Welcome Friend! This is the first lesson in the Beginners Guide to Audio Engineering series.
In this lesson series we will cover the different tools at our disposal. We’ll work 1 on 1 with each tool and discuss how, when, and why to use them. We’re covering the basics here so I'll be assuming you’ve never used any of these tools before. Though they were introduced in the fundamental lessons, we’ll actually use them in practical manners in this series.
First off, we’re going to start with the Spectrum Analyzer. Though it's not a tool that manipulates the way the audio sounds, it’s an invaluable tool that allows us to see the audible spectrum. Hence the name, Spectrum Analyzer. When working with audio the cleaner we can make the signal, the better off our final product will be. One thing that plays a BIG role in our ability to hear things accurately is actually our room! So no matter how good your monitors are, you’ll inevitably run into a set of frequencies you just can't quite hear in your listening position. This is why the bass gets louder when you stand in the corner of your room vs. where you sit at your desk. (haven’t noticed? Try it out, play a song and move around your room taking note of where the bass is louder vs quieter).
Even if you are using headphones, there may be sub frequencies that your headphones just can't replicate. In any case, having a Frequency/ Spectrum Analyzer can help tremendously!
My personal favorite is actually a FREE tool from Voxengo called SPAN (Link Here). This tool has been my right hand for many years. That being said, it will be the Spectrum Analyzer I will 1. Recommend, and 2. Use as a reference in the remainder of this lesson as well as many future lessons. I will also show you how to set it up so that in the future lessons whenever I pull out SPAN, your signal will look just like mine if you want to follow along. Straight out of the Box SPAN has some odd settings so I recommend adjusting them before analyzing anything.
Without further ado, LET’S DIVE IN
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Understanding the spectrum, phase correlation, frequency analyzers, and other metrics for professional audio monitoring. (Voxengo Span based)
First off, What is a Spectrum Analyzer? In other words and with synonymously interchangeable terminology, it is a frequency analyzer. It allows us to see frequencies in both the audible and inaudible frequency ranges. Thus it covers the whole spectrum of human hearing and then some. Though I’ll be using SPAN as a visual reference, spectrum analyzers pretty much all do the same thing/ look the same. If you’ve seen one analyzer you’ve pretty much seen all of them. Some might have some extra features (SPAN) that others don't and so on.
When I say Spectrum, I’m referring to the entire audible range of human hearing which is 20Hz to 20,000Hz. Analyzer is a visible display of said spectrum, thus allowing us to see what's going on with our eyes whilst also hearing it.
It’s important to remember that what we hear is more important than what we see. This tool is just a helper, not an oracle that has all the answers. You can destroy music if you mix with your eyes. In fact it's better to make all your choices with your eyes closed in order to prevent. That being said, let’s dive into the different parts of a spectrum analyzer and in our case, SPAN.
The Spectrum
The Spectrum view allows us to see the different frequencies in Green. (Note: My SPAN skin is Blue, though it normally comes in a grey color. The green is the same though!) In the image there is a full song being played. One thing you might notice is the odd shape of the grid. Spectrum analyzers are normally structured bands called Decades.
Starting at 0Hz we move to 100Hz. This is our first Decade. If we multiply 100 x 10 we get 1,000Hz which is displayed in the center decade from 100-1,000Hz. The next decade would be 1,000 x 10. This brings us to 10,000Hz which is shown to be our 3rd decade 1,000-10,000! This has to do with harmonics and maths which I've covered in the Audio physics lesson on harmonics and fundamental frequencies . While these decades can be broken down into smaller sections, we’ll leave it here for now.
The Range
Similar to the above section, the bottom of the spectrum shows us a range of frequencies which I have set to 20-20,000Hz. As previously mentioned SPAN can be adjusted to view above and below the audible spectrum. From 0Hz all the way up to 96,000Hz! But remember, humans can only hear from 20-20,000Hz so really it's overkill for our purposes. Again you can also see that they are spaced according to decades.
The lowest frequency is always on the left and the highest frequency is always on the right.
Bass is left and highs are right. Always.
Output Level
The output level is in dBFS (dB Full Scale). So it will match the dB range of your typical DAW. (almost all computer tools will use dBFS unless specified otherwise) If you want to know more about the dB check out this lesson (Here). This is simply so we know the output level of our signal. This meter is essentially an Input and an Output meter as there is no way to change the gain level in SPAN as it is passively looking/ listening to our signal. It doesn't apply any effect to the audio. Spectrum Analyzers display what they are given.
Extra Metering
Span has some amazing feature that we’ll cover in later lessons when we get close to mastering our songs like RMS, Crest Factor, and the Stereo Correlation Meter (super duper awesomeness) which are outside of the scope of this lesson but feel free to research on your own if you feel compelled to! We’ll cover these when they are more relevant. No need to get too lost in the sauce just yet.
There are a lot of ways to alter the way SPAN looks and behaves. While each setting can have its own lesson, we’ll cover the basics on how to set it up to best suit your needs.
Located in the top right corner of the spectrum view, there is a gear icon that will allow you to access the settings page.
The settings below are my preferred settings which you can copy exactly i you so choose, but recommend following the example in the video in order to find your own. Though, i’m sure you’re bound to end up with these settings for reasons you’ll begin to understand in the later parts of this lesson
Firstly, let's cover Slope. Getting your slope wrong can visually mess you up pretty hard. Why can it mess you up? Check out the photos below. The same signal is being played. The only difference is the slope setting
Low Slope
High Slope
If you don't use your ears you’re mixing wrong.
This is a lesson on why using your eyes can be detrimental to your audio. Your eyes can lie to you. Misconstruing what your ears hear and pushing you to make changes based on what you see. We’ll get to how I arrived at the slope of 4.5 in a minute. For now I want you to understand that what you see isn’t always what you get.
Slope changes the angle at which your signal is sloped, and it's anchored at the 1,000Hz mark. A Lower slope will raise the low end of the spectrum and a higher slope will raise the hgh end of the spectrum. This does not change the gain of the signal, it only changes the way it is visibly represented.
How did I come up with 4.5 being my preferred slope? I watched all my favorite songs play through SPAN (I demo this in the video at the bottom of this lesson). Watching your favorite songs in a spectrum analyzer is a game changer. Because you can then have an understanding of their frequency content and levels. Not only can you listen to your favorite songs in your own environment, you begin to gain an understanding of what your mixes should sound like/ look like on an analyzer in relation to your favorite songs. When I say favorite songs, I don't mean the ones that I made, I mean the professionally mixed and mastered tracks of your favorite artists. Click and drag them into your DAW and simply watch and listen.
I came to the conclusion that 4.5 was the right slope for me because the bass of the track was roughly level to the high end of the track, making it look like a flat line across the top.
You’ll hear me reference ‘the 30 Mark’ on SPAN, it’s easier understood when watched in context of the video below so check it out! I’ll talk about it a lot more often in the context of the actual mixing and mastering processes. It really is a magical mark.
The 30 mark can be found by adjusting your “Range Hi” setting to -25.5 and your “Range Lo” to -91.8. This simply adjusts the vertical grid lines. The manual says the “Range” settings are in relation to the dB level but I couldn't tell you what version of the dB it’s using because it always seemed like an arbitrary scale to me. Regardless, all I’ve cared about since I found it has been the 30 mark.
Freq. Lo: is our lowest frequency on the chart.
Freq. Hi: is our highest frequency on the chart
Soothing: by ¼ Oct allows us to see a general overview of the decades without too much detail and or not enough detail. By all means play around with the settings to find what you like! We’re all different. Often I found if I had too much info I would make more decisions based on how it looked instead of how it sounded, but if I smoothed it out too much it wouldn't give me an accurate reading. ¼ just started to feel right after I played around for a while
Block size: is the depth of information. You can think of a block as a frequency. If we had 20,000 blocks we would have 1 block per frequency. If we had 1 block, we would have 1 block for all 20,000 frequencies resulting in the whole spectrum moving regardless of what frequency played. 8192 blocks is another one of those settings where I just fell into a groove of not too much info but not too little info. It averages the spectrum out well and provides an ‘even enough’ field that doesn't over or underwhelm the visual senses. I’ll say it again, play around with this setting to see what you like.
Type: it the type of meeting, in this case we want RT AVG which stands for Real Time Average
Avg. Time is how quickly the spectrum moves over time. I like this to be fairly short, but not instantaneous. When it moves too fast it doesn't really help anything, if it moves too slow you don't get an accurate representation of what's actually happening. 598 is what my mouse landed on when tweaking the setting and it isn't a dead set number it's just what I ended up on whilst watching the spectrum dance around and what I found visually accurate to what I was hearing.
You’ll notice how much I said “I” in all those descriptions. It’s because they aren't settings founded by Law, but discovered over time, trial and error, and a little bit of method. Play around with the settings and find what works for you. Watch the video to see what I did in order to find my settings.
Saving Your Settings
Once you’ve adjusted SPAN to your liking Press the “Presets” button in the top left corner of the setting page.
Use the (+) button to add a Preset and provide it a name that you’ll remember. Once it is added to the list, select the “Activate” button to activate the settings. You can confirm that your new settings are being used in the top right corner of the spectrum viewer. In this case my preferred settings preset is called “MINE”
This should save the default state of SPAN so for every new session you open your default settings should remain as you last had them. But it's always a good idea to double check!!
A Spectrum Analyzer is a tool that allows you to see what you can't hear. They are helpful in poor monitoring situations and can be a great tool if you switch up your physical environment. It will give you a sense of ground if you move from studio to studio, headphones to speakers. You’ll begin to notice how much your environment can change the way your audio sounds. But your Spectrum Analyzer can be an anchor point that helps ground your decisions when it comes to translation, or how your song sounds on different systems in different environments. We’ll touch on that in the mastering lessons.
Before I end this lesson I want to cover one more thing that may be helpful as we start this journey. We just covered a 3rd party plugin but I never showed you how to install it. As I mention in the fundamentals of computer based audio engineering lessons File management is very important.
Remember the 1_A_Master_Folder? If not here is a brief description and overview
The 1_A_Master_Folder contains EVERYTHING related to your audio work. Whenever you install a new application, plugin, tool, or audio samples. You should install them into their specifically named folder within their classified subfolder within the 1_A_Master_Folder.
In the case of SPAN, you should install it in the “effects & Tools” folder more specifically, you should make a folder inside the Effects & tools folder titled “Voxengo” and inside the Voxengo folder create another folder called “SPAN” so the following file structure should be as follows
1_A_Master_Folder >> 1_A_Master_DAW_Folder >> Effects_&_Tools >> Voxengo >> SPAN
This way you will always know where literally everything is.
Now, when you install SPAN it will ask you where you want to install it. And you can install it into the SPAN folder you just made, and the fresh install of SPAN will live inside the SPAN folder inside the Voxengo folder Inside the tools folder inside the DAW folder inside the 1_A_Master_Folder. tThis will keep you more organized than you ever thought possible
After you’ve finished installing SPAN into your newly created SPAN folder. Head over to your DAW’s preferences. There should be a settings tab for Plugins. This will allow you to select a folder. What folder do you think we choose? That's right, the 1_A_Master_Folder!. Now your DAW will look at this folder for everything you own related to music and audio! Ahhhh, it’s all coming together.
Note that my folder in the image is titled 1A FL Master. Though it's not exactly 1_A_Master_Folder it still contains the 1A and Master within the name. This is before I fully developed the method that I'm teaching here. Though it’s not exact, I DO practice what I preach.
After you have SPAN installed and you’ve selected your 1_A_Master_Folder as the folder your DAW should check for plugins, hit the rescan button.
Once this is completed you can check for your tools in the plugin area where you’ll be pleased to see the Voxengo folder that contains SPAN!
From Here on out, you can install plugins in this very way, and they will show up in exactly the same place though within their own respective folders!
Note: Some plugins come with a VST2 and a VST3 version and sometimes you can install both of them in the same folder. If this is the case make one more folder specifically for the VST3 version but make sure it’s still within the right folder so you don't lose it.
This concludes the first lesson in the Beginners Guide to Audio Engineering lesson series!