← Back to Dayton Audio - 18" Ultimax II Subwoofer - UMII18-22
Where the figures for UMII18-22 come from
I take every figure from Dayton Audio's own product page or datasheet where I can. This lists where each figure on the UMII18-22 page came from.
- 26 from Dayton Audio's product page
- 4 from Dayton Audio's datasheet
- 3 worked out from Dayton Audio's figures
- 1 my estimate
- 4 from NB Audio's listing
General
| Driver type | Subwoofer | NB Audio's listing |
|---|---|---|
| Nominal size | 18" | NB Audio's listing |
| Nominal impedance | 2+2Ω | Maker's product page |
| Series | Ultimax | NB Audio's listing |
| Power handling (RMS) | 1,200 W | Maker's product page |
| Power handling (program) | 2,400 W | Maker's product page |
| Sensitivity | 90.7 dB | Maker's product page |
| Frequency range | 20 – 500 Hz | Maker's product page |
| Suggested alignment | Sealed | NB Audio's listing |
Thiele/Small parameters
| Resonant frequency (Fs) | 22 Hz | Maker's product page |
|---|---|---|
| DC resistance (Re) | 4.2 Ω | Maker's product page |
| Voice coil inductance (Le) | 1.15 mH | Maker's product page |
| Mechanical Q (Qms) | 2.53 | Maker's product page |
| Electrical Q (Qes) | 0.67 | Maker's product page |
| Total Q (Qts) | 0.53 | Maker's product page |
| Equivalent volume (Vas) | 248.2 L | Maker's product page |
| Compliance (Cms) | 0.124 mm/N | Maker's product page |
| Moving mass (Mms) | 420 g | Maker's product page |
| Mechanical resistance (Rms) | 22.95 kg/s | Worked out from the maker's figures |
| Force factor (Bl) | 19.2 T·m | Maker's product page |
| Effective piston area (Sd) | 1,184 cm² | Maker's product page |
| Linear excursion (Xmax, one-way) | 28 mm | Maker's product page |
| Displacement volume (Vd) | 3,315 cm³ | Worked out from the maker's figures |
| Efficiency bandwidth product (EBP) | 32.84 | Worked out from the maker's figures |
Mounting
| Overall diameter | 470 mm | Maker's datasheet |
|---|---|---|
| Cutout diameter (suggested) | ≈ 428.2 mm | My estimate, from the maker's drawing |
| Mounting depth | 228.5 mm | Maker's product page |
| Flange thickness | 10.5 mm | Maker's datasheet |
| Bolt circle diameter | 447 mm | Maker's datasheet |
| Mounting holes | 8 | Maker's product page |
| Mounting hole diameter | 6.5 mm | Maker's datasheet |
| Voice coil diameter | 76 mm | Maker's product page |
| Weight | 21.59 kg | Maker's product page |
Materials
| Cone | Carbon Fibre | Maker's product page |
|---|---|---|
| Surround | Rubber | Maker's product page |
| Voice coil former | Aluminium | Maker's product page |
| Basket | Cast Aluminium | Maker's product page |
| Magnet | Ferrite | Maker's product page |
What the labels mean
- Maker's product page: copied from the maker's product page.
- Maker's datasheet: read off the maker's own datasheet or drawing.
- Worked out from the maker's figures: Vd = Sd × Xmax, EBP = Fs ÷ Qes.
- My estimate, from the maker's drawing: measured off the maker's drawing, usually within ±0.3 mm (up to ±0.5). The suggested cutout is the basket's width on the drawing plus 1 mm of clearance (1.5 mm on drivers over 200 mm). Measure before you cut.
- NB Audio's listing: how I've filed it in the store.
Check them yourself: Dayton Audio UMII18-22 Specification Sheet