Why And How To Keep Low End In Mono in FL Studio

In this tutorial, I will give you few ideas and thoughts why you should make sure that the low end of your EDM track stays mono and how to do that in FL Studio.

First, why is it important to make sure that the lower frequencies of your mix are in mono, especially if it’s aimed for clubs?

The “low end” is the FUNDAMENTAL in electronic dance music. The low end holds the energy of your whole track so it needs to be as solid (and punchy) as possible.

What could possibly make the low end sound inconsistent and not so punchy in a club sound system?

Some stereo widening effects such as chorus, haas effect tricks, etc. Even though they are cool and they have their place when applied to UPPER FREQUENCIES, they can be BAD for low frequencies.

Why?

The thing is, if the stereo widening effect sets the phase of the audio between the left and right channel out of sync (which they usually do), and you don’t have an option to control the frequency range where it will be applied, your low end may suffer phase cancellation issues when those channels are mixed together.

Many club PA’s sum low frequencies to mono and if your low-end material is having a left and right channel phase mismatch, bass levels may sound inconsistent and it’ll partly loose the focus. And that’s bad.

(And also, maybe not so relevant these days, but IF your song is going to be pressed on to vinyl, the low end needs to be mono anyway.

By keeping the bass in mono, you will ensure, that your track retains its energy and hit hard in the dance floor.

And even if the club is having a full stereo system, the installation, alignment and how people are positioned on the dancefloor, varies. Many people are standing so that they hear only one of the speakers. In fact, only small amount of people are in the middle of the floor to hear the music in full stereo.

That is why you need to make sure that the low end sounds consistent whether it’s listened in stereo (in ideal position) or summed to mono and/or listened to only one speaker.

So keeping the bass in mono already from the beginning of the production is indeed a good idea!

Ok. Here are a couple of practical ideas you can do to keep the bass section of your track in mono.

Stereo Analysis Tool And Mono Tricks

For starters, you might want to load some stereo analysis tool to the Master channel of your DAW to keep an eye how the audio signal is spread in the stereo field. If you don’t have one, check out Stereo Tool by Flux. It’s an awesome free stereo imaging and analysis tool and that’s what I’m using in this tutorial.

Reading the analyzer is pretty self-explanatory: the wider the stereo spread of the audio signal, the wider that yellow/orange visual stuff in that vertical axis:

And vice versa: if the left and right signals are identical (a monoaural signal) the result is a straight line:

Ok. I have loaded a kick drum as an example and routed it to one of the Mixer insert tracks.

As you can see (and hear), the kick is slightly spread in the stereo field – most likely in the higher frequency area so it’s not completely mono:

Now, your DAW usually has some inbuilt option or a plugin to set audio to mono.

In FL Studio, there’s a Stereo Separation knob in the Mixer which you can use to merge left and right channels.

Turn it all the way to the right and it will sum the left and right channels to mono:

As you can see in the Stereo Tool, the kick is now mono:

So this is a quick way to “monoize” any audio.

However, what if you want to retain the stereo spread of those upper frequencies, but still want to make sure that the low end stays mono?

You can use i.e an equalizer which has a mid/side processing option, such as Fabfilter Pro Q. With mid/side EQ, you can use a low cut filter to filter out all the stereo information from the low-frequency area.

In FL Studio, you can use Maximus for something similar and here’s how:

Load Maximus to same Mixer insert track where your kick is and turn OFF the compression for all the Bands (including the Master) as we are not going to use Maximus for compression here. We are using it just for controlling the stereo width of different frequency ranges:

Click the Low Band and dial the Stereo Separation -knob to 100% merged. This’ll sum stereo data to mono only in the low-frequency area defined in the low-frequency band settings.

Also, as a side-note: set the Look-ahead delay (LMH Del) to zero milliseconds to avoid latency delay appearing to the Maximus output. The look-ahead delay control has it’s used if you use Maximus for compression and/or limiting, but in this case, it’s not needed.

Switch on the Bands display to see what kind of frequency range the Low Band covers and use the Low Band Frequency knob to set the Low band frequency cutoff value. Set it to around 90 or 80 Hz. This’ll mono everything starting from that frequency value and below, but leaves the stereo information above that intact:

Let’s move on…

Making Bass Presets Mono

But what about those bass sound presets included in your favorite synth plugin? There are tons of ready-made presets and you can’t be 100% sure whether the low end works in mono.

(I’m using Spire and one of its factory presets “BA Drill Bass” as an example here):

So how to make sure the low end stays in mono?

You can use the same process as with the kick: mid/side EQ or Maximus.

I’m using Maximus here so I’m just going to drop it to the same Mixer insert track where Spire is routed and use the same settings as with the kick: I turn off the compression for all the bands, merge the Low band to mono and set the Low band frequency cutoff value to around 80 Hz. This leaves the stereo spread in the upper frequencies intact.

Now watch the stereo analysis tool as I isolate the low-frequency band (isolating can be done by simply muting the Mid and High bands):

Voila, it’s in mono!

But did this particular preset actually require “monoizing” the low frequencies? Did it contain a stereo information? And how to check it?

You can check it with Maximus: while the low-frequency band is still isolated, set it’s Stereo Separation knob to default and watch the stereo analysis tool:

As you can see, the low frequency range of this bass preset does contain a stereo information. But there’s not much of it and at least to my ears, it seems to sound alright when summed to mono. So this particular sound could’ve worked perfectly well in a mono sound system as is.

However, checking how the lower frequencies sound in mono already at this stage of production, keeps you safe from nasty surprises when the track is going to be played on a dancefloor.

In worst case scenario, some bass presets may contain so much stereo manipulation that when you mono the low frequencies, complete phase cancellation happens from time to time. If that’s the case, then simply by merging the left and right channel isn’t going to fix that. It just makes the phase issue apparent in an early production stage.

Even though the stereo analysis tool helps you to see the stereo width visually, you need to let your ears to be the final judge: when you mono the low-frequency range, and listen to it in isolation, does it sound weak from time to time? Is there an inconsistency in its volume level?

If it does, you might want to check out how the bass sound patch is build. Depending on the synth plugin you’re using, check the effects or special features that affect to the stereo width, such as chorus, some special stereo widening parameters, etc.

If there isn’t an option to set a specific frequency range where the effect will be applied, try decreasing the stereo widening effects until the low frequencies sound consistent in mono.

So with that said – and if you’re wondering why I’m not advising to just pass the whole mix through mid/side EQ, Maximus or some other tools that can make the low frequencies to mono: It’s one way to do it for sure, but by making sure that fundamental low frequency sounds works in mono already in the early production stage, makes it possible to spot possible problematic sounds and frequencies and fix them right away, which – in some cases – would be very hard or impossible to fix just by processing your whole mix with low frequency mono summing tools.

EDIT: Also, in some cases, you may want to mono slightly different frequency areas separately for kick and bass, which isn’t possible if you use the mono tool just in Master channel.

However, one way to deal with mono compatibility is to use e.g Maximus in the Master as a sort of ‘analyzer’ to keep checking how the low frequencies sound while you’re producing and if you spot a wonky bass sound then go and deal with it individually.

Bulletproof Way For Mono Bass

If you want to be 100% sure that the low frequencies of your favorite bass preset is mono compatible, but you still want to retain a stereo depth it has in the upper frequencies, try this:

Cut all the low frequencies off from the bass sound and layer a pure sinewave bass underneath it.

In FL Studio you can do it easily by using 3xOsc and Layer channel. Here’s a step-by-step process:

Assign the plugin that contains your favorite bass sound preset to an empty Mixer track and use i.e Fruity Parametric EQ 2 and high pass filter to roll off everything below – let’s say – 100 Hz:

Next, load 3xOsc and make sure you have a sine wave selected as oscillator type for Oscillator 1. Disable Oscillators 2 and 3 by setting their Mix level to 0%. Tune down the Oscillator 1 by two octaves by setting it’s Coarse pitch to -24 semitones.

Next, go to the Instrument settings and set a Root Key using the Preview keyboard. This is where you define which key plays the current pitch of the Channel.

This is also useful feature when you want to play i.e low pitch notes with those middle keys of your MIDI keyboard.

The default root key is C5 (C5 is the middle C – MIDI note number 60 – in FL Studio).

So in this example, when you hit a key of C5, the 3xOsc gives you a lower C as we tuned down the Oscillator 1 by two octaves from it’s default pitch. Measured in hertz, that’s 130.81.

Now, 130.81 Hz is a bit too high for a sub bass when played from middle C, so you might want to set the Root Key so that when you hit C5, you’ll actually get a low C (65.41 Hz).

In order to change the Root Key setting, simply right-click a note to in the Preview keyboard. Set it to C6. That blue note shows the root key of the channel. Setting the root key higher will cause a given key to sound lower in pitch. So now, when you hit a key of C5, you’ll hear a low C (65.41 Hz) which is good for sub bass.

Why is it important to set the Root Key when layering sub bass with another sound if you do use the Layer channel method?

To make those two sounds sound alright in relation to each other.

The thing is, if you use the Layer channel method (and perhaps a MIDI keyboard to play the notes), remember that you use the same channel and MIDI notes to play two different sounds – two different synths which might be tuned differently.

That is why you want to make sure that 3xOsc sub bass goes low enough in relation to your bass preset sound.

You don’t want to leave it too high, but on the other hand, not to make it go too LOW either.

In most cases, setting the Root Key to C6 works just fine as many basses presets has been tuned so that middle C gives you that 65.41 Hz.

However, if you’re not going to use a Layer channel method, just leave the Root Key as is as you can draw the notes manually to the Piano Roll and go as low and high as you want independently with both sounds.

As a side note, check out StereoSavage by PluginBoutique. It’s a quite accurate VST stereo tuner. It’s quite helpful for all kind of tuning tasks if you feel you can’t fully trust your ears.

Ok.

Next, load a Layer Channel and set those two instrument channels as Children by selecting them with the Channel selector and clicking “Set Children” under that “Layering” dialog:

That’s about it. Now you can use the Layer channel to play both instruments and you have a 100% mono low frequency bass.

The end 🙂

Watch the video version of this tutorial below: