Best Local AI Background Music Generators (2026): Royalty-Free Instrumentals on Your GPU

Every YouTube video, game level, podcast intro and Twitch stream needs background music, and stock libraries or Suno subscriptions add up fast. In 2026 you can generate royalty-free instrumentals on your own PC instead, and some of the best options now run on a CPU or a 6 GB GPU. In this guide I compare the local background music generators worth using in November 2026, including the new Stable Audio 3 family, ACE-Step 1.5 in instrumental mode, Google’s Magenta RealTime 2 and MiniMax Music 3. You will get the exact model files and ComfyUI folders, prompt templates for each type of background track, how to make seamless loops, and a clear answer on which licenses let you monetise the music.

Quick Comparison Table

Background Music vs Song Generators

Song models such as YuE2 or MiniMax Music 3 are trained to put a vocal front and centre, with verses, choruses and big transitions. That is exactly what you do not want under a voiceover or a game level. Good background music is steady, has no sudden drops, leaves room in the mid frequencies for speech, and ideally loops. So for this guide I rank models on four things: instrumental quality, control over tempo and mood, length and looping, and license. Stable Audio 3 wins on the first three because it was trained for music, instruments and sound design rather than songs, while ACE-Step 1.5 wins on license.

1. Stable Audio 3: Best All-Round Instrumental Model

Stable Audio 3 (May 2026) is Stability AI’s new open model family. It uses a new SAME autoencoder (stereo, 44.1 kHz), supports text-to-audio, audio-to-audio editing and inpainting or continuation, and has stackable LoRAs for fine-tuning on your own style. Stability says it was trained only on licensed data (AudioSparx plus filtered CC Freesound audio). The open models are:

The 2.7B Large model is API only. For background music, Medium is the sweet spot: 120 seconds of audio takes well under a second on an H200 and, by my estimate from those numbers, a few seconds on an RTX 4070 to 5080 class card. It fits comfortably on 8 GB.

Stable Audio 3 in ComfyUI: Files and Folders

1. Update ComfyUI to the latest release (Nightly if the nodes are missing).
2. Download from Comfy-Org/stable-audio-3:
   • ComfyUI/models/checkpoints/stable_audio_3_medium.safetensors (post-trained, use with the Qwen reprompt)
   • ComfyUI/models/checkpoints/stable_audio_3_medium_base.safetensors (base, for your own detailed prompts)
   • ComfyUI/models/text_encoders/t5gemma_b_b_ul2.safetensors (required for all Stable Audio 3 workflows)
   • ComfyUI/models/text_encoders/qwen3.5_2b_bf16.safetensors (from Comfy-Org/Qwen3.5, only for the reprompt feature)
3. Press R to refresh, then open the Stable Audio 3.0 Medium template.
4. Type a short idea, set the duration in seconds, choose the category (Music, Instrument, SFX or One-shot), and turn on use_reprompt so Qwen expands your idea into a detailed prompt. Output goes to ComfyUI/output/audio/.

The Medium Base template skips the reprompt step, which is better when you already have a precise prompt with BPM and key.

Running Small-Music on a CPU

Small-Music is not in the ComfyUI templates yet, but the official repo runs it on any PC or Mac:

git clone https://github.com/Stability-AI/stable-audio-3.git
cd stable-audio-3
uv sync --extra ui
uv run python run_gradio.py --model small-music

You need to accept the license on the Hugging Face model page and log in with hf auth login first. Medium in this repo needs Flash Attention 2; ComfyUI does not, which is one more reason to use ComfyUI on Windows.

2. ACE-Step 1.5 Instrumental: Best for Commercial Use

ACE-Step 1.5 is primarily a song model (I cover it in detail in the text-to-song guide), but it makes very good instrumentals when you leave the lyrics empty or use [Instrumental]. Two things make it the best background music choice for creators who monetise: the code and weights are MIT, and the team says the training data is licensed, royalty-free or synthetic. It is also fast (a full track in under 10 seconds on an RTX 3090) and generates 10 seconds to 10 minutes, so you can make a full-length bed for a 10-minute video in one go.

Files for ComfyUI: the all-in-one ComfyUI/models/checkpoints/ace_step_1.5_turbo_aio.safetensors from Comfy-Org/ace_step_1.5_ComfyUI_files, used with the ACE-Step 1.5 Music Generation AIO template. On 16 GB or more, the XL Turbo split files sound richer (ComfyUI/models/diffusion_models/acestep_v1.5_xl_turbo_bf16.safetensors plus the Qwen encoders in ComfyUI/models/text_encoders/ and ComfyUI/models/vae/ace_1.5_vae.safetensors).

A prompt that reliably gives a clean background bed:

Tags: instrumental, lo-fi hip hop, 80 BPM, mellow Rhodes piano, soft vinyl crackle,
brushed drums, warm upright bass, no vocals, calm, study music
Lyrics: [Instrumental]
Duration: 180

Use “no vocals” in the tags as well as the instrumental tag. Without it, ACE-Step sometimes adds humming or vocal chops.

3. Magenta RealTime 2: Endless Live Music

Magenta RealTime 2 from Google is different: it streams music live, generating audio faster than it plays, and you can steer it with text prompts while it runs. That makes it ideal for long streams, game levels that never end and live performance. It comes in two sizes, mrt2_small (230M) and mrt2_base (2.4B). The small model runs in real time on any Apple Silicon Mac, base needs an M-series Pro or Max for real time, and both can run offline (not real time) on NVIDIA GPUs.

# Apple Silicon
uv venv --python 3.12 && source .venv/bin/activate
uv pip install "magenta-rt[mlx]"
mrt models init
mrt models download
mrt mlx generate --help

The repo also offers a C++ build, desktop apps and DAW plugins. Code is Apache 2.0; the v1 weights were CC BY 4.0, so check the MRT2 model card for the current weight terms before you use it commercially. Links: GitHub and Hugging Face.

4. MiniMax Music 3 Instrumental: Big Cinematic Tracks

MiniMax Music 3 (Aug 13, 2026) is built for full songs, but its [Instrumental] and [Solo] tags and structured caption make it excellent for cinematic and trailer music, where you want a build, a climax and an ending rather than a flat loop. It needs more VRAM than the others (16 GB with the INT8 DiT and text encoder, or GGUF DiT quants for 8-12 GB) and runs natively in ComfyUI from the MiniMax Music 3 Text to Music template. The files and folders are listed in my song model guide. Its Community License allows commercial use for companies under $20M revenue.

5. Older Models: MusicGen and Stable Audio Open

• MusicGen (Meta, 2023) still has the biggest community and melody conditioning, but the weights are CC BY-NC and quality is clearly behind Stable Audio 3.
• Stable Audio Open 1.0 (47 s) and Stable Audio Open Small (11 s) are now replaced by Stable Audio 3, which goes up to 2 minutes on Small and over 6 minutes on Medium.
• InspireMusic (Alibaba FunAudioLLM) is instrumental-only and Apache 2.0, a reasonable fallback if you need long-form instrumentals and Stable Audio’s license does not fit.

Prompt Templates by Use Case

Background music prompts work best when you state genre, BPM, key instruments, mood and what to avoid. These work with Stable Audio 3 (category Music) and ACE-Step 1.5 (add “instrumental, no vocals”):

Generate three or four seeds of the same prompt and pick the best. Changing the seed is cheaper than rewriting the prompt.

How to Make Seamless Loops

For games and streams you usually want a loop that repeats without a click. Here is the method that works with any model:

1. Ask for a loop and a fixed tempo in the prompt (“seamless loop, 90 BPM”).
2. Cut to whole bars. At 90 BPM in 4/4 one bar lasts 60 / 90 × 4 = 2.667 seconds, so 8 bars = 21.33 seconds. Trim from the start of a bar to the end of a bar.
3. Crossfade the seam. Overlap the end with the start using ffmpeg:

   ffmpeg -i track.wav -filter_complex "[0]atrim=0:21.33,asetpts=N/SR/TB[a];[0]atrim=21.33:22.33,asetpts=N/SR/TB[b];[b][a]acrossfade=d=1:c1=tri:c2=tri" loop.wav

4. Or use inpainting. Stable Audio 3 supports inpainting and continuation, so you can regenerate the last second so it leads back into the first.

Ducking Music Under a Voiceover

Even good background music fights with speech if it is too loud. Sidechain ducking lowers the music only while someone talks:

ffmpeg -i voice.wav -i music.wav -filter_complex "[1:a]volume=0.35[m];[m][0:a]sidechaincompress=threshold=0.03:ratio=8:attack=20:release=400[duck];[duck][0:a]amix=inputs=2:duration=first" mix.wav

To put the mixed audio on a video without re-encoding the picture, see my guide to adding sound effects and music to a short with ffmpeg. For the voiceover itself, Fish Audio Drama 3 and Voicebox both run locally.

Royalty-Free? The License Table

“Royalty-free” here means you do not pay per use, not that a platform’s content ID can never flag a track. Keep the prompt, seed and model version for every track you publish. This is not legal advice.

Which Model for Your Hardware

• No GPU, laptop or Mac: Stable Audio 3 Small-Music, or Magenta RealTime 2 small on Apple Silicon.
• 4-8 GB GPU: ACE-Step 1.5 turbo (LM off or 0.6B LM), Stable Audio 3 Medium (about 5-6.5 GB peak).
• 12-16 GB GPU: Stable Audio 3 Medium for loops and beds, ACE-Step 1.5 XL Turbo with offload for full tracks.
• 24 GB+: add MiniMax Music 3 fp16 for cinematic pieces.

Not sure what your card can handle in ComfyUI? My ComfyUI VRAM guide covers it, and the model folder cheat sheet shows where every file goes.

Frequently Asked Questions

What is the best free AI background music generator I can run locally?

Stable Audio 3 Medium for quality and control, and ACE-Step 1.5 if you need an MIT license for monetised content. Both are free and run natively in ComfyUI.

Can I generate background music without a GPU?

Yes. Stable Audio 3 Small-Music (433M) runs on a CPU and makes up to 2 minutes, and Magenta RealTime 2 small runs in real time on Apple Silicon.

Can I use AI background music on monetised YouTube videos?

With ACE-Step 1.5 (MIT), yes. With Stable Audio 3, yes if you or your company earn under $1M a year. With MiniMax Music 3, yes under $20M revenue. Not with MusicGen or other non-commercial models.

How long can local AI background music be?

ACE-Step 1.5 goes up to 10 minutes, Stable Audio 3 Medium to 380 seconds, and Magenta RealTime 2 streams without a limit. For longer videos, loop or chain tracks.

How do I stop the model adding vocals?

Write “instrumental, no vocals” in the prompt and use [Instrumental] as the lyrics in song models. In Stable Audio 3, choose the Music or Instrument category.

Can Stable Audio 3 make sound effects too?

Yes. Medium has an SFX category and there is a dedicated Small-SFX model. I compare it with Woosh and MOSS-SoundEffect in my text-to-SFX guide.

Final Thoughts

For most creators the simplest setup is Stable Audio 3 Medium in ComfyUI for loops and beds, plus ACE-Step 1.5 for full-length tracks you want to monetise without worrying about revenue limits. Add Magenta RealTime 2 if you stream or build games and want music that never repeats.

This is part two of my local AI audio series:

• Best Local Text-to-Song AI Models: full songs with vocals and lyrics (YuE2, MiniMax Music 3, ACE-Step 1.5 XL, HeartMuLa).
• Best Local Text-to-SFX AI Models: sound effects and foley from text or video.

Making the video too? See the best local AI video models, and LTX-2.5 on 16 GB if you want a video model that generates its own audio.

Sources

• Stable Audio 3 GitHub (models, params, VRAM table)
• ComfyUI docs: Stable Audio 3 workflow
• Comfy blog: Stable Audio 3 day-0 support
• Stable Audio 3 Small model card (license, training data)
• ACE-Step 1.5 GitHub
• ComfyUI docs: ACE-Step 1.5
• Magenta RealTime 2 GitHub
• ComfyUI docs: MiniMax Music 3
• IT-JIM: open-source music model comparison
• FFmpeg filters documentation (acrossfade, sidechaincompress)