Trying to understand dBFS restrictions on an audio project

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?

Hi giga…

A few guys here at my studio have been talking about this question and we would also be perplexed if someone asked that with no further information or we are missing the context it regards.

My answer may be way left field. But it would great if this person could clarify what he is talking about.

Here is the some of the times -18dbfs or levels is generally discussed…

1. -18 is commonly (but not always) used as a starting level for tracks in the digital age. Commonly known as gain staging. See the attached picture where I set each track to -18 prior to starting a mix. This is not a hard and fast rule but its good practice.
2. If you are referring to the level of a completed project. Most people use LUFS to commonly set levels of tracks. This is mostly useful for streaming services OR broadcasting radio levels. example is the EBU128 rule for television, radio etc. In the picture you see I am looking at the LUFS of a project.

An example is my mastering engineer may return one of my projects back to me with a LUFS of -9 with an occasional -8LUFS. I may have sent him a premastered mix at -6 dbfs.

Additionally, you can see in this picture that there is the option to set the loudness meter to -18LUFS. So they may also be talking about that.

It needs to be noted that dbfs and LUFS are not the same. Seen here that -18dbfs on my master track produces a different LUFS number.

I’m hazarding a guess this person talking about gain staged tracks. Apart from that. I would need more information.

A simple question may be?
What do you want to be -18dbfs.
Each track?, each stem? each Bus? Gain staging? Master volume?



It is also worth noting that when people talk about gain staging to -18dBFS, we are talking about RMS value, not sample peak level as measured by a common DAW channel meter. Usually this is used in conjunction with a VU meter (like in Supervision, but be sure to set the scale to “VU dbFS”) which is calibrated to -18dBFS so that 0VU = -18dBFS RMS, to properly gain stage track levels for use with e.g. analog emulation plugins that are calibrated to exact this value.

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There is no dBFS restrictions on digital domain. With 32 bit fp processing you may go to + as well as - dBFS
If we’re talking about gainstaiging for analog outboard (or, at least, some analog emulation plugins) to work properly - there is another question

Thanks very much. More context… the project involves creating individual UI sound fx (bleeps, chimes, marimba tones, blips) which get played back individually on a small custom hardware device with a specific amp and speaker. The final sounds themselves must be -18 dbfs. The creative members of the team are happy with the quality of the sounds and the playback volume, but the tech team members are requiring -18 dbfs. The sounds presently are more like -14 to -12. The challenge is to meet the -18 dbfs requirement without significantly lowering the playback volume or the quality of the sounds themselves. I am thinking this will require a combination of compressing the sounds more (to lower max peaks) and slightly lowering the volume, and try to find a sweet spot that doesn’t sound significantly different from the aesthetic experience the team is happy with. I am not that nuanced with compression techniques, so finding this is a little challenging for me. Thanks so much for your response. I am learning a lot.

So if we assume that with “-18dBFS” they mean peak level (and not e.g. RMS), there are two options:

  1. Normalize to -18dBFS, which will of course lower the volume, but the sounds will stay the same. If the sounds should be louder on the playback device, they need to increase the level of the amplifier there.
  2. Limit the sounds to max -18dBFS with a brickwall limiter (not a simple compressor). Alternatively, for very sharp percussive sounds, a clipper can be a good option.
    Depending on the sound, a combination of decreasing the level and limiting could be required, say if the limiting/clipping produces unwanted artifacts.
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Thanks. This seems to be working. Appreciate the help.