Mixing to low levels and boosting Master output to unity(meters) the-same as mixing to unity(meters) in DAW?

[canidoit]

Hi,

Is this true, that in the digital realm of the DAW that creating a mix to lets say -20 on the master output(meters) and using gain to boost it to unity on the master output produces exactly the-same results as mixing to unity on the master output(meters) to begin with? I am using Logic DAW.

The reason I ask is because I have a few mixes where I mixed it way too low and I was told that in the digital realm, once it is recorded properly into your DAW, normalising, gain adjustments produces the-same results.

I did a test and I noticed that when mixing to unity, my final mix seems to be slightly harsher that when on the-same mix, I was mixing to low master level(ie. -20) and boosting gain at the master fader to reach unity. I adjusted the listening levels to be the-same in the comparison. I am still unsure as to whether it has become harsher because it is not the-same mix as I may have adjusted each channel not equally?

Another question is, if I was to raise all my channels by 5 on the faders in a mix, is it correct to say, that 5 raised on each channel fader regardless of where it starts produces the same loudness?
For example;
Kick is at -20 and raised to -15 on the channel fader.
Snare is at -5 and raised to unity 0 on the channel fader.
With all the other channels raised by 5 in a context of a mix, would that produce the-same audio quality as if I mixed that loud to begin. ie. bass, mids, treble relatively equal? I presume that things like harmonics from plugins would not matter in this situation as I am only raising the output of the result of each channel.

Thank you.

 

[john12ax7]

It's possible that with the higher level mix you are getting some internal clipping, either the DAW mixer, or some plugins causing the harsh sound. Theoretically this shouldn't happen with a modern floating float engine, but not everything is coded to the right standards.

It is also better practice to mix ITB at lower levels in general. Noise floor isn't an issue, and somewhere around -20dBFs to -16dBFs would be equivalent to +4 analog standard. Some plugins will actually model this and therefore sound better. Imagine hitting your 1176 at +20 input, that might get harsh too.

In short mixing ITB at lower levels will probably give you better results. You could consider changing your DAW metering if that's an option. I've found the Bob Katz K style metering to be very useful.

 

[Ricardus]

Dave Rat on his youtube channel is exploring these kinds of questions. He does lots of videos on this sort of thing.

 

[JohnRoberts]

are meters dBFS or dBu? -20dB FS is pretty much 0VU

JR

 

[AlgoRhythms]

A small but important point to consider when adjusting a mix level after it's done.

If you raise or lower the level of a digital mix file, you'll expand the wordlength, if it's a fixed point file. This will happen if you change by .1 LUFS or 20 LUFS. Your wordlength will expand.

So one has to decide whether to dither or truncate back to the original wordlength after that gain adjustment if you need to deliver the new work at the original wordlength.

Not really an issue with a float type of file.

 

[athnony]

In theory it shouldn't change your mix, but I think john12ax7 is correct overall. Maybe try a null test between your unity mix vs. -20 mix.

What are you using to boost your gain up on your master? Sometimes those plugins can color a mix, especially if you really push them. I usually send a post + pre limiter mix to my mastering engineers since they'll occasionally prefer to work with the limited version.

 

[AlgoRhythms]

The null test is an excellent idea.

 

[abbey road d enfer]

As athnony wrote, "In theory it shouldn't change your mix". However, if there is any dynamics processing in the mix bus, something will change.

 

[ubxf]

isn't mixing at lower level reduce the bit rate ?

 

[abbey road d enfer]

isn't mixing at lower level reduce the bit rate ?

No. The bit rate is the same, it's determined by the system's sample rate and bit depth.
Indeed there was an issue when DAW's operated in fixed point.
Mixing at low level reduces the Dynamic Range, since it avoids hitting the Most Significant Bits. It is equivalent as reducing the system's bit depth. So a 24-bit system would be actually operating within a 21 or 22 bit range.
Most DAW's operate at 32-bit floating point today. The Dynamic Range is about 240dB and the precision about 0.1ppm (party-per-million) almost independant of level within the DR limits.

 

[Gold]

It is equivalent as reducing the system's bit depth. So a 24-bit system would be actually operating within a 21 or 22 bit range

20-21 bits is about at the practical limits of analog circuitry. That’s about all you will get out of even the best A/D converter.

 

[abbey road d enfer]

Converters operate at fixed-point. It means that operating at -18dBfs results in irrecoverable loss of 3 bits
32-bit float has one bit for sign, 24 bits for the significant number, and 7 bits for the scale, where each value represents 6dB gain or attenuation.
Mixing in 32-bit floating point at reduced level, for example at -30dBfs, changes the scale at which the ALU works but the resolution is always 24 bits.
In theory, mixing at -700dB would allow perfect lossless recovery of signal. Most DAW's do not allow that because it doesn't make sense in the constext, where even 100 tracks running at 0dBfs result in only about +30dB overflow.

 

[EarthTone]

I can tell you after a lot of trial and error that mixing at lower levels has generally worked a lot better for me in the digital realm. It's also good to treat your DAW like an analog console for the reason which is that if you want to bring in some analog hardware in a hybrid digital/analog mixing environment, everything will already be gain staged and you won't have problems trying to fit in the hardware level wise. Imagine crushing your DAW meters with level and then trying to run a guitar solo through your 1176 and hoping to get it loud enough to match. You'll likely clip the hardware and/or your converters on the way back in.

You can either setup one big VU meter on the stereo output and watch that, mix into it, or you can put VU meters on the top of every track. Or you can setup your colorfades on your meters to work like VU meters sort of, so that you get green around -infinity to -12dbFS, yellow until around -6dbFS, and red above that. Like this:

I do a mixture of both. Trying to get away from the VU plugin on the top of every chain and just rely generally more on the colored metering and changing the input trim gain of the top of the channel. Keep in mind this will affect the level hitting any plugins or hardware in the chain so I like to do this 1st before panning and general levels so I don't have to mess around with it later and change compression/saturation settings based on input level changes etc.

Plus your mastering engineers will love you! They generally don't want not mixes to work with.

 

[john12ax7]

Most DAW's operate at 32-bit floating point today. The Dynamic Range is about 240dB

Where are you getting 240dB? The effective dynamic range of floating point is governed by the mantissa, which is 24 bits.

 

[abbey road d enfer]

Where are you getting 240dB? The effective dynamic range of floating point is governed by the mantissa, which is 24 bits.

Sorry, I made a mistake. The actual DR is 1528dB.
https://www.sounddevices.com/32-bit-float-files-explained/In practice DR is limited by analog circuitry.

 

[JohnRoberts]

1528 dB is a lot....

JR

 

[ubxf]

No. The bit rate is the same, it's determined by the system's sample rate and bit depth.
Indeed there was an issue when DAW's operated in fixed point.
Mixing at low level reduces the Dynamic Range, since it avoids hitting the Most Significant Bits. It is equivalent as reducing the system's bit depth. So a 24-bit system would be actually operating within a 21 or 22 bit range.
Most DAW's operate at 32-bit floating point today. The Dynamic Range is about 240dB and the precision about 0.1ppm (party-per-million) almost independant of level within the DR limits.

Thank you, i just remember years ago when i was using 16bit hardware samplers and playing back 4 octaves down .
Things have changed a little since then : )

 

[Gold]

Not to be a pedantic jerk but 0dBfs in not unity gain. There is no fixed relationship between analog levels and digital levels. Like has been pointed out earlier you can define 0 reference level however you wish. -18 and -20dBfs are popular for tracking and mixing.

Since the level usually gets slammed for release, mastering reference levels are usually more like -16 through -8dBfs.

 

[abbey road d enfer]

Indeed 0dBfs is not a gain, it's a digital level. And of course the relationship between digital level and electrical level is arbitrary, depending on the designer's choices and the systems resources.
In fixed point sytems, 0dBfs is the absolute maximum level that can be handled by the system, it's 100%.
In floating point systems, where the possible Dynamic Range is enormous, the nominal 100% level is actually about 700dB below the absolute max, right in the middle of the 1500+dB range). It allows mixing and processing a very large number of tracks without any risk of overflow.
It is overengineered for most audio applications, but floatin-point digital is a mathematical concept that is used in many other sciences, where the DR can be challenged.

 

[john12ax7]

You don't actually get 1500 dB dynamic range with 32 bit float as you can't simultaneously resolve very strong and very weak signals. You are limited by the epsilon error. The effective dynamic range is more on the order of 150 dB, quite a big difference from 1500 dB.