This is the final post in this Mixing Bass Series.
In part 1 of this series, I talked about common bass problems. In part 2, I gave you some tips for EQ-ing bass. Today we need to take a look at how to use compressors and limiters to properly handle bass.
I’m writing this with the assumption that we all have a good basic understanding of what compression does. I want to look specifically at how we can utilize compression to make our bass parts better.
Does the bass need dynamics?
This is a question worth asking. Do we need the bass to have a huge volume range? Or do we want to tighten down and make it very one-dimensional, with every note being the same volume?
If you’ve hung around HSC for very long, you probably think I’m going to pick the first option. But I actually think that the less dynamic range the bass has the better.
When mixing a pop/rock song, where you’ve got the typical bass, drums, guitars, etc., there’s one thing you want to be constant – your bass tone. If each note the bass player plays is at a dramatically different level than the next, you’ll end up with sections of the song where the bass just seems to disappear. In other sections, though, it will be overwhelmingly loud.
What to do?! Compression to the rescue.
Let me just say that this doesn’t apply to every bass part ever recorded. If you’re doing a jazz tune, you probably don’t want to slam the upright bass with a ton of compression. (Heck, you’re probably not gonna use much compression at all on a jazz track.)
However, if you’re mixing a pop/rock song (or if you think you’ll ever mix one in your life), read on.
The Purpose of Compression
For most instruments, I use compression to change the tone. I’ll use it to make a vocal more “up-front,” or I’ll use it to bring up the sound of the room on drum overheads.
With bass, though, it’s different. While compression does have its tonal effects on bass (like bringing out pick noise and increasing sustain), I primarily use compression to even out all the notes.
Ideally, every bass note in the song will sound exactly the same, perfect consistency from note to note. That’s one of the things we look for in a bass player, right? They play consistently.
We want our bass part to be heard and felt on every beat of the song. Therefore, we need to employ compression and limiting to make the notes as consistent as possible.
How I Set Up Compression/Limiting on Bass
Rather than go on and on writing about the various implications of using compressors and limiters on bass, let me walk you through how I set things up for my sessions.
After EQ-ing the bass, I’ll add a compressor. (I EQ the bass first because I want to get rid of any unwanted frequencies. A compressor will make these frequencies louder, so you want them to be gone before you compress.)
Here’s a screenshot of one compressor setting for a mix:
There’s not a ton of compression going on here. I try to use a longer attack time, so the transients still come through. The purpose of the compressor in this example is to bring up the overall volume of the bass, particularly the sustained notes.
After compressing, I’ll put a limiter on the track. The limiters job in this instance is to completely squash the bass, preventing it from getting any louder.
You’ll notice that the threshold is about 6 dB below the ceiling. That difference is bring up the overall volume of the bass. The ceiling, though, is preventing that volume from going past -7.6 dB.
This makes every bass note almost exactly the same volume. Bringing that output ceiling down allows me to control the output volume of the bass. Bringing the threshold down throws everything that comes through the limiter up to the ceiling, where it is prevented from getting any louder.
If you’ve never used a limiter before, this can be a bit confusing. However, once you understand what’s going on here, you’ll realize that a limiter can be a useful tool for more than just squashing your entire mix.
I don’t use this technique on every song I mix, but hopefully I’ve given you something to think about and experiment with next time you’re in the studio.
What compression/limiting tips do you have? Leave a comment!
[Photo by peff]
Just a minor bass-specific thing to be wary of at this stage, is if, and where, uneven ’spots’ exist at different points on the neck of the instrument; most basses will not be completely even in volume across all notes on the neck, some frets can be a little ‘boomy’- take some time to listen for these. If any of these are evident on the particular instrument, it will usually sound better if you can cut those little giblets of frequency buildup before you even consider dynamics processing. Reason being; these hotspots are often a huge contributor to the ‘unevenness’ of a bass track, and ‘DESTROYING (lol)’ them can reduce the amount by which you need to crush the track.
“In either case, deciding in what order to use the EQ and compression is
”
going to take some careful listening each time
Precisely!!
Thanks for the replies everyone, especially Sparqee. I've been mixing, as a hobby, for less than a year and I still find compression to be a bit of a 'black art' some of the time. I have to say that Joe's 'Intro to Compression' video has helped me enormously and discussions like this can only be more helpful still.
I think I've got to the stage where I agree that, in general, cutting is better than boosting but, as Sparqee has pointed out, sometimes a boost is what is needed (eg bringing out the 'click' on the kick drum or, as Joe mentioned in part 2 of this series, bringing out the pick / finger noise on the bass guitar). In either case, deciding in what order to use the EQ and compression is going to take some careful listening each time
Noob here. Can you clarify what you mean by “higher headroom”, its relation to the bit capacity of your DAW, and how that helps prevent clipping at a later stage?
If this is this just a buffer overflow problem, as I suspect it is, would the problem be ameliorated by a 64-bit system, or would you need a DAW that can operate in 64-bit mode as well?
(Also if you could relate any of this to Logic Studio I'd be grateful, since that's the DAW I use.)
I agree. I approach mixing like creating a statue. You start with a huge block of marble (or 24 audio tracks). You don't ADD more stone to make it look like a man. Instead you carve out big chunks of marble until it looks like a man.
Music recording forums & magazine articles have certainly over simplified the cut vs. boost consideration. Lots of times boosting is the way to go, but I think it's useful to consider the strengths of the cut vs. boost philosophy. Beginner tend to simply boost what they want to hear more of and they quickly end up with a lot of competing tracks. If on the other hand they develop the discipline to listen critically and discern which sounds are competing for the same freq range they can make better informed choices about when and what to cut or boost. The philosophy of cutting over boosting leads you to listen more critically and to pay more attention to the actual problems.
As so often happens the story has become over simplified and the true value of the story has been lost.
Regarding prioritizing cuts over boosts, that practice makes a lot of sense with low headroom mixers (such as what your typical home studio might have… eg: Mackie, A&H, Soundcraft) because, in addition to introducing phase shifting, you're likely to overload the next stage or even the buss (especially if you're boosting across multiple channels) which, in those designs, is often very unmusical.
In a higher headroom environment, such as Protools LE's 48 bit fixed, or most other DAWs 32 bit floating mixers, this isn't nearly as much of an issue, though you still need to pay attention to gain staging. If you clip a succeeding stage, boosting will sound bad, but if you don't it's really not the bugaboo that internet conventional wisdom has made it out to be.
Yes. A common order is: corrective EQ -> compression -> tonal EQ
Hello,
Great post. Up til now I used the following:
Bass in ==> Light EQ (to cut unwanted frequencies) ==> Comp ==> proper EQ
Thanks for the limiter tip. I'll try that asap
Good thought. Thanks for the clarification.
For the sake of noobies that might misunderstand your post; saying that post EQ compression will “effectively nullifying the boost” is a bit misleading (unless you're using a multiband compressor). It is true that a pre-compressions EQ boost will effect the compressor's behavior but a standard single band compressor is still acting upon the entire frequency spectrum of the sound. This can actually be used to your advantage. If you want your compressor to react to a particular part of the sound you can accentuate that with a boost to key your compresssor. Of course to make things more interesting there's also the issue of compressors reacting more strongly to low frequencies but that's another story.
There are fine reason for EQ'ing either before or after compression and in some cases *both* before and after. All depends on what your after.
I generally have a cut and a boost on my bass EQ, so i s'pose that whatever order I do my EQ and compression in, something is going to get slightly compromised
I can see your point, but I typically try to use EQ to do CUTS rather than
boosts, so it makes sense to cut them before compression, so the compressor
doesn't boost the offending frequencies even more.
Thanks for this Joe, especially the part on using the limiter after compression.
I'm not sure I agree with you about the order to put your compression and EQing in the chain. I generally do the compressing first, then do my EQing. My reason for doing this is that putting a compressor after the EQ will then cause any boosts I've applied through EQ to be compressed, effectively nullifying the boost. I can't remember where I first picked up this tip (it could well have been on your site!). However, I can also see the sense in your reason for doing the other way around. I guess I'm just going to have to use the oldest rule in the mixing book – use my ears!