Trying to understand dBFS restrictions on an audio project

David-Rees wrote on 7/12/2022, 8:14 PM

Trying to understand dBFS restrictions on an audio project. The tech guy on the project has told me (at the last minute) there is a target level of -18 dB FS on sounds. I have moderately compressed sounds and have them at the volume levels all the creative members of the team want. Some of the sounds get as high as -14 dB FS. If I lower the volume 4 dB, they will not sound loud enough aesthetically. How do I go about getting sounds that are presently playing at the desired volume to fit the -18 dB FS rule that the tech guy is giving me?

Comments

rraud wrote on 7/13/2022, 12:11 PM

Hi @David-Rees, -18 dBSF is typically the EBU reference level based on a 1kHz or 400Hz test tone, once refereed to as 'digital zero' (as in 0 VU, way back when R-DAT recorders were introduced). Reference tones are not used much these days in terms volume levels for submission and streaming.
Most use the LU loudness unit scale. The EBU broadcast loudness spec is -23 LUFS (Integrated). In the USA, ATSC TV is -24 LUFS).. Not to be confused with dB (decibel) Any submissions outside that will likely be rejected.
-14 LUFS (Integrated) is the 'recommended' level) for music streaming and also should be at that level for submissions to music streaming services such as Spotify, TIDAL, Apple, Amazon, Pandora and Deezer., Out of spec submissions however will usually not be rejected like broadcast networks and just re-encoded with the loudness adjusted accordingly.,, Some services will boost or cut accordingly, whilst others will only reduce the level if it's higher than -14 LU, It is best however to get it the loudness right so it will not have to be re-encoded, reducing the overall quality. You can also check your music file levels at Loudness Penalty.com. All the streaming services are within two or three LU units of the -14 LUFS standard. For narrative videos (streaming and optical media), the LU is slightly lower at -16 to -18 LU. The ACX audio book spec uses the dB RMS scale and must be within -18 to -23 dB. Full scale dB and RMS dB are quite different, as is the (LU) loudness..
There is much information on the internet.. search and read. If you are submitting programs for broadcast, download the EBU (or ATSC) submission specifications and have a full understanding of the LU audio parameters (integrated, true peak, short-term, momentary and range) beforehand.

Sound Forge has many meter scale readings, dBFS (peak) being the most important in the recording and editing stage where 0.0 dBFS is the absolute highest level, and anything over that will be clipped (distorted), Use the LU loudness (or other depending on the destination) for the final levels in the mastering stage
FYI, Sound Forge Pro has a "Statistics" tool to quickly determine the LU factors, so the entire duration will not have to be checked in real-time.

johnebaker wrote on 7/13/2022, 12:23 PM

@David-Rees

To add to @rraud comment regarding the EBU R 128 loudness levels, there is the Youlean loudness meter which several users here, including my self, use for video, the loudness meter also works with audio programs that support VST's, it can be also be used standalone.

HTH

John EB
Forum Moderator

David-Rees wrote on 7/13/2022, 6:51 PM

Excellent. I installed Youlean and found it really useful.

browj2 wrote on 7/13/2022, 7:16 PM

@David-Rees

Hi,

Here is a very good tutorial explaining how to use YouLean:

John CB

rraud wrote on 7/14/2022, 11:03 AM

The ToneBoosters EBU loudness meter is also nice and offers more info and settings (which you may or may not want or need) than the Youleen. In addition to the usual loudness factors, the TB meter includes a 'Gate state. Peak-to-loudness ratio and VU/VU peak hold'. It also has the ATSC mode and others, It has been discontinued, so it is is now free along with TB's other discontinued products.

johnebaker wrote on 7/14/2022, 1:11 PM

@rraud

Hi Rick

Have you a download link for the ToneBoosters EBU Loudness meter - everything I am finding goes nowhere, or is no longer available.

John EB

rraud wrote on 7/14/2022, 1:52 PM

Hi @johnebaker, I have not tried it, but go to https://www.toneboosters.com/changelog.html and choose one of the Windows portable downloads with the legacy plugins. I think that should have the <.dll> files for the discontinued plug-ins to paste to a VST folder. If that does not work, let me know and I can post the 32 bit VST-2 version file which works fine in SF. I do not use the TB meter much and usually rely in SFP's 'Statistics' tool.. faster and easier. The TB meter has a real nice display though.

Update: Download the "Windows portable v1.6.2 (current and legacy plugins; 64 bits)" from the above link. Exact the Zipped files and find the "TB EBU Loudness meter V3" in the VST-2 64 bit 'Bus Tools' folder. Copy the EBU meter <.dll> file and paste it into one of your 64 bit VST-2 folders.
As I previously stated, I also have the old 32 bit VST version if you want it

johnebaker wrote on 7/14/2022, 2:38 PM

@rraud

Hi Rick

Thanks for the link, testing now.

John EB