Why Sume Music is $0.125 a track: Lyria list plus 25 percent

Sume bills $0.125 per Music 1.0 or Music Router track because the catalog applies a 1.25 multiplier to the provider list price, and for Lyria 3.5 that list price is $0.10. The Music Router schema says so directly: provider list times 1.25 per audio on every Music Router model, with the list shown for reference.

The price is per generation, not per second or per character, which fits the product: the Music 1.0 docs state there is no duration field, so the bill cannot depend on length. Prices below were checked 2026-10-10 against the docs and the catalog schema.

Where can you see the numbers?

Each row in GET /v1/music-router/models has pricing.list_usd_micros_per_audio (the provider list, for reference) and pricing.billable_usd_micros_per_audio (what Sume charges), plus a billable_formula string. Micros are millionths of a dollar, so 100000 micros is $0.10 and 125000 micros is $0.125.

What does the fixed price cover?

One accepted generation, whatever the prompt length up to 5,000 characters. It also covers an optional public HTTPS image_url. It does not cover repeated attempts: each new request is a new generation at the same price, and there is no seed to reproduce a track. A request rejected before generation, such as a duration field or a non-empty negative_prompt, returns a 400 and never reaches the model.

• Prompt of 100 characters or 5,000: same price.
• Two takes: $0.25.
• A 400 error for a rejected field is not a generation.

Do the three router ids differ in price?

No. sume/music-auto, lyria-3.5 and lyria-3-pro share the same fixed billable price, so choosing between them is about sound and repeatability, not cost. sume/music-auto resolves to lyria-3.5 today and may move without notice, so log job.request.routed_model for each track.

What does this mean for a budget?

Budget by takes, not seconds. If you keep one take in three, a kept track costs $0.375; add the fixed $0.01 for each timeline step when you join the music to a voiceover. For long soundtracks, the music docs and a stored page cover looping or concatenating, which adds a $0.01 timeline job rather than another generation.

Worked example for a month of music

A small studio makes 12 explainers a month and wants three candidate tracks per video, keeping one. That is 36 generations, so 36 x $0.125 = $4.50 a month, and each kept track effectively costs $0.375. If a policy rejection happens before generation it does not make a track; a rejected request that reaches no model is not a generation. Add the timeline join at $0.01 per video if you mix the music under narration: 12 x $0.01 = $0.12.

Compare that with a larger campaign of 200 tracks, which is $25.00 at the fixed price. The per-track number never changes with length or prompt size, which makes the budget easy to check against the invoice. If your invoice shows a different per-track amount, read the live catalog row first and compare it with the docs.