What are the odds of double crit on a WuWa echo?
12.82%, about 1 in 7.80 echoes (5★, +0 to +25).
The math
A +25 echo has 5 of the 13 substat types. No repeats, all types equally likely.
Possible sets: C(13, 5) = 1,287.
Sets with both crits: C(11, 3) = 165.
165 / 1,287 = 12.82%.
Other crit goals
| Goal | Chance per echo | Echoes per hit |
|---|---|---|
| Crit. Rate | 38.46% | 1 in 2.60 |
| At least 1 of Crit. Rate or Crit. DMG | 64.10% | 1 in 1.56 |
| Crit. Rate and Crit. DMG | 12.82% | 1 in 7.80 |
| Crit. Rate ≥ 8.1% and Crit. DMG ≥ 16.2% | 1.15% | 1 in 87 |
Roll values are separate rolls, so a minimum value multiplies the odds.
Echoes needed
| Echoes | |
|---|---|
| Average | 7.8 |
| Half of players | 6 or fewer |
| 9 in 10 players | 17 or fewer |
Each echo is a new roll. Misses do not raise the odds of the next echo.
Cost
Averages for the whole goal, after discard refunds (75% of EXP, 30% of Tuners).
| Route | Echoes | Tuners | Premium Tubes | Transducers |
|---|---|---|---|---|
| Max every echo | 7.8 | 288 | 77.2 | — |
| Tune & scrap (strict) | 78 | 666 | 52.5 | — |
| One echo + Data Modify | 1 | 50 | 28.6 | 4 |
Max every echo: tune every echo to +25, keep the first hit.
Tune & scrap (strict): scrap at the first tune that misses a goal stat.
Data Modify: reroll one +25 echo until it hits.
In Waveplates and money
| Route | Tacet runs | Days | Money value |
|---|---|---|---|
| Max every echo | 16 | 4 | $12 |
| Tune & scrap (strict) | 33.3 | 8.3 | $25 |
| One echo + Data Modify | 5.9 | 1.5 | $34–$63 |
1 Tacet Field run (60 Waveplates): about 24,155 Echo EXP (4.8 Premium Tubes) and 20 Premium Tuners. 240 Waveplates per day.
One run drops tubes and Tuners together, so the scarcer one sets the runs. Echo drops are not counted.
Money: a 60-Waveplate refill costs 60 Astrite (the first 2 each day). 1 pull = 160 Astrite. At the $99.99 Lunite pack, 1 Astrite ≈ $0.0124, 60 Waveplates ≈ $0.74, and 1 pull ≈ $1.98.
Other ways to buy Waveplates: Sage's Solvent Aid, $4.99 for 7 Crystal Solvent, is $0.71 per 60 when the shop offers it. The Lunite Subscription, $4.99 for 3,000 Astrite, is $0.10 per 60, for up to 3,000 Astrite a month.
Shops: a Premium Sealed Tube also sells for 250 Monnaie (Averardo Bank) or 50 Data Sets (Simulation Training Store, 25 max).
Drop data: community drop sheet, 1,697 Tacet Field runs at SOL3 Phase 8, versions 2.0–2.5.