This guide shows you how to make a guitar produce a convincing bass layer, without changing how you play the rest of the instrument.

The basic idea is simple:

  • You isolate one or two strings with a Submarine pickup (or a SubPro).

  • You send only that isolated string signal into an octave-down pedal.

  • You keep your normal guitar pickups doing their usual job for the main guitar sound.

That way, the low string behaves like a bass guitar, while the rest of your guitar still sounds like a guitar.

Before you start, pick the “bass strings”

Most people start with just the low E string. It is the easiest to control and it keeps the octave pedal tracking cleanly. Once that feels solid, you can add the A string for more weight.

If you are playing in a band, using only one string as the bass layer is often more usable than trying to turn the whole instrument into bass.

What you need

There are two ways to do this, depending on which pickup you are using.

Option A - Submarine (2-string pickup)

Use this if you want the fastest setup and you only need one or two strings isolated.

You need:

  • Submarine pickup

  • Octave-down pedal

  • Somewhere for the bass layer to go: a bass amp, DI to the PA, or an input on your audio interface

  • A normal 1/4" guitar cable from the octave pedal to wherever the bass layer is going

You can also keep your normal guitar pickups going to your guitar amp as usual. That gives you “guitar + bass” at the same time.

Option B - SubPro (best for live routing)

Use this if you want the easiest live control, or if you want to choose strings more flexibly.

You need:

  • SubPro pickup

  • Octave-down pedal

  • Two inputs on your rig if you want to keep channels separate (two amps, two DI channels, or two interface inputs)

  • The SubPro adaptor cable and Y-split cable, so you can break the SubPro output into two normal 1/4" jacks

If the cabling part is confusing, do not worry - the next section walks you through it.

Quick Cabling Explanation

The SubPro sends Channel 1 and Channel 2 down a single small stereo cable (3.5 mm TRS). For this example we only need channel one so a regular guitar cable can be plugged into the adaptor cable.

If perhaps you wanted each bass string on it's own channel or the option of adding the D string in occatsionally you would “break it out” into two regular 1/4" mono cables.

The chain looks like this:


SubPro -> adaptor cable -> Y-split cable 2 x normal mono guitar jacks -> the rest of your rig

Here is what each part is doing:

  • The SubPro output is stereo on a 3.5 mm jack (that is how both channels travel together).

  • The adaptor converts that small stereo jack to a 1/4" stereo jack.

  • The Y-split converts that 1/4" stereo jack into two separate mono jacks.

  • From there on, you treat each output like a normal guitar output.

A good habit: once you have the two mono cables coming off the Y-split, label them CH1 and CH2. It will save you time every single time you set up.

Signal flow (what goes where)

There are two common ways to run this.

Recommended live setup (clean and stable)

This is the easiest to understand and the most reliable on stage:


Normal guitar pickups -> guitar amp (your regular rhythm tone)

Sub output (bass string) -> octave down -> bass amp or DI (your bass layer)


Why this works well:

  • Your guitar amp stays sounding like a guitar.

  • Your bass layer can be EQ’d and mixed like a bass instrument.

  • If something goes wrong with the octave chain, your main guitar sound is unaffected.

One system setup (still works, just more careful)

If you only want one amp or one interface destination, you can blend the two signals together using a mixer, interface, or a line selector:

Sub output (bass string) -> octave down -> mixer/interface

Normal pickups -> mixer/interface

Blend there.

This is fine, but the “two destination” setup is usually clearer and easier to control.

Steps (SubPro)

This is the most common way people do it, because the per-string switches make it easy to choose exactly what happens.

  1. Choose your bass string(s).
    Start with low E only. It is the easiest to keep clean and it will make your octave pedal happiest.

  2. Decide what Channel 1 is going to be.
    For this guide, treat Channel 1 as your “bass output.” That keeps your thinking simple.

  3. Set the SubPro switches.

  • Set the low E string switch to Channel 1.

  • If you also want A, set A to Channel 1 as well.

  • Set all other strings to Off (the middle position).

This is the part most people skip at first: turning the other strings off is what makes the bass layer feel like a separate instrument, instead of a blurry low-end smear.

  1. Plug in the cabling breakout.
    SubPro -> adaptor -> Y-split -> two mono cables.

At this point you have two regular 1/4" outputs. Use the one you have labelled CH1.

  1. Patch the bass chain.

    CH1 -> octave pedal -> bass amp or DI or interface input.


  2. Keep your main guitar sound normal.
    Your normal pickups go to your guitar amp as usual. Set your rhythm tone exactly how you like it.

  3. Bring the bass layer up slowly.
    A bass layer is most convincing when it is felt more than heard. Start quiet, then increase until it supports the groove. If it sounds huge solo but messy with drums, it is too loud.

Small practical note: for this trick, fewer strings going to the octave chain is almost always better. One or two strings is the sweet spot.

Steps (Submarine, 2-string pickup)

Use this if you want a simple setup and you only need one or two strings isolated.

  1. Place the Submarine under the string(s) you want to become bass.
    Most players place it under the low E, or low E and A.

  2. Set the pickup height.
    You are aiming for a strong, clean signal. If the octave pedal is glitching, the first thing to try is moving the pickup slightly closer to the string. If it is too loud or “clacky,” move it slightly further away.

  3. Patch the bass chain.


    Submarine output -> octave pedal -> bass amp/DI/interface input.

  4. Keep your normal guitar pickups as your main tone.
    Normal pickups -> guitar amp.

  5. Balance the blend.
    As with the SubPro method, keep the bass layer quieter than you think, then add only what the song needs.

Cabling (SubPro 2-channel) - detail version

If you want the explicit shopping list and the exact order:

You need:

  • 1x SubPro adaptor cable (3.5 mm TRS male -> 1/4" TRS female)

  • 1x Y-split cable (1/4" TRS male -> 2 x 1/4" TS male)

  • 2x normal mono guitar cables (1/4" TS)

Steps:

  1. Plug the adaptor cable into either SubPro minijack.

  2. Plug the Y-split into the adaptor.

  3. Plug two normal mono guitar cables into the two ends of the Y-split.

  4. Those two cables are now Channel 1 and Channel 2.

Common mistakes:

  • Using a normal mono guitar cable straight out of the SubPro. That will not give you both channels separately.

  • Using a headphone splitter. You need a TRS-to-dual-TS insert cable, not a headphone accessory.

  • Splitting later in the chain when what you really wanted was two independent channels from the start.

Starting settings

Octave pedal starting point

Octave-down pedals track best when they receive a clean, strong note with controlled high end.

Start here:

  • Set the pedal’s mix mostly wet so the bass layer is clear.

  • If your pedal has a tone control, set it slightly darker than your guitar tone.

  • If the pedal has a tracking mode, choose the tightest/cleanest option rather than the biggest sound.

Bass layer in a mix

A bass guitar usually has less high-frequency content than a guitar. If your bass layer feels fizzy or distracting, roll off highs on that chain. Also, do not be afraid to keep the bass layer quiet. You will still feel it.

Troubleshooting

The octave sounds glitchy or warbly

This usually means the octave pedal is not getting a stable note.
Try this in order:

  1. Move the Sub pickup a little closer to the string to increase signal strength.

  2. Reduce treble going into the octave pedal (tone knob, EQ, or a gentle low-pass).

  3. Add light compression before the octave pedal if you have it.

The bass layer triggers when you do not want it

This is almost always a muting problem rather than a gear problem.

  • Start by being stricter with your right-hand muting on the bass string.

  • If you need a guaranteed solution live, put the bass chain through a mute or line selector so you can kill it instantly between parts.

The bass is too quiet

  • Confirm you are actually splitting the SubPro output correctly (adaptor -> Y-split -> two mono cables).

  • Make sure you are only sending one or two strings to the bass channel, not four or five.

  • Check the first device after the split. If it is expecting line level or has a low input gain, you may need to raise gain there.

FAQ

Can I keep my normal pickup tone and add sub-bass on top?

Yes. That is the whole point of this setup. Your normal pickups are the guitar. The Sub pickup feeds the octave chain as a separate bass layer.

Do I need two amps?

No. Two destinations is cleanest live, but you can do it with a mixer, interface, or PA with two inputs.

Which string should I start with?

Start with low E only. Once that works reliably, add A.

Should I send more than two strings to the octave pedal?

Usually no. That being said, three is very much possible but requires some rather dextrous and precise playing.

Written by Submarine