Eighteen Sound design
Manifolded 2x21" band-pass IPAL™ powered subwoofer
- Drivers
- 2 × 21ID
21-inch LF driver · 1,800 W
Eighteen Sound 21ID 2Ω
2 Ω · 29–1600 Hz
No current price
- Fs
- 38Hz
- Xmax
- 14mm
- SPL
- 97dB
- Pe
- 1800W
- BL
- 25.2T·m
- Vd
- 2324cm³
- Qts
- 0.23
- Vas
- 143L
Manufacturer response and impedance data, with source and trace details below. The left and right arrow keys read every shown curve at a frequency, a twelfth of an octave at a time, or an octave with Shift. Escape clears the reading.
Curve provenanceInspect 2 traces
These plotted lines are Bits digitizations of manufacturer evidence, not new measurements. How provenance works
- Trace datasheet-response-trace-poc/v1
frequency response
Frequency response
99 plotted pointsMedium confidence670 selected pixels of 1,218 - Trace datasheet-response-trace-poc/v1
impedance
Impedance response
239 plotted pointsMedium confidence846 selected pixels of 1,310
Published graphs
Eighteen Sound 21ID is a 21-inch 2 ohm LF driver rated at 1800 W RMS. The validated T/S data includes Fs 38 Hz, Qts 0.23, Vas 143 L, Xmax 14 mm, sensitivity 97.2 dB, plus 2324 cm³ Vd and 158 EBP. bits tracks vendor pricing, datasheet links, simulator import data, and similar drivers from the same loudspeaker database.
The published T/S values agree with each other
Thiele/Small
- Fs
- 38Hz
- Qts
- 0.23
- Qes
- 0.24
- Qms
- 5.6
- Vas
- 143L
- Re
- 1.3Ω
- Le
- 1.08mH
Motor and cone
- BL
- 25.2T·m
- Sd
- 1660cm²
- Mms
- 489g
- Xmax
- 14mm
- Vd †
- 2324cm³
Power and response
- Sensitivity †
- 97.2dB
- Manufacturer sensitivity
- 94.2dB
- Power
- 1800W
- Nominal power
- 1800W
- Impedance
- 2Ω
- Range
- 29–1600Hz
- EBP †
- 158 · Leans vented
Size and mounting
- Diameter
- 545mm
- Cutout
- 492mm
- Bolt circle
- 520mm
- Depth
- 250mm
- Weight
- 13.6kg
Other published values
- Power Program
- 3600
Sensitivity shows 97.2 dB, calculated from the T/S values. Eighteen Sound publishes 94.2 dB, 3.0 dB apart.
† Calculated by bits from the published values
What this validation status means
Everything else Eighteen Sound lists
LF · Primary · 21″
- BL
- 25.2T·m
- Fs
- 38Hz
- Le
- 1.08mH
- Re
- 1.3Ω
- Sd
- 1660cm²
- Mms
- 489g
- Qes
- 0.24
- Qms
- 5.6
- Qts
- 0.23
- SPL
- 97.2dB
- Vas
- 143L
- Xmax
- 14mm
- Power
- 1800W
- Impedance
- 2Ω
- Sensitivity
- 94.2dB
- Low limit
- 29Hz
- Nominal power
- 1800W
- Power Program
- 3600
- Calculated sensitivity †
- 97.2dB
- High limit
- 1600Hz
- Manufacturer sensitivity
- 94.2dB
- Weight
- 13.6kg
- Diameter
- 545mm
- Depth
- 250mm
- Cutout
- 492mm
- Bolt circle
- 520mm
02
Designs
Cabinets for the 21ID: a design and a suggested box from Eighteen Sound, and plans builders have published.
All 21ID designsHow we find designsEighteen Sound’s design
From the maker, with plans to download
Eighteen Sound’s suggested box
From Eighteen Sound’s 21ID page
- Net volume
- 220L
- Tuning
- 40Hz
Eighteen Sound gives the volume and tuning; the port is sized for the driver when you open it.
Modelling the box in 00 Simulator…
03
Compare
Same-size drivers, compared with the 21ID. Clear differences are green when better and red when worse.
This driver21ID
Best price
–
Fs
38 Hz
Qts
0.23
Vas
143 L
BL
25.2 T·m
Xmax
14 mm
Sensitivity
97.2 dB
Power
1800 W
SB AudienceNERO-21SW1100D
£343.60Fs32 Hz −16%, better
Qts0.34 +48%, worse
Vas312.6 L +119%, worse
BL30 T·m +19%, better
Xmax12.2 mm −13%, worse
Sensitivity96.7 dB −0.5
SB AudienceROSSO-21SW800
£418.61Fs38 Hz –
Qts0.76 +230%, worse
Vas224.4 L +57%, worse
BL24.1 T·m −4%
Xmax11.4 mm −18%, worse
Sensitivity93.9 dB −3.3, worse
CelestionTSQ2145
£445.00Fs30 Hz −21%, better
Qts0.34 +50%, worse
Vas253.8 L +77%, worse
BL33.8 T·m +34%, better
Xmax15 mm +7%
Sensitivity94.8 dB −2.4, worse
RCFLF21X451
£448.61Fs28 Hz −26%, better
Qts0.37 +61%, worse
Vas385 L +169%, worse
BL30.5 T·m +21%, better
Xmax14 mm –
Sensitivity95.4 dB −1.8
Dayton AudioHTS545HE-4
£448.82Fs26 Hz −31%, better
Qts0.28 +22%, worse
Vas179 L +25%, worse
BL38.2 T·m +52%, better
Xmax21 mm +50%, better
Sensitivity92.5 dB −4.7, worse
RCFLF21N451
£475.00Fs30 Hz −21%, better
Qts0.26 +13%, worse
Vas375 L +162%, worse
BL34.5 T·m +37%, better
Xmax13 mm −7%
Sensitivity97.8 dB +0.6
Beyma21LEX1600ND
£475.00Fs30 Hz −21%, better
Qts0.29 +26%, worse
Vas305 L +113%, worse
BL36.6 T·m +45%, better
Xmax14 mm –
Sensitivity96.4 dB −0.8
B&C21SW115
£476.43Fs33 Hz −13%, better
Qts0.36 +57%, worse
Vas278 L +94%, worse
BL24.8 T·m –
Xmax14 mm –
Sensitivity96.3 dB −0.9
B&C21DS115
£484.80Fs32 Hz −16%, better
Qts0.21 −9%
Vas219 L +53%, worse
BL28.6 T·m +13%, better
Xmax15 mm +7%
Sensitivity97.2 dB –
Beyma21QLEX1600FE
£493.97Fs30 Hz −21%, better
Qts0.28 +22%, worse
Vas309 L +116%, worse
BL36.4 T·m +44%, better
Xmax13 mm −7%
Sensitivity96.5 dB −0.7
Eighteen Sound21NLW4100
£506.41Fs34 Hz −11%, better
Qts0.40 +74%, worse
Vas219 L +53%, worse
BL22.8 T·m −10%
Xmax15.2 mm +9%
Sensitivity95.1 dB −2.1, worse
Eighteen Sound21LW1400
£543.74Fs28 Hz −26%, better
Qts0.24 +4%
Vas385 L +169%, worse
BL33.5 T·m +33%, better
Xmax9.5 mm −32%, worse
Sensitivity97.5 dB –
No photo
Precision DevicesPD.2155-1N
£555.00Fs33 Hz −13%, better
Qts0.36 +57%, worse
Vas241 L +69%, worse
BL30 T·m +19%, better
Xmax14 mm –
Sensitivity95.7 dB −1.5
B&C21SW152
£585.00Fs32 Hz −16%, better
Qts0.30 +30%, worse
Vas200 L +40%, worse
BL32.5 T·m +29%, better
Xmax15 mm +7%
Sensitivity95.3 dB −1.9
Eighteen Sound21NLW9001
£587.88Fs31 Hz −18%, better
Qts0.34 +48%, worse
Vas272 L +90%, worse
BL23.8 T·m −6%
Xmax14 mm –
Sensitivity95.4 dB −1.8
Eighteen Sound21NLW9601
£593.90Fs41 Hz +8%
Qts0.32 +39%, worse
Vas123 L −14%, better
BL32.7 T·m +30%, better
Xmax14 mm –
Sensitivity96.1 dB −1.1
Eighteen Sound21NTLW5000
£595.00Fs30 Hz −21%, better
Qts0.32 +39%, worse
Vas300 L +110%, worse
BL25 T·m –
Xmax17.5 mm +25%, better
Sensitivity95.9 dB −1.3
Eighteen Sound21NLW4000
£608.33Fs29 Hz −24%, better
Qts0.37 +61%, worse
Vas305 L +113%, worse
BL30 T·m +19%, better
Xmax15 mm +7%
Sensitivity94.9 dB −2.3, worse
No photo
Precision DevicesPD.2160-1N
£799.00Fs35 Hz −8%
Qts0.30 +30%, worse
Vas177 L +24%, worse
BL43 T·m +71%, better
Xmax16 mm +14%, better
Sensitivity95.9 dB −1.3
B&C21IPAL
£863.28Fs37 Hz –
Qts0.21 −9%
Vas155 L +8%
BL19.1 T·m −24%, worse
Xmax22 mm +57%, better
Sensitivity97.6 dB –
FaitalPRO21XL3000
£878.34Fs32 Hz −16%, better
Qts0.22 −4%
Vas223.5 L +56%, worse
BL35.5 T·m +41%, better
Xmax17.7 mm +26%, better
Sensitivity97.3 dB –
Eighteen Sound21NLW9601C
No current priceFs38 Hz –
Qts0.29 +26%, worse
Vas140 L –
BL33.2 T·m +32%, better
Xmax14 mm –
Sensitivity96 dB −1.2
Eighteen Sound21LW2600
No current priceFs27 Hz −29%, better
Qts0.29 +26%, worse
Vas332 L +132%, worse
BL24.9 T·m –
Xmax14.6 mm +4%
Sensitivity95.6 dB −1.6
B&C21SW150
No current priceFs29 Hz −24%, better
Qts0.26 +13%, worse
Vas254 L +78%, worse
BL32.6 T·m +29%, better
Xmax15 mm +7%
Sensitivity95.6 dB −1.6
No current price
Fs33 Hz −13%, better
Qts0.36 +57%, worse
Vas241 L +69%, worse
BL30 T·m +19%, better
Xmax14 mm –
Sensitivity95.7 dB −1.5
Eighteen Sound21LW2500
No current priceFs29 Hz −24%, better
Qts0.37 +61%, worse
Vas305 L +113%, worse
BL30 T·m +19%, better
Xmax14 mm –
Sensitivity94.9 dB −2.3, worse
No current price
Fs35 Hz −8%
Qts0.34 +47%, worse
Vas266 L +86%, worse
BL31.3 T·m +24%, better
Xmax14 mm –
Sensitivity97.1 dB –
No photo
Precision DevicesPD.2155-1F
No current priceFs35 Hz −8%
Qts0.34 +47%, worse
Vas266 L +86%, worse
BL31.3 T·m +24%, better
Xmax14 mm –
Sensitivity97.1 dB –
Dayton AudioPSS545HE-4
No current priceFs29 Hz −24%, better
Qts0.27 +17%, worse
Vas212.2 L +48%, worse
BL35.5 T·m +41%, better
Xmax21 mm +50%, better
Sensitivity94.6 dB −2.6, worse
Eighteen Sound21NLW5300
No current priceFs31 Hz −18%, better
Qts0.32 +39%, worse
Vas325 L +127%, worse
BL31 T·m +23%, better
Xmax15.3 mm +9%
Sensitivity96.6 dB −0.6
Tune the match
Choose the published values that matter to your design. Size stays matched to this driver.
Qts
Qes
VasL
Xmaxmm
BLTm
No current price found. Pricing may appear after the next vendor refresh.