Category Archives: Education

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Answers to rhuobhe’s question

The following question has been asked under the “how to adjust compressor settings (part 1)” post:

I have a question for you if you don’t mind. I seem to fail at squashing peaks with high ratio/high threshold because the compressors i’ve tried won’t have fast enough attack times so the peaks partially go through and they end up eating my headroom (unless I use a limiter and that feels like cheating). Am I doing something wrong?

Hello Rhuobhe’s, thank you very much for your participation. I don’t mind, I encourage it ! It seem to me that the compressor you’re using is either not set properly or simply not the appropriate one for your application. Let me explain:

  • Like you have said, yes it’s possible that the attack time is not fast enough. I suggest you to read the blogpost about adjusting attack and release time on compressors that is a bit more recent that the one you posted your comment. If you can set the attack time faster on your compressor, is it solving the problem ?
  • If not, it is definitely possible that the compressor you’re using is simply not the good one. There is a subject that I’ve not covered yet on compressor: Peak/RMS detection. Before taking a decision, the compressor analyze the signal. The way the signal is interpreted has a HUGE influence on how the compressor will sound. RMS detection take into account the area under the curve a certain amount of time before  (averaged value) while the peak is simply taking into account the actual position (instantaneous value).  For signal with dangerous dynamic that might cutoff your headroom, peak detection might be the right choice.
  • About that, compressors are often based on RMS detection (smoother response) and limiter on peak detection. In my case, I think the best is to have the choice. Compressor RMS-detection-based will sound good on vocals, but not necessarily on high dynamic content. That can be also the reason why we have the impression sometimes that a cheaper compressor is better that an expensive one for some application.
  • There is nothing bad using “limiter” if it’s not a maximizer or a hardclipper. A lot of compressor, like VOF Density for example, that let you select between LIM or COMP. In that case, Limiting has nothing to do with maximizer. Those limiters often have a ratio of about 10:1, which  is not clipping. Try to avoid the use of maximizer or hard clipping.
  • I think, in your case, the best will be a peak-detection compressor. Set at near-zero attack setting, it will compress.  If you don’t have one, I can program a simple one for you.

I hope this answered to your question. Please, do not hesitate if you have other questions.

Sincerly,

Chris

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Adjusting compressor settings (part 1)

The typical parameters available on a compressor are the following:

  • Threshold;
  • Ratio;
  • Attack;
  • Release;
  • Make up gain.

To simplify things, we can split this in 2 sections: Gain reduction and time constants. You will usually set the threshold-ratio couple before touching the time constants since the latters are the fine tuning part of a compressor. The make-up is a pretty straight forward setting since its simply the volume compensation you can set to recover from gain reduction.

Threshold and Ratio settings:

Threshold and ratio are working together in order to set your gain reduction. Typically lower your threshold will be, lower will be your compression ratio also. Conversely, higher threshold will allow you to push harder the ratio. How you will set those two parameters will depend on what you’re trying to achieve. Few examples :

  • Vocals : You’re trying to make the vocals compete with a bigband… Good luck! You want the average volume to feel “inflated” but also the peak controlled.
  • Master mix: You’re trying to inflate the mix without squashing the peaks.
  • Drum bus: You’re trying to squash the peaks!!

Every situation will promote different settings, of course, but for those situations, this is what I would be tempted to do:.

  • Vocals : Since we have an important amount of gain reduction to achieve I will go with two compressors with different strategies. One that will serve to increase the overall volume to bring up the details, and one squash partially the louder peaks.
  1. Inflation: Low threshold with low ratio (1.5:1) achieving 3db gain reduction;
  2. Brickwalling: high threshold with high ratio (3 or 4:1) achieving 1-2 db gain reduction;
  • Master mix: You’re trying to inflate the mix without squashing the peaks.
  1. Inflation: ridiculously low threshold with ridiculously low ratio (1.2 or 1.3:1) achieving what you need in terms of gain reduction;
  • Drum bus: You’re trying to squash the peaks!!
  1. Peak squashing: high threshold with high ratio (4 or higher:1) achieving what you need in terms of gain reduction.

See you next week for the following !

 

 

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How to make your vocals shine! (Part 1)

The importance of vocals

Except for instrumental music, vocals are the most prominent instrument of a mix. Some engineers say that if you’ve got the vocals right, you’ve got the mix right. Also, the term “song” would be inappropriate if the point wasn’t about “singing”. Interesting fact, the human ear is way more critical in about vocals than any other instrument. The reason is fairly simple, it’s the only instrument that everyone plays everyday. Futhermore, the human has a deeper feeling towards another human rather than any object. That’s the very same reason why they show human faces in product advertisements. Another interesting aspect of vocals is the lyrics. Currently, the vocals is still the only instrument that can put words on a song. This adds an other dimension to a song.

Enough talk, more tricks!

First thing first:

  1. Have a great song
  2. Have great lyrics
  3. Record it right: The performance must be flawless first.
Once you’ve got that, now we can talk about investing time in a proper mix. Every engineer has their own tricks, but this is a very good recipe: the optimal Vocal mixing algorithm.
  1. Cutting filters
  2. Compressor/De-esser
  3. Equalizer
  4. Exciter
  5. Spatial effects (Delays & Reverbs)

1. CUTTING FILTERS

Why ?

The best way to start is by removing unwanted frequencies and resonances. This will help to make the vocal track cut through the mix more easily. The idea here is to cut unwanted frequencies before the compressor and boosting others after. The reason why we are doing the equalization in two steps is simply to clean the signal in order to help the compressor doing it’s job.

How ?

First, start by removing everything under ~100 Hz and above ~20kHz (Of course, the cutting frequencies will depend of the singer, use you judgement). There are good chances you can also use a peak filter to cut around 700-800 Hz by few dB in order to remove nasal resonances. A good free equalizer to do this job would be the 1982art Gloria reviewed early on this very same blog.

1982Art – Gloria

That’s enough for this time. See you soon for the following…

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What is mastering ?

« MASTERING IS THE LAST CREATIVE STEP IN THE AUDIO PRODUCTION PROCESS, THE BRIDGE BETWEEN MIXING AND REPLICATION – YOUR LAST CHANCE TO ENHANCE SOUND OR REPAIR PROBLEMS IN AN ACOUSTICALLY-DESIGNED ROOM. »

- BOB KATZ, THE ART OF MASTERING.

The previous definition is coming from the book “The art of mastering” which I consider to be the bible of the mastering engineer. Bob Katz wrote down things in a way that nor I or any other mastering engineer could have. It is right, clear and inspiring. For whom this definition is still not clear enough, mastering can be seen as a multipurpose process… Here are listed the basic reasons to get your mixes mastered by a professional:

Homogeniety:

For whom this definition is still not clear enough, mastering is the step where we try to make fit different mixes in a whole. What I mean by that is fairly simple: Some mixes has been done tired at 2am, others fresh as a flower at 9am; some of them sound crazy loud and others very soft… Now, the question is : How do we put them together on a same record ?

Standardization:

Another good reason to get your mix mastered is to sound good everywhere. The problem with mixes, is usually that they have been mixed in less than perfect acoustical environment, so by definition, they won’t translate well everywhere else. A mastering studio will have a near-perfection acoustically treated room and very flat monitoring setup in order to make a sound-good-everywhere version of this mix.

Loudness:

You want your mix to be competitive in terms of loudness ? Okay, but don’t do it yourself, because it is the best way to ruin in 10 sec an excellent mix. The mastering engineer will use its talent, knowledge and experience to make sure that your songs don’t suffer too much from gain reduction undesirable effects. Moreover, mastering engineers use high end gear that helps to conserve the integrity of the master.

 

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What is mixing ? (part 3)

The third part of this subject is based on stereo. Historically, the stereo recording has been invented in the 40s and I’ve been relatively rapidly applied to the music in the 50s. We probably all remember crazy recordings from the beatles (or whoever else of that time) in which the vocals are on a side and the rest of the band is on the other. Without falling into those extremistic approach, it is important to find an appropriate stereo balance that fits the song.

MONO VS STEREO

First, it is important to understand that it is not everything that has to be stereo wide. If stereo is atmospheric, don’t forget that mono is punchy. If you listen to hip hop/rap records, you will notice that most of the record is mono. It is simply because they want it to punch to its maximum. Something too wide will usually sound too soft or not enough focused. That’s why it is important to find a balance between those two extremes.

MONO LOWS and WIDE HIGHS LAW

Well, it is not a law. Let’s say that it is a very strong tendancy that consists to “mono” (yes, “to mono” as a verb!) the low frequency and wide the high frequencies. The way you make the transition between, if linearly or exponentially, is a question of taste, but that’s a good start. Let’s say that human hears like high frequencies to be wide spread and bass to be focused and loud. For the rest, it is yours to experiment and decide what fit most your music genre.

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What is mixing ? (part 2)

audio-compression

As mentioned in the previous topic about “What is mixing ? (part 1)”, we defined the mix as a three dimensional world :

  1. Frequency
  2. Dynamic
  3. Stereo

Of course, like in the real world, we can also take into account the time as the fourth dimension, which is absolutely right. But for now, let us focus mainly on the three first ones. Since the frequency dimension has already been covered in the previous section, let us now move on to the dynamic aspect of mixing.

For some of us, in mastering, dynamic is everything… But from a mixing perspective, what does that mean ? Well, it is fairly simple: Some instruments are more dense than others, so they need to be compressed in order to be “competitive” in the mix. Some people (a lot actually) just compress everything to the maximum in the hope that it will sound crazy loud. Well, if it sounds loud, don’t expect me to believe that it sounds right, or either close to be good.

Honestly, if you want it to sound loud, ask your mastering engineer. This blogpost will encourage you to focus on relative dynamic rather that absolute dynamic (or loudness). What I mean by that is that you should make sure that the dynamic between your instruments is making sense, no matter what the dynamic of the whole song is.

That said, as a rule of thumb, start by simply compressing elements that are not dense enough to compete with others. A convenient example of that is vocals compared to brass. The compressor has not been invented to kill the dynamic, but simply to blend the instruments together. Keep that in mind and your mixes will sound better, I promise.

 

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Towards a deep understanding of the mastering process (part 2)

Second step: Benchmark measurements methods
Once we identified our key parameters, the question is now : how to measure it ? Otherwise, it’s hard to build a reference and we fall into the subjectivity. At this point, some mastering engineers might disagree and that’s okay. The objective here is simply to propose a different approach, a new perspective. Use it or not but, in both case, consider it. That said, let’s look at the tools we could use for our experiment:
  • Tonal balance can be measured via spectrum analysis
  • Perceived loudness can be evaluated by RMS measurement
  • Stereo can be measured with a vectorscope
What’s missing ? A tool to measure the harmonic content of a mix. We all know what is the problem with exciters. The more you turn the button, better it is… until it sucks ! It is a key parameter that is still based on subjectivity only. For an experienced engineer, it might not be a problem to adjust the “right” amount of harmonic content but, it’s not the case for every newbie home-studio owner that work in an less-than-perfect listening environment.
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Third step: Define a standard range of values by reverse engineering
I really like this part which consists to analyze the key parameters of my favourite best-sounding records. I find it exciting, it’s like finding dinosaur bones. Let’s take the 10 best sounding albums of your musical genre and analyze them, both subjectively and objectively. How does it sound ? What do I like in these records ? Only in terms of sonic perspective, what’s different from other genre ? How the dynamic sounds like ? Does it sound bright, muddy, airy, warm or neutral ? Then:
  • Capture the tonal balance with a spectrum analyzer, then compare each of them with pink, brown and white noise
  • Measure the RMS throughout the song
  • Take a look at the vectorscope; how the mix behave in terms of stereo imaging ?
  • Try to print in your mind the degree of harmonic content.
Especially, if you’re testing similar sounding record, you will recognize patterns very quickly. Maybe only 3 records will be enough give you a very precise idea of how it should sound. More specifically:
  • Tonal balance: Is it closer to pink noise, brown noise or white noise ?
  • RMS: What is the max and min value. Is the range narrow ? Is the average making sense for your needs ?
  • Stereo: Does most records behave the same way ? Do you have a good idea of how it should look and sound like ?
  • Harmonic content: Are you going to make it shinny or raw ?
Personnally, I learned from this experiment that I like tonal balances that are between the brown and the pink noise, RMS values between -10db and -12db, a medium stereo spread with high harmonic content. This is a very very very powerful statement!
See you for the following next week !