Flow Music AI Simple vs Custom Mode: Which Should You Use?

Choose Simple in Flow Music AI when you have an idea to describe. Choose Custom when you already have lyrics or want to put the title, musical style, and words in separate fields. Instrumental is a separate choice available in either mode.

Both routes start in the Flow Music AI music generator. The useful question is how much of the song you have already decided. A one-sentence concept needs a different starting point from a finished verse and chorus.

This guide explains that choice, shows the same creative idea in both forms, and covers what to check before switching. Interface and input limits were checked on November 2, 2026. These are workflow recommendations, rather than an audio-quality comparison from generated test tracks.

Choose a mode from the material you already have

What you have	Starting point	What to prepare
A theme, scene, or feeling, with no finished words	Simple	A short description of the music and subject
Lyrics you want the song to use	Custom, Instrumental off	Title, Styles, and Lyrics
A detailed sound direction and a working song title	Custom	Separate the sound description from any words to sing
An idea for music without singing	Simple with Instrumental on	A concise musical brief
A named instrumental with a more detailed arrangement brief	Custom with Instrumental on	Title and Styles; lyrics are not required

Custom gives you separate inputs. That does not make it the better starting point for every task. If you are still deciding what the song should be about, the extra fields may simply create more decisions before you have a useful brief.

Concept illustration of two ways to organize a song idea; this is not a screenshot of the generator.

Use Simple when the idea is clearer than the words

Simple provides one description field. Start by stating the musical direction and the subject, then add one or two details that matter to the result. You do not need to invent a finished lyric just to begin.

For example, imagine a song about sending a postcard home after moving to a new city:

Warm acoustic pop about writing a postcard home after moving to a new city. Fingerpicked guitar, light brushed drums, an intimate lead vocal, and a hopeful chorus. Keep the pace unhurried and the mood affectionate rather than sad.

This brief gives the generator a subject and an arrangement direction. It leaves the exact words open. It is a useful route when you want to explore the idea before committing to individual lines.

To use it:

1. Open the generator and select Simple.
2. Leave Instrumental off if you want a vocal song.
3. Enter your description and check the character counter.
4. Check your account balance and the displayed generation cost before submitting.
5. Listen for whether the result communicates the intended subject and mood.

The Simple description currently allows 500 characters. Use that space to prioritize. A clear genre, a main instrument, and a specific emotional direction are easier to review than a long list of competing requests.

If you want music without singing, turn Instrumental on and replace the story instruction with the role of the music. For example, describe the texture and energy you need. The background music prompt guide covers that task in more detail.

Use Custom when you can separate sound from words

Custom displays Input Title, Styles, and Lyrics. Each field has a different job:

• Title: a working name that helps you identify the song.
• Styles: the sound you want, including genre, instruments, mood, and vocal direction.
• Lyrics: the words you want sung, with any useful section labels.

For the postcard idea, the same creative direction can become:

Title

Postcard Home

Styles

Warm acoustic pop, fingerpicked guitar, light brushed drums, intimate lead vocal, hopeful chorus, unhurried pace.

Lyrics — original example

[Verse]
I found a little shop beside the station
And bought a card with rooftops in the rain
I wrote about my room above the bakery
And how the morning bells all sound the same

[Chorus]
There is a light I carry from your window
There is a road that keeps me moving on
I send a little piece of where I landed
To tell you I am finding where I belong

The important change is responsibility: you have now supplied actual words instead of asking the generator to develop a topic. Put the instrumental and vocal description in Styles so the lyric field stays focused on the song text.

Choose Custom with Instrumental off, fill all three fields, and review them before generating. For a longer lyric, use the full lyrics-to-song walkthrough. That guide covers lyric preparation and revision; this one focuses on choosing and organizing the input.

Custom is not a promise that every line, section label, or arrangement instruction will be followed exactly. Judge the resulting performance by listening, and keep a copy of the words you submitted for comparison.

Instrumental changes what you need to supply

Instrumental is independent of Simple and Custom. You can request music without vocals from either starting point.

In Custom, the current form can proceed with Title and Styles when Instrumental is on, even with Lyrics empty. The Lyrics box remains visible, so its presence does not mean you must fill it. Leave it blank for a fresh instrumental brief and describe the arrangement in Styles.

For a vocal song, turn Instrumental off and provide the lyric text. If you intended singing but left the toggle on, correct that setting before submitting another request.

Choose the setting before generation. Switching the toggle in the form is not a way to remove a voice from an already generated audio file, and switching modes does not convert an existing instrumental into the same performance with singing.

Check these limits before moving a long draft

The following are current form limits, checked on November 2, 2026:

Input	Current limit
Simple description	500 characters
Custom title	80 characters
Custom Styles with V4	200 characters
Custom Styles with the other currently listed models	1,000 characters
Custom Lyrics with V4	3,000 characters
Custom Lyrics with the other currently listed models	5,000 characters

Follow the counter shown for your selected model if the interface changes. A longer allowance is space for information, rather than a reason to add more adjectives or repeat an instruction.

The description and lyric fields currently reuse the same text when you switch between Simple and Custom in the same form. That is convenient for keeping a draft visible, but it needs a check: a description can appear in the Lyrics box, and a lyric can reappear as a Simple description.

Before switching, copy your draft somewhere safe. After switching:

1. Read the destination field from the beginning.
2. Move sound instructions into Styles when using Custom.
3. Replace a description in Lyrics with actual song words if you want a vocal song.
4. Shorten a long lyric into a new brief before using Simple; do not assume that everything fits its 500-character limit.
5. Recheck Instrumental, the selected model, and any title or style still present.

These steps prevent an input mix-up. They do not preserve a previous melody or audio take.

Make the next attempt answer one question

The current generator displays 10 credits per generation request for either mode, and generation requires signing in with enough credits. Read the displayed cost and your available balance before each request; this is not a promise about a fixed number of completed songs per subscription.

Before spending another request, decide what you need to learn. Is the idea too broad? Simplify its subject. Are the words ready but the sound wrong? Keep the lyric copy and revise one part of Styles. Do you need an instrumental? Check that setting before rewriting the entire brief.

Keep the input and a short note about what you changed. Separate requests can produce different performances, so a change in the result does not establish that one mode always sounds better.

Once you have a version worth keeping, follow the MP3 download and file-check guide. For client or commercial work, review the current plan information and Terms of Service for your intended use; ask support if a requirement is unclear.

Start with the material you have: describe an idea in Simple, or organize prepared words and sound in Custom. Then open Flow Music AI and check the form before generating.

Sources: the live Flow Music AI generator, plan section, and Terms of Service linked above. Workflow, input limits, and displayed generation cost checked November 2, 2026. No generated audio was used to claim a quality advantage for either mode.