Understanding peak audio levels

[John Fishback]

As these specs vary, it’s always best to ask your client what their delivery specs are.

John

MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.5 QT7.5.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 2 (FCP 6.0.5, Comp 3.0.5, DVDSP 4.2.1, Color 1.0.3)

Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN

[Alan Smith]

This is generally defined by the network broadcasting the show, not the producer who produced the show. We produce shows that air on two different networks and have different requirements for peak levels. One network requires -20db tone and allows peak levels to hit -6db. The other network requires -20db tone but limits peak levels to -10db with normal voice levels bouncing at/around -20db. So, levels for broadcast are largely defined by the network and they have production guidelines that you can obtain.

Alan Smith
Media317

Check out my blog – https://media317.com

[Wesley Dysart]

So there would potentially be different master tapes for different networks depending on their required specs? That makes sense I suppose. So if a client were planning on sending out many copies of a master tape the burden would be on them to provide the right specs to us. If we knew the networks they were using we could double check the specs with each network.

Thanks for the help guys, I get a lot of on-the-job training but I try to supplement that with my own research. So far this forum has been very helpful.

-Wesley D.

[John Fishback]

I’d definitely double-check. If the master isn’t in spec, it will be rejected by the network’s QC dept.

John

MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.5 QT7.5.5 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 2 (FCP 6.0.5, Comp 3.0.5, DVDSP 4.2.1, Color 1.0.3)

Pro Tools HD w SYNC IO, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN

[Terry Mikkelsen]

Don’t confuse tone with peak levels.
Tone was set at 0VU in the analog days. You can have program audio louder than 0VU and it is natural to do so. Analog also had an inherent compression attribute with tape saturation.
When we moved to digital, there is no compression to the format when you exceed its maximum abilities. So, it was determined to lower the average level to allow some headroom in the program levels. This became a highly subjective issue. There is no absolute (except as those determined by each house) and so that is why you see different specs.

So it breaks down like this:
1. Find out what your final delivery format is and what levels they require (both average or tone levels and the maximum).
2. Lay your tones at the appropriate level. Lets say -16dBfs for this example. Now you know that if you need to goto analog for some reason, you will have -16dBfs on your digital machine and your analog needs to get set to 0VU.
3. Adjust your speaker volume to a comfortable level while listening to your -16dBfs tones.
4. Without adjusting your speakers, adjust your program volumes to be roughly the same comfortable volume that your tones were.
5. Now scan through your program and make sure you do not exceed the maximum level specified by your final house. (If needed, add some gentle compression and/or limiting)

ps I like RMS Buddy for level monitoring

pps I prefer -1dBfs for CDs

Tech-T Productions
http://www.technical-t.com