 

Quote:
Originally Posted by Loki View Post
The LM100 only does Leq(A) and ITU-BS.1770 so if that's what it's going to be measured on he should look at the plugins I suggested. The 737 (Leq(m)) doesn't help (that's quite a different weighting curve.)

I do agree that the positive numbers vs neg numbers confused me from the OP. I'm the wild guess of 82 = -23 based on SMPTE = 85dbC = -20dbFs

Loki, I agree with you, but he said he was doing an Ad for cinema & the mention of the positive number made me think Leq(m). I don't mix cinema trailers so I could be wrong, but isn't Leq(m) still the standard measure of loudness for cinema trailers/ads?

-R
Old 12th November 2009
  #6
Lives for gear
 
Kuba_Pietrzak's Avatar
 

Yeah, for Dolby Digital ads are 82Leq(m) and trailers are 85Leq(m).

I wonder, what the requierments for Digital Cinema are, as there is no Dolby Digital involved anymore...

Kuba

PS. Dolby room without Dolby (cinema) meter?
Old 12th November 2009
  #7
Quote:
Originally Posted by Kuba_Pietrzak View Post

Kuba

PS. Dolby room without Dolby (cinema) meter?

Dolby does not require an LM100 to approve a room for Film Mixing. All the Dolby gear that is required in the States is a DMU, which is provided by Dolby.

There are a lot more requirements for an overseas Dolby Approved room, including a Cinema Processor, but an LM100 is not on that list either.

cheers
geo
Old 12th November 2009
  #8
Gear Maniac
 

R, your right. I belive the OP is on the wrong track with the meter to use.

According to the CAC
http://www.cinemaadcouncil.org/docs/...kbsof0wtrk.pdf

"Additionally, on the source/production side, the recommended average sound level of rolling stock advertisements shall be 82 decibels (based on the LEQ(m) loudness measurement)."


So that would be measured with the Dolby 737 at 82.
Old 13th November 2009
  #9
Lives for gear
 

Quote:
Originally Posted by Jussi View Post
Were mixing an advert for cinema
Use a Dolby 737 and mix to 82 Leq(m).
Old 13th November 2009
  #10
Gear Maniac
 
Jussi's Avatar
 

Sorry guys, I seem to indeed mixed the meters up. 737 is the one. Anyway, we do not have that one in the rack either, so the question remains.

Thanks for all the answers so far.
Old 13th November 2009
  #11
Hi Jussi,

Maybe this could help:

AudioLeak

Channel D Software Download Page
Old 13th November 2009
  #12
Lives for gear
 

Audioleak is nice, but it will not give you an LEQ(m) measurement.
Old 14th November 2009
  #13
Lives for gear
 

Quote:
Originally Posted by smurfyou View Post
Audioleak is nice, but it will not give you an LEQ(m) measurement.
No it does not and it can lead you significantly astray if you assume it does. If your contract specifies a real dialnorm figure you should try to figure out a way to get a read from a real LM100 or Dolby Media Meter, since that is what the QC people examining your mix will use. Anything else is a guess.

Philip Perkins
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