REDCATT81FHW
£28.47 · 15% more, worseFs39 Hz −34%, better
Qts0.52 −5%
Vas21.5 L +7%
BL8.3 T·m −19%, worse
Xmax6.1 mm −6%
Sensitivity85.5 dB −5, worse
8-inch LF driver · 51 mm voice coil · 150 W
GRS 8PT-8 8Ω
8 Ω · 55–9000 Hz
£24.68
SteadyParts Express · 240 in stock · Ships from United States · All 2 offers
- Fs
- 59Hz
- Xmax
- 6.5mm
- SPL
- 91dB
- Pe
- 150W
- BL
- 10.2T·m
- Vd
- 138cm³
- Qts
- 0.55
- Vas
- 20L
GRS 8PT-8 is an 8-inch 8 ohm LF driver rated at 150 W RMS. The validated T/S data includes Fs 59 Hz, Qts 0.55, Vas 20.1 L, Xmax 6.5 mm, sensitivity 90.5 dB, plus 138 cm³ Vd and 100 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 £24.68.
The published T/S values agree with each other
Thiele/Small
- Fs
- 59Hz
- Qts
- 0.55
- Qes
- 0.59
- Qms
- 9.9
- Vas
- 20.1L
- Re
- 7.1Ω
- Le
- 1.50mH
Motor and cone
- BL
- 10.2T·m
- Sd
- 213cm²
- Mms
- 23g
- Xmax
- 6.5mm
- Vd †
- 138cm³
- Voice coil
- 51mm
Power and response
- Sensitivity †
- 90.5dB
- Manufacturer sensitivity
- 92dB
- Power
- 150W
- Impedance
- 8Ω
- Range
- 55–9000Hz
- EBP †
- 100 · Sealed or vented
Size and mounting
- Diameter
- 208.8mm
- Cutout
- 181.1mm
- Bolt circle
- 196.8mm
- Depth
- 95.0mm
Other published values
- Cms
- 0.31mm/N
- Power Peak
- 300
Sensitivity shows 90.5 dB, calculated from the T/S values. GRS publishes 92.0 dB, 1.5 dB apart.
† Calculated by bits from the published values
What this validation status means
Everything else GRS lists
LF · Primary · 8″
- BL
- 10.2T·m
- Fs
- 59Hz
- Le
- 1.50mH
- Re
- 7.1Ω
- Sd
- 213cm²
- Cms
- 0.31mm/N
- Mms
- 23g
- Qes
- 0.59
- Qms
- 9.9
- Qts
- 0.55
- SPL
- 90.5dB
- Vas
- 20.1L
- Xmax
- 6.5mm
- Power
- 150W
- Impedance
- 8Ω
- Power Peak
- 300
- Sensitivity
- 92dB
- Low limit
- 55Hz
- Calculated sensitivity †
- 90.5dB
- High limit
- 9000Hz
- Manufacturer sensitivity
- 92dB
- Voice coil
- 51mm
- Diameter
- 208.8mm
- Depth
- 95.0mm
- Cutout
- 181.1mm
- Bolt circle
- 196.8mm
02
Compare
Same-size drivers, compared with the 8PT-8. Clear differences are green when better and red when worse.
This driver8PT-8
Best price
£24.68
Fs
59 Hz
Qts
0.55
Vas
20.1 L
BL
10.2 T·m
Xmax
6.5 mm
Sensitivity
90.5 dB
Power
150 W
Dayton AudioPCS8-4
£29.91 · 21% more, worseFs43 Hz −27%, better
Qts0.49 −11%, better
Vas20.5 L –
BL8.4 T·m −18%, worse
Xmax5 mm −23%, worse
Sensitivity86.7 dB −3.8, worse
Sica8 H 1 CS
£33.41 · 35% more, worseFs50 Hz −16%, better
Qts0.54 –
Vas27.8 L +38%, worse
BL8.7 T·m −14%, worse
Xmax4 mm −38%, worse
Sensitivity89.5 dB −1
SB AudienceBIANCO-8MW125
£37.54 · 52% more, worseFs89 Hz +51%, worse
Qts0.55 –
Vas10.1 L −50%, better
BL11.3 T·m +11%, better
Xmax6.4 mm –
Sensitivity93 dB +2.5, better
Beyma8CMV2
£44.94 · 82% more, worseFs75 Hz +27%, worse
Qts0.52 −5%
Vas14.6 L −27%, better
BL9.6 T·m −6%
Xmax5.7 mm −12%, worse
Sensitivity92.5 dB +2, better
SB AudienceBIANCO-8MW250
£49.00 · 99% more, worseFs74 Hz +25%, worse
Qts0.40 −27%, better
Vas13.8 L −31%, better
BL11 T·m +8%
Xmax6.5 mm –
Sensitivity93 dB +2.5, better
FaitalPRO8FE400
£54.38 · 120% more, worseFs100 Hz +69%, worse
Qts0.53 −4%
Vas9.4 L −53%, better
BL10.5 T·m –
Xmax4.8 mm −27%, worse
Sensitivity94.1 dB +3.6, better
CIAREPM203
£69.50 · 182% more, worseFs91 Hz +54%, worse
Qts0.54 –
Vas10 L −50%, better
BL10.1 T·m –
Xmax4.4 mm −32%, worse
Sensitivity92.7 dB +2.2, better
Dayton AudioRS180-4
£69.58 · 182% more, worseFs38 Hz −35%, better
Qts0.46 −16%, better
Vas21.2 L +5%
BL4.7 T·m −54%, worse
Xmax6 mm −8%
Sensitivity85.1 dB −5.4, worse
Sica8 H 2 CP
£81.97 · 232% more, worseFs39 Hz −34%, better
Qts0.43 −22%, better
Vas35.9 L +79%, worse
BL9.9 T·m –
Xmax6.5 mm –
Sensitivity88.6 dB −1.9
PRV Audio8MR600X
£94.57 · 283% more, worseFs77 Hz +30%, worse
Qts0.40 −27%, better
Vas20.0 L –
BL10.5 T·m +3%
Xmax5.3 mm −19%, worse
Sensitivity95.3 dB +4.8, better
Eighteen Sound8MB500
£97.97 · 297% more, worseFs74 Hz +25%, worse
Qts0.43 −22%, better
Vas21.5 L +7%
BL9 T·m −12%, worse
Xmax6 mm −8%
Sensitivity94.4 dB +3.9, better
B&C8BG51
£110.00 · 346% more, worseFs52 Hz −12%, better
Qts0.40 −27%, better
Vas18 L −10%, better
BL11.8 T·m +16%, better
Xmax6.5 mm –
Sensitivity89.8 dB −0.7
FaitalPRO8PR150
£133.93 · 443% more, worseFs75 Hz +27%, worse
Qts0.48 −13%, better
Vas16.2 L −19%, better
BL10.4 T·m –
Xmax5 mm −23%, worse
Sensitivity93.1 dB +2.6, better
Dayton AudioRSS210HF-4
£144.69 · 486% more, worseFs30 Hz −50%, better
Qts0.57 +4%
Vas23.7 L +18%, worse
BL8.1 T·m −20%, worse
Xmax9 mm +38%, better
Sensitivity81.5 dB −9, worse
Dayton AudioE180HE-44
£159.01 · 544% more, worseFs35 Hz −41%, better
Qts0.46 −16%, better
Vas16.1 L −20%, better
BL9.6 T·m −6%
Xmax14.7 mm +126%, better
Sensitivity83.1 dB −7.4, worse
WavecorSW182BD04
£161.18 · 553% more, worseFs37 Hz −37%, better
Qts0.49 −11%, better
Vas12.7 L −37%, better
BL10.2 T·m –
Xmax7 mm +8%
Sensitivity83.1 dB −7.4, worse
LavoceNBASS08-20
No current priceFs55 Hz −7%
Qts0.48 −13%, better
Vas18.4 L −8%
BL11.3 T·m +11%, better
Xmax6.5 mm –
Sensitivity89.9 dB −0.6
Beyma8CX300FE
No current priceFs89 Hz +51%, worse
Qts0.55 –
Vas10.8 L −46%, better
BL9.6 T·m −6%
Xmax6 mm −8%
Sensitivity92.9 dB +2.4, better
No photo
PHL Audio2001
No current priceFs77 Hz +31%, worse
Qts0.53 −4%
Vas13.8 L −31%, better
BL9.5 T·m −7%
Xmax5.5 mm −15%, worse
Sensitivity92.2 dB +1.7
No photo
PHL Audio2001NDU
No current priceFs77 Hz +31%, worse
Qts0.53 −4%
Vas13.8 L −31%, better
BL9.5 T·m −7%
Xmax5.5 mm −15%, worse
Sensitivity92.2 dB +1.7
CelestionTF0815RE
No current priceFs65 Hz +10%
Qts0.53 −3%
Vas22.1 L +10%, worse
BL8.9 T·m −13%, worse
Xmax5.3 mm −19%, worse
Sensitivity91.7 dB +1.2
PRV Audio8MR360
No current priceFs91 Hz +54%, worse
Qts0.56 –
Vas18.5 L −8%
BL8.3 T·m −19%, worse
Xmax4 mm −38%, worse
Sensitivity95.8 dB +5.3, better
PRV Audio8MR400
No current priceFs78 Hz +33%, worse
Qts0.52 −5%
Vas20.2 L –
BL8.2 T·m −20%, worse
Xmax4 mm −38%, worse
Sensitivity94.4 dB +3.9, better
HiViD8.8MKII
No current priceFs39 Hz −34%, better
Qts0.57 +4%
Vas38.1 L +90%, worse
BL9.6 T·m −6%
Xmax5 mm −23%, worse
Sensitivity87.7 dB −2.8, worse
Tang BandW8-670Q
No current priceFs38 Hz −36%, better
Qts0.46 −16%, better
Vas24.9 L +24%, worse
BL12.3 T·m +20%, better
Xmax7 mm +8%
Sensitivity86.3 dB −4.2, worse
Tang BandW8-670T
No current priceFs40 Hz −32%, better
Qts0.45 −18%, better
Vas23.3 L +16%, worse
BL9.4 T·m −8%
Xmax7.8 mm +21%, better
Sensitivity86.9 dB −3.6, worse
REDCATT81FIND
No current priceFs80 Hz +36%, worse
Qts0.50 −9%
Vas11.3 L −44%, better
BL10.2 T·m –
Xmax2.3 mm −65%, worse
Sensitivity92.4 dB +1.9
No photo
PHL Audio2560-3
No current priceFs79 Hz +34%, worse
Qts0.45 −18%, better
Vas10.7 L −47%, better
BL10.4 T·m –
Xmax5.5 mm −15%, worse
Sensitivity92.3 dB +1.8
Tang BandW8-1747A
No current priceFs30 Hz −49%, better
Qts0.41 −25%, better
Vas23.2 L +15%, worse
BL10.0 T·m –
Xmax8 mm +23%, better
Sensitivity83 dB −7.5, worse
Tune the match
Choose the published values that matter to your design. Size stays matched to this driver.
Qts
Qes
VasL
Xmaxmm
BLTm
- Parts Express4.7 out of 530 ratings · Checked 25 Oct 2026Read reviews on Parts Express
- SoundImports4.5 out of 52 ratings · Checked 25 Oct 2026Read reviews on SoundImports
Each shop collects its own ratings. Bits shows them as published and doesn't verify them.
| Shop | Price | Against the lowest | Stock | Link |
|---|---|---|---|---|
Parts Express Import VAT and duty may apply | £24.68, the lowest price | 240 in stock | Visit shop at Parts Express | |
SoundImports Import VAT and duty may apply | £48.10 | 95% above the lowest price | 5 in stock | Visit shop at SoundImports |
Best price over time
Tracked since 1 Apr