Eighteen Sound design
Manifolded 2x21” band-pass subwoofer
- Drivers
- 21NLW9000or 21LW1400or 21NLW9600
The plans name the earlier 21NLW9000.
21-inch LF driver · 1,800 W
Eighteen Sound 21NLW9001 4Ω
25–1500 Hz
No price for delivery to the UK
- Fs
- 31Hz
- Xmax
- 14mm
- SPL
- 95dB
- Pe
- 1800W
- BL
- 23.8T·m
- Vd
- 2327cm³
- Qts
- 0.34
- Vas
- 272L
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/v2
frequency response
Frequency response
240 plotted pointsSource file SHA-256 01fe24105abd…Medium confidence1,981 selected pixels of 2,591 - Trace datasheet-response-trace-poc/v2
impedance
Impedance response
240 plotted pointsSource file SHA-256 01fe24105abd…Medium confidence646 selected pixels of 903
Published graphs
Eighteen Sound 21NLW9001 is a 21-inch 4 ohm LF driver rated at 1800 W RMS. The validated T/S data includes Fs 31 Hz, Qts 0.34, Vas 272 L, Xmax 14 mm, sensitivity 95.4 dB, plus 2327 cm³ Vd and 84 EBP. bits tracks UK, EU and US shop prices, price movement, datasheet links, simulator import data, and similar drivers, with a current best price of £586.79.
The published T/S values agree with each other
Thiele/Small
- Fs
- 31Hz
- Qts
- 0.34
- Qes
- 0.37
- Qms
- 4.5
- Vas
- 272L
- Re
- 2.9Ω
- Le
- 2.20mH
Motor and cone
- BL
- 23.8T·m
- Sd
- 1662cm²
- Mms
- 375g
- Xmax
- 14mm
- Vd †
- 2327cm³
Power and response
- Sensitivity †
- 95.4dB
- Manufacturer sensitivity
- 95dB
- Power
- 1800W
- Nominal power
- 1800W
- Impedance
- 4Ω
- Range
- 25–1500Hz
- EBP †
- 84 · Sealed or vented
Size and mounting
- Diameter
- 545mm
- Cutout
- 492mm
- Bolt circle
- 520mm
- Depth
- 250mm
- Weight
- 13.4kg
Other published values
- Power Program
- 3600
† Calculated by bits from the published values
What this validation status means
Everything else Eighteen Sound lists
LF · Primary · 21″
- BL
- 23.8T·m
- Fs
- 31Hz
- Le
- 2.20mH
- Re
- 2.9Ω
- Sd
- 1662cm²
- Mms
- 375g
- Qes
- 0.37
- Qms
- 4.5
- Qts
- 0.34
- SPL
- 95.4dB
- Vas
- 272L
- Xmax
- 14mm
- Power
- 1800W
- Impedance
- 4Ω
- Sensitivity
- 95dB
- Low limit
- 25Hz
- Nominal power
- 1800W
- Power Program
- 3600
- Calculated sensitivity †
- 95.4dB
- High limit
- 1500Hz
- Manufacturer sensitivity
- 95dB
- Weight
- 13.4kg
- Diameter
- 545mm
- Depth
- 250mm
- Cutout
- 492mm
- Bolt circle
- 520mm
02
Designs
Cabinets for the 21NLW9001: a design and a suggested box from Eighteen Sound, and flatpack kits of the Manifolded 2x21” band-pass subwoofer.
All 21NLW9001 designsHow we find designsEighteen Sound’s design
From the maker, with plans to download
Cut in the UKEighteen Sound’s suggested box
From Eighteen Sound’s 21NLW9001 page
- Net volume
- 300L
- Tuning
- 33Hz
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 21NLW9001. Clear differences are green when better and red when worse.
This driver21NLW9001
Best price
£586.79
Fs
31 Hz
Qts
0.34
Vas
272 L
BL
23.8 T·m
Xmax
14 mm
Sensitivity
95.4 dB
Power
1800 W
Dayton AudioPSS555-8
£193.74 · 67% less, betterFs28 Hz −11%, better
Qts0.33 –
Vas444 L +63%, worse
BL29.7 T·m +25%, better
Xmax11 mm −21%, worse
Sensitivity96.4 dB +1
SB AudienceNERO-21SW1100D
£343.60 · 41% less, betterFs32 Hz +3%
Qts0.34 –
Vas312.6 L +15%, worse
BL30 T·m +26%, better
Xmax12.2 mm −13%, worse
Sensitivity96.7 dB +1.3
SB AudienceROSSO-21SW800
£417.84 · 29% less, betterFs38 Hz +23%, worse
Qts0.76 +124%, worse
Vas224.4 L −18%, better
BL24.1 T·m –
Xmax11.4 mm −18%, worse
Sensitivity93.9 dB −1.5
Beyma21QLEX1600FE
£425.00 · 28% less, betterFs30 Hz −3%
Qts0.28 −18%, better
Vas309 L +14%, worse
BL36.4 T·m +53%, better
Xmax13 mm −7%
Sensitivity96.5 dB +1.1
CelestionTSQ2145
£445.00 · 24% less, betterFs30 Hz −3%
Qts0.34 –
Vas253.8 L −7%
BL33.8 T·m +42%, better
Xmax15 mm +7%
Sensitivity94.8 dB −0.6
RCFLF21X451
£448.61 · 24% less, betterFs28 Hz −10%
Qts0.37 +9%
Vas385 L +42%, worse
BL30.5 T·m +28%, better
Xmax14 mm –
Sensitivity95.4 dB –
Beyma21LEX1600ND
£475.00 · 19% less, betterFs30 Hz −3%
Qts0.29 −15%, better
Vas305 L +12%, worse
BL36.6 T·m +54%, better
Xmax14 mm –
Sensitivity96.4 dB +1
RCFLF21N451
£475.00 · 19% less, betterFs30 Hz −3%
Qts0.26 −24%, better
Vas375 L +38%, worse
BL34.5 T·m +45%, better
Xmax13 mm −7%
Sensitivity97.8 dB +2.4, better
B&C21SW115
£475.55 · 19% less, betterFs33 Hz +6%
Qts0.36 +6%
Vas278 L –
BL24.8 T·m +4%
Xmax14 mm –
Sensitivity96.3 dB +0.9
B&C21DS115
£483.91 · 18% less, betterFs32 Hz +3%
Qts0.21 −38%, better
Vas219 L −19%, better
BL28.6 T·m +20%, better
Xmax15 mm +7%
Sensitivity97.2 dB +1.8
Eighteen Sound21NLW4100
£505.48 · 14% less, betterFs34 Hz +10%
Qts0.40 +18%, worse
Vas219 L −19%, better
BL22.8 T·m −4%
Xmax15.2 mm +9%
Sensitivity95.1 dB –
No photo
Precision DevicesPD.2155-1N
£555.00 · 5% less, betterFs33 Hz +6%
Qts0.36 +6%
Vas241 L −11%, better
BL30 T·m +26%, better
Xmax14 mm –
Sensitivity95.7 dB –
B&C21SW152
£585.00 · Same priceFs32 Hz +3%
Qts0.30 −12%, better
Vas200 L −26%, better
BL32.5 T·m +37%, better
Xmax15 mm +7%
Sensitivity95.3 dB –
Eighteen Sound21NLW9601
£592.80 · 1% moreFs41 Hz +32%, worse
Qts0.32 −6%
Vas123 L −55%, better
BL32.7 T·m +37%, better
Xmax14 mm –
Sensitivity96.1 dB +0.7
Eighteen Sound21NTLW5000
£595.00 · 1% moreFs30 Hz −3%
Qts0.32 −6%
Vas300 L +10%, worse
BL25 T·m +5%
Xmax17.5 mm +25%, better
Sensitivity95.9 dB +0.5
Eighteen Sound21NLW4000
£607.21 · 3% moreFs27 Hz −13%, better
Qts0.38 +12%, worse
Vas380 L +40%, worse
BL20 T·m −16%, worse
Xmax15 mm +7%
Sensitivity94.9 dB −0.5
No photo
Precision DevicesPD.2160-1N
£799.00 · 36% more, worseFs35 Hz +13%, worse
Qts0.30 −12%, better
Vas177 L −35%, better
BL43 T·m +81%, better
Xmax16 mm +14%, better
Sensitivity95.9 dB +0.5
EminenceNSW6021-124
£912.88 · 56% more, worseFs31 Hz –
Qts0.32 −6%
Vas224.6 L −17%, better
BL30.5 T·m +28%, better
Xmax21 mm +50%, better
Sensitivity95 dB –
No current price
Fs35 Hz +13%, worse
Qts0.34 –
Vas266 L –
BL31.3 T·m +32%, better
Xmax14 mm –
Sensitivity97.1 dB +1.7
No photo
Precision DevicesPD.2155-1F
No current priceFs35 Hz +13%, worse
Qts0.34 –
Vas266 L –
BL31.3 T·m +32%, better
Xmax14 mm –
Sensitivity97.1 dB +1.7
No current price
Fs33 Hz +6%
Qts0.36 +6%
Vas241 L −11%, better
BL30 T·m +26%, better
Xmax14 mm –
Sensitivity95.7 dB –
Eighteen Sound21LW2500
No current priceFs29 Hz −6%
Qts0.37 +9%
Vas305 L +12%, worse
BL30 T·m +26%, better
Xmax14 mm –
Sensitivity94.9 dB −0.5
Eighteen Sound21LW2600
No current priceFs27 Hz −13%, better
Qts0.29 −15%, better
Vas332 L +22%, worse
BL24.9 T·m +5%
Xmax14.6 mm +4%
Sensitivity95.6 dB –
Eighteen Sound21NLW5300
No current priceFs31 Hz –
Qts0.32 −6%
Vas325 L +19%, worse
BL31 T·m +30%, better
Xmax15.3 mm +9%
Sensitivity96.6 dB +1.2
CelestionNTR21-5010JD
No current priceFs32 Hz +4%
Qts0.32 −6%
Vas276.7 L –
BL33.9 T·m +42%, better
Xmax9 mm −36%, worse
Sensitivity96.4 dB +1
P.AudioSD21-125XB
No current priceFs35 Hz +13%, worse
Qts0.38 +12%, worse
Vas345.6 L +27%, worse
BL30.4 T·m +28%, better
Xmax11.3 mm −20%, worse
Sensitivity97.7 dB +2.3, better
Eighteen Sound21NLW9601C
No current priceFs38 Hz +23%, worse
Qts0.29 −15%, better
Vas140 L −49%, better
BL33.2 T·m +39%, better
Xmax14 mm –
Sensitivity96 dB +0.6
Eighteen Sound21ID
No current priceFs38 Hz +23%, worse
Qts0.23 −32%, better
Vas143 L −47%, better
BL25.2 T·m +6%
Xmax14 mm –
Sensitivity97.2 dB +1.8
B&C21SW150
No current priceFs29 Hz −6%
Qts0.26 −24%, better
Vas254 L −7%
BL32.6 T·m +37%, better
Xmax15 mm +7%
Sensitivity95.6 dB –
Sica21 S 4 PL
No current priceFs35 Hz +12%, worse
Qts0.30 −12%, better
Vas255 L −6%
BL36.1 T·m +52%, better
Xmax5.2 mm −63%, worse
Sensitivity97.4 dB +2, better
Tune the match
Choose the published values that matter to your design. Size stays matched to this driver.
Qts
Qes
VasL
Xmaxmm
BLTm
None of the shops we track lists delivery to the UK at checkout.