SP404 MK2 Bus FX Explained: How to Make the Most of Them for Better Beats
- Sunwarper
- Aug 15
- 4 min read
The SP404 MK2 has a ton of useful effects for sound design, live performance, and beatmaking. But between the input effect and the 2 different kinds of bus effects, the routing can get a little confusing. The real power of the SP’s effects comes from how you route all of your samples into the bus effects.
In this guide, we’ll break down how bus effects work, the different routing options, and my go-to setup that makes everything sound better while keeping mixes clean.
What Are Bus Effects?
Bus effects are like audio routing lanes. You can send different samples through each one, with a dedicated effect on each bus, and control how those effects flow into each other before hitting your final mix.
The SP-404MKII has four main bus effects:
Bus 1 and 2 – Accessible with the "Bus FX" pad, perfect for performance effects.
Bus 3 and 4 – Accessible via the menu, better for mastering or final processing.
Every Sample can be set to Bus 1, Bus 2 and even no Bus. This is indicated by the sample pad's color. Here are the stock colors the SP is set to out of the box:
Bus 1: Yellow
Bus 2: Green
No Bus: White
You can customize the colors in the general settings.
Tonal and Performance Effects with Bus 1 & 2
Bus 1 and Bus 2 are where the SP404 MK2 really shines for creative shaping and live performance. Think of these as your hands-on buses, the ones you’ll be toggling and twisting in real time.
You can use them in two ways:
Tonal and Color Shaping
Add reverb to give a sample space and depth
Use delays for rhythmic echoes or to build atmosphere
Drop in the Isolator to cut lows or highs for mixing on the fly
Apply Vinyl Sim or Lofi effects to add grit and texture
Performance FX
The classic DJFX Looper for stutter effects, chops, and glitchy fills
Filter sweeps, beat repeats, and tape stop effects that add movement
Quick transitions when switching between patterns or resampled loops
Because Bus 1 and 2 are so immediate, I like to think of them as the “performance buses.” They let you color sounds as part of your mix, but also give you tactile control to push and pull your beat during a live set.
And that’s where routing comes in. How you set these up — either in parallel or serial — changes how these tonal and performance effects interact with each other.
Parallel vs. Serial Bus Routing
You can route Bus 1 and 2 into Bus 3 and 4 in two ways:
Parallel – Bus 1 and 2 stay separate. Great for keeping melodic sounds and drums unaffected by each other’s effects.
Serial – Bus 1 feeds into Bus 2. Useful for performance setups where you want a global effect over everything on Bus 2.
My approach:
Serial Routing
Bus 1: Melodic sounds (Reverb, Vinyl Sim, Lofi)
Bus 2: Drums and bass (Isolator, DJFX Looper)
Working in this way, Bus 1 can have expansive tonal fx on melodic samples, but the drums remain unaffected. From there, I can do performance fx on the WHOLE mix using bus 2.
Accessing and Setting Up Bus 3 and 4
Hit Shift + Pad 16 to access buses 3 and 4. From here, you can:
Change bus presets using the Value Encoder
Switch effects by highlighting EFX Type and turning Value Encoder
Adjust effect parameters with the right-most encoder
The Input Effect and Input Bus Routing
The input effect processes any incoming audio (hardware and mic). By default, it routes through Bus 1 → Bus 2 → Bus 3 → Bus 4.
You can change this in the Input Bus settings, switching it's bus effect to bus 2:
Routes external gear to Bus 2 while internal samples stay on Bus 1 for separate treatment
My Go-To Bus 3 & 4 "Sound Better" Chain
Bus 3: Cassette Sim
Drive: ~19 (Depending on your track's gain staging, you may want more or less)
Wow/Flutter: ~36 for movement
Age/Tone: Adjust for flavor
No “Catch”
Bus 4: Vinyl Sim 303 Compressor
Compressor: 50–60 depending on gain staging
Noise: 0
Wow/Flutter: Adjust as needed
Using Bus 3 and 4 for Resampling
If you’re resampling, buses 3 and 4 give you two extra effects to play with:
Warm Saturator
EQ for tonal shaping
More extreme Lofi processing
Why This Routing Works
This setup keeps melodic and rhythmic elements separate so your mix stays clean, while giving you full control for live performance. You can:
Add effects to drums without affecting melodies (or vice versa)
Glue everything together with a mastering chain
Switch between clean and “wrecked” mixes on the fly
Want to Go Deeper with the SP404 MK2?
If you want to master the SP404 MK2 and get the most out of its many features, check out my SP-404MKII Cheat Sheet & Quick Start Guide. You’ll learn:
Performance workflows
Resampling tricks
Essential effect setups
Get the guide here:
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