# 2XB303 Acid Bass Loop Maker — Electro Acid Synth Sequencer

> Electro acid bass synth sequencer for creating techno, house, and EDM melodies. (iPhone/iPad app by Rob Wilmot.)

- Source: https://appshunter.io/ios/app/2xb303-acid-bass-loop-maker/id1288067698 (this page in markdown: same URL + `.md`)
- Developer: [Rob Wilmot](https://appshunter.io/developer/520672432)
- Category: Music, Productivity
- Price: $3.99
- Rating: 4.70/5 from 57 App Store ratings · 41 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.6 · 16 MB
- Languages: American English
- Released: 2018-07-29
- Data updated: 2026-09-04
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/2xb303-acid-bass-loop-maker/id1288067698/reviews.md

## What is 2XB303 Acid Bass Loop Maker?

A creative bass synth sequencer for creating electro melodies or dirty phat & funky pure acid techno 303 style basslines. With LIVE CONTROL feature to trigger and transpose both sequences and new synth pad layer. Record and export your audio loops.
Inspired by the acid house music scene. An IOS exclusive, compared to a modern equivalent to Rebirth (Rebirth was a popular tb - 303 clone a decade ago). 
Look at the video tutorial for a how-to guide. Listen to what you can create easily with 2XB303.
Create electro, house, techno, edm  or synth sequences using standard step functions as seen on various sequencers like the Roland SH 101 synthesizer. 
Built in pad layer than follows pitch. Transpose and trigger sequence even with MIDI
Your synth sequences can also be generated randomly, shuffled or modify just notes.
Easily capture whatever you hear and export to AudioShare, Audio-Copy, Email or iTunes Shared Folder. 
Support for Audiobus 3 routing, Ableton Link, IAA (Inter App Audio)
Tweaking cut-off & decay Env-Mod & glide & accent etc for that classic sweet-spot acid growl Tap to dials to swipe up & down for fine adjustment of knobs.

The sound was first compared to a Cyclone TT - 303 synthesizer & tweaked to extend sound shaping beyond a just bass maker. Waves have optional harmonic version, noise, LFO, glide speed & PHAT/ BASS, and great effects. This is designed to give pure electro music creativity beyond an acid synth 303 bass maker to create dynamically fluctuating overlaying electronic patterns. A good addition to any electro, drum and bass, acid, techno, house and any other EDM fans

LIVE CONTROL feature:
Use the keyboard for the following cool tricks:
[Sequence/Control/Transpose]: Transpose both channels simultaneously while playing. Now ability to trigger sequence too, with synth pad layer. (optional and 22 sounds)
[Sequence/Control/Pattern]:  Instantly switch to a saved sequence while playing. Keys correspond to stored program numbers, starting from the current program thats loaded (key 1 is your current program, key 2 is current program+1). Highlighted keys show stored programs. This is great for building up live tracks, or instant crossfading between programs. You can also "Hold settings" so it locks settings like effects.
 

MOD:
LFO auto control low pass CUT-OFF and/or PITCH. The pitch level can give a vintage synthesiser effect subtly detuning with low SPEED or faster for chaotic random pitches.

EFFECTS (Global/master are in yellow.)
OVERDRIVE, COMPRESSION adjusts threshold, ratio, & gain. This is a global effect.
ECHO tempo synced with feedback & wetness. 
SAVE ALL. When not playing, save to memory.

SYNCING
Ableton Link syncs with apps .Enable for precise timing without syncing. Press LINK button at the bottom for settings.
MIDI sync with External, Virtual or Audiobus.  2XB 303 can be master or slave. ( any simple class-compliant USB should work but some may need to be power assisted)  
Virtual MIDI In is always on. If you send from another app AND receive MIDI clock then you will be receiving both MIDI CLOCKS. Choose only one unless you want double tempo (which can be interesting).
While Ableton Link is enabled you can send clock. This means you can use one app to control 2XB303 synth alongside external hardware sequencers
MIDI note data is sent out on each channel

AUDIO
Record a fixed length, default to 32 steps. Can be changed in settings.
Arming the sampling with CAPTURE (flashing). Starts at counter 1 (ON). 
PLAY CAP to listen to your super cool sampled acid synthesiser loop.

Audiobus 3 and IAA (Inter App Audio) Support. Route audio to mix or record into other applications
Audio can be routed via IAA into apps like Apple's Garageband. 
Garageband will also sync your sequence for excellent multi-track recording.

To save you press "Save all", it then flashes. Now choose destination ("!" means its occupied ) then press "Save All" to confirm.

## Key features

- Bass synth sequencer
- Live control for sequences and pads
- Audio loop recording and export
- Random sequence generation
- Tweakable synth parameters
- MIDI and Ableton Link syncing
- Global effects: Overdrive, Compression, Echo

## Recent user reviews (10 of 41)

All indexed reviews: https://appshunter.io/ios/app/2xb303-acid-bass-loop-maker/id1288067698/reviews.md

### 5/5 — Filthy

*2026-08-26*

Love it

### 4/5 — “ACCIIIDD”

*2026-06-27*

Fun very good for the price, it’s peanuts after-all but the mixer needs more volume

### 5/5 — Great app

*2026-05-15*

Honestly just the best

### 5/5 — Energy Dance

*2024-10-31*

Very nice app for the price got lot of potential

### 5/5 — No sound at the moment

*2024-08-26*

I’m not getting any sound. Have checked the phone volume and that’s on. Any ideas? Thanks.

### 4/5 — Still trying to figure it out

*2024-07-04*

It’s been fun using the presets and random sequences. I really dig this ap.

### 4/5 — Fun and useful, just one problem…

*2024-02-08*

I don’t know if anyone else has experienced this with this app but the metronome does not sync up to the sequencer at all, it doesn’t even play at the same tempo. Otherwise though, I’ve definitely enjoyed it. I just wish I could use the metronome with it

**Developer response:** Should be fixed now.
Old version just needs link enabled.

### 1/5 — No sound

*2023-06-02*

Unable to get sound on iPhone 11

**Developer response:** Usually the mute button is left on the side of the phone with this kind of problem. Check that please. If still a problem email at info@beatsnbobs.com
Thank you

### 3/5 — Dated, but fairly easy to use and understand

*2023-01-30*

This is actually what the 303 and its ilk should be like… too bad it doesn’t do well with daws… needs better daw support…

### 3/5 — Problème

*2022-12-07*

L’appli est bien, mais je n’arrive pas avoir plus que deux Chanel. Pouvez-vous m’aider ?

## Frequently asked questions about 2XB303 Acid Bass Loop Maker

### What kind of music can I create with this app?

This app is designed for creating electro melodies, dirty phat & funky pure acid techno 303 style basslines, and other electronic music patterns. It's suitable for genres like electro, house, techno, drum and bass, and general EDM.

### What are the key features for live performance?

The app includes a LIVE CONTROL feature that allows you to trigger and transpose both sequences and a new synth pad layer in real-time. You can also instantly switch to saved sequences while playing, making it great for building live tracks.

### How can I export my creations?

You can easily capture and export your audio loops to various destinations including AudioShare, Audio-Copy, Email, or the iTunes Shared Folder. The app also supports Audiobus 3 routing, Ableton Link, and IAA (Inter App Audio) for seamless integration with other music apps.

### Is this app compatible with other music software?

Yes, the app supports syncing with other applications via Ableton Link for precise timing without dedicated syncing. It also supports MIDI sync with external, virtual, or Audiobus connections, allowing it to act as either a master or slave device.

### What sound shaping options are available?

You can extensively tweak parameters like cut-off, decay, Env-Mod, glide, and accent for that classic acid growl. The synth waves have optional harmonic versions, noise, LFO control, glide speed, and PHAT/BASS settings, along with great effects like overdrive, compression, and echo.

## Version history (last 5 releases)

### 4.2 — 2025-06-09

Fixed a bug introduced in last version that messed up the loop recording on some phones that also messed up the UI connections. (Sorry bout that!)
Also, as this app was released before Apple's IOS files app was introduced, it used an old system of iTunes file sharing. That has now been removed and instead your loops can be all saved in 2XB303 iOS Files folder, also incrementally the Export section . You can keep them stored in there for later if you have a nice sounding loop you want to keep. You can access them in iOS Files to copy , paste , rename etc.
Also fixed some other bugs

### 4.1 — 2025-05-30

Improved UI fo iPhone mainly (easier to read)

### 4 — 2025-05-29

Added saving of auto pad sounds settings to each pattern.
Updated core code
improved loop
better interruption crash
other crashes and UI fixes

### 3.2 — 2022-09-06

Fixed a bug where pitch wasn’t playing on step edit while it wasn’t running.
Changed program loading so if it sees an empty slot, it doesn’t do anything. It will keep the current program. Before it crashed the memory loading silently even though it didn’t ruin the saves.

### 3 — 2021-08-11

It has been a while since this was updated so I hope you enjoy some of these updates and added features.
Updated Audiobus
Updated Ableton Link (includes remote start/stop)
Fixed audio level on channel 2 being louder
Balanced audio for drum sounds on metronome drum backing
Fixed Note On  and Note Off from MIDI so this should hold note with a glide
Added Midi control of transpose using chosen channel. (Found in Settings/Midi)
Added Sequence Trigger from transposing with 2XB303 or MIDI (Found in Sequence/Control)
Added a new AutoPad sound layer that uses first note it finds in Channel 1 sequence  to play a selected pad sound as backing track. (Found in Sequence/Control, On//Off and Sound 1-22). You can adjust volume in Mixer section. This can give some great results used with transpose in Control section.
Increase screen space for MIDI ports
Allowed editing of step while running. Just use counter -/+ buttons, in Edit mode and it freezes selected step to where you move to. Resumes following sequence by pressing Edit Menu again.
Add Info links etc like other apps - email link and video demo link
Auto initialise empty memory slot as it was confusing before keeping the older program loaded.

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All apps by Rob Wilmot: https://appshunter.io/developer/520672432

## Related topics

[2xb303 acid bass loop maker](https://appshunter.io/ios/topics/2xb303-acid-bass-loop-maker) · [acid](https://appshunter.io/ios/topics/acid)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-04.*