Sub bass tip 3: how loud should the sub be in your song?

Alright, time for sub bass tip number three!

I'm not always big into teaching numbers when it comes to mixing and mastering, but there are scenarios where they can be massively helpful. This is especially useful if you don't have a system that offers great sub bass reproduction.

One question I get often is "How loud should the subs be in my mix/master?" and I'm here to address this today.
Every now and then I get premasters where the sub is sometimes way too loud (if I mix the song, I can handle it myself better), so I do see this isn't super basic stuff for everyone. While I sure enough can pinch the sub region in mastering when needed, having a sub that's not massively too loud will be helpful in nailing that perfect master.
Let me help you get the sub loudness roughly right! It's easy once you get into it.

First, the only master analyzer I've used for so many years now is the free Voxengo SPAN. It's great, and it's all I use when it comes to this specific matter.
The settings above^ are what I use, and the Slope setting that's in red above is critical to my tip, should you follow it; it has an effect on how the angle of the slope.
The tip I'm giving here mostly relates to bassy music such as house, tech house, drum and bass, trap, etc., so this most definitely would not apply to rock, old skool hip hop etc. where you don't have a sub bass.
Also, this has to do with songs that are limited to comparable loudness (just run your song into a master limiter to achieve that loudness – for the purposes of checking the sub level, it doesn't have to work out super clean: we only need to get that song level up temporarily).

The way SPAN works in checking for frequencies and their loudness is this: when you place a cursor anywhere, you see the frequency of where your cursor is (top left) and its loudness by some SPAN proprietary loudness number (top right).
First, this allows you to see where your sub is hitting (see my previous post, sub bass tip number 2) and its loudness.
I've analyzed a whopping amount of bass music masters over the years and (here comes the main tip!) noticed that there's definitely what I could call a "ballpark loudness" for sub bass.
What is it then? It's roughly where you reach -30 number on SPAN's loudness for that frequency.
For example, in the pic above, the cursor (see the crosshair – cursor isn't showing due to MacOS screen grab), the sub is peaking around 48 Hz (so it's in a good place) and its loudness is slightly below -30 (you see the crosshair is slightly above where it's actually peaking).
So in a nutshell: when analyzing your master (when it's limited loud enough), put your cursor at that -30 spot (so you'll get that -30 at top right) and aim at your sub bass hitting that loudness, and I guarantee it's in the ballpark.

I could post so many pics of good bass music masters thru SPAN, but their sub placement looks roughly like this in all good masters: the sub is around 45-60 Hz, ideally, and its loudness is that -30 by SPAN's loudness metering (top right) when the master is pushed to decent loudness.
Also, don't just take my word for it: I encourage you to check some of your fave bass music masters this way for their sub level, and you should find this to be true.

Well, it's as simple as that.

Some relevant considerations:

1) Where is that sub bass coming from?
It can of course be a combo from your kick and bass, but your bassline at least should be hitting that spot. In general, for example house / tech house kicks prob hit slightly lower than for example D&B does; D&B usually has its kicks a bit higher and they're not necessarily as whoompy as house kicks are – but there are exceptions in both genres, of course, so I don't want to try and generalize this too much!
DNB, I feel, leaves a little more room for sub bass, while house may have subbier kicks and slightly less subby basslines.
But to have things in the ballpark, limit your song to reference loudness, have the sub loudness right, and then chew on how the sub may be divided between your kick and bass – you may set it to taste.
(If you want to have another numerical guideline that can help you: for ideal separation, have your kick peak at least 20 Hz higher than your sub bass. Even more is better. All this depends on the kick. You can of course have a really subby kick, but just make sure it's not playing at the same time with the sub OR have a bassy tail (keep it short!!)

2) Does this apply to a non-limited mix?
Nope! This is only applicable when your song is playing at a level that's comparable to the loudness of commercial/released masters. Even if you're not super interested in mastering, you can do this sub level check when you just slam your song into a limiter/maximizer (or two if needed) so that its perceived level (measured by your ears) matches that of your reference song. Now that is when you can check the level of the sub as described in this post.
(NOTE: you can of course gain your reference song DOWN and then do the comparison (it's just, then don't go for the bass loudness number I gave you: check that of the reference you gained down).
Btw, if the song is distorting a lot at that level, it's likely that is has too much sub and/or clashing between kick/bassline subs and low-mids. You may find out this way that your song may have too much sub (or not enough, especially if you find it's super easy to crank your song louder than your nice, bassy refs).
I'll also add that limiters offered by DAWs are mostly really bad for master limiting, but they're still OK for checking the sub level...so if it completely smashes your song, yeah, that's what DAW limiters do, but let's just stick to checking that sub level for now, and your DAW limiter is prob OK for that.

3) Aren't some genres less loud than some others, and do they still have the same amount of sub?
Yes. For example, deep house is less loud than, say, more EDM-type house. They still might have a somewhat similar amount of sub when compared – it's just the more dynamic genres usually have relatively more sub bass (this is why they kind of hit harder in the club). They have more room for it. The mega-loud songs have relatively less sub (their sub hits roughly the same loudness as less loud bassy tunes, but the bass isn't relatively as loud in the mix).

4) Sometimes I make my sub hit that spot and it feels too much – why?
If you have lots of harmonics in your bass in 120–300 Hz range, sometimes it feels you may want to have a bit less sub, I feel. Also, when you have really subby bass with no harmonics and your kick hits nice and high, it's often nice to make that sub bass a bit louder, as there's more room for it.

Well, hope this helps!
Remember that every song is individual, and all this info is ballpark info, but still, it should help you to get the bass roughly right.

Coming up next:
• the most common mix issues
• the things I do to achieve perfect kickdrums
…till then!