CELESTION CF0820BMB
CELESTION CF0820BMB — 8" / 8 Zoll · Tieftöner · Ferrit
250 W AES - 93 dB - 50 – 6000 Hz - 8 Ω
Art.-Nr.: 42A-CHS-TT-CEL-0002
Documents
CELESTION CF0820BMB — 8" · Woofer
8-inch, cast aluminium chassis, ferrite magnet bass and mid/bass driver
250 W AES · 93 dB Sensitivity · Frequency range 50 Hz – 6000 Hz
Features
- Balanced airflow venting provides enhanced cooling
- Half-roll elastomer surround
Technical data
- Diameter: 8 "
- Voice coil: 2 "
- Power handling: 250 W
- Programme power: 500W
- Sensitivity: 93 dB
- Impedance: 8 Ω
- Magnet: Ferrite
- Chassis: Cast aluminium
- Diaphragm: Impregnated paper
- Surround: Elastomer
- Suspension: Single
- Voice coil former: Glass fibre
- Voice coil wire: Copper-clad aluminium
- Weight: 3.1 kg
- Mounting depth: 108 mm
- Cut-out: 187mm / 7.4in
- Frequency range: 50 – 6000 Hz
Thiele-Small parameters
- Fs: 50.5 Hz
- Qts: 0.366
- Qms: 5.095
- Qes: 0.394
- Vas: 22.42 l
- Xmax: 7.25 mm
- BL: 11.92 Tm
- Re: 5.45 Ω
- Le: 0.78 mH
- Mms: 0.0324 kg
- Sd: 0.0227 m²
Datasheet (PDF) · Manufacturer page
Part no.: 42A-CHS-TT-CEL-0002
Celestion CF0820BMB: 8" bass/mid driver with 7.25 mm Xmax for small vented boxes
With the CF0820BMB, Celestion's CF series offers an 8" driver explicitly designed for bass and lower-mid duty. Key figures: 250 W AES, 93 dB at 8 Ω, rated band 50 to 6000 Hz, a 2" copper-clad aluminium voice coil on a glass-fibre former, ferrite magnet in a cast aluminium frame. The impregnated paper cone sits in a half-roll elastomer surround, and the magnet assembly is vented so that air flows evenly around the coil.
The design differs clearly from its louder midrange sibling, the CF0820M: Fs is 50.5 Hz, Vas 22.42 l, Qts 0.366 and Xmax 7.25 mm. This is a driver that prioritises excursion and extension over efficiency; the 93 dB is the price for 32.4 g of moving mass and an 11.92 Tm motor producing a real bass foundation from an 8" area of 0.0227 m². The EBP of 128 points to a vented box but leaves sealed loading as an option when a subwoofer takes over underneath anyway.
Use and enclosure
As a vented guideline, the parameters give about 19 l tuned to 52 Hz, resulting in a lower cut-off around 54 Hz. That is respectable extension for an 8" driver and makes the CF0820BMB the right mid-woofer for compact two-way boxes, small stage monitors or installation speakers that are meant to work without a subwoofer. Sealed, the numbers come out at about 8.2 l with a 98 Hz in-box resonance, which suits a satellite on a sub. Fine-tune the alignment with the enclosure calculator at 42.audio.
Upwards the rated band reaches 6000 Hz; in two-way operation with a 1" compression driver on a horn from Celestion's horns and waveguides category you cross well below that limit, where the 8" cone still radiates widely. At 108 mm mounting depth and a 187 mm cut-out the driver fits shallow cabinets, and 3.1 kg keeps the box light.
What to look out for
- Xmax 7.25 mm: more travel than usual for 8", usable for extension in a small vented box.
- 93 dB sensitivity: budget a bit more amplifier power than for high-efficiency midranges.
- Half-roll elastomer surround and vented magnet: built for long excursion and continuous duty.
- Mounting depth 108 mm, cut-out 187 mm, 3.1 kg.
- Re 5.45 Ω, Le 0.78 mH: easy 8 Ω load with moderate inductance.
Frequently asked questions
CF0820BMB or CF0820M: which 8" is the right one?
The CF0820BMB is the bass/mid driver with Fs 50.5 Hz, Vas 22.42 l and 7.25 mm Xmax, while the CF0820M is a pure midrange with a far higher resonance frequency and considerably more efficiency. If you need bass out of the box, take the BMB; if the driver only has to cover the midrange in a three-way system, the M is the more efficient choice.
How low does the CF0820BMB go in a vented box?
The guideline is 19 l tuned to 52 Hz with a cut-off around 54 Hz. That covers the bass foundation of a compact box without a subwoofer being mandatory; if you want to go lower, run it sealed in about 8.2 l with a sub.
Which amplifier suits 250 W AES?
An amplifier around the AES rating into 8 Ω is a good match; given the 93 dB it pays to stay towards the upper end of that range. A high-pass filter below the tuning frequency prevents deep transients from exceeding the 7.25 mm Xmax.
Celestion CF0820BMB: manufacturer, spellings and classification
Celestion is the British loudspeaker manufacturer Celestion International Ltd. of Ipswich, England; its PA drivers are also known as Celestion Pro Audio. The CF0820BMB is a 8-inch woofer with ferrite magnet from the CF series, available from 42.audio, Celestion dealer in Germany, with datasheet and full specifications in the driver database.
At 42.audio you get the CELESTION CF0820BMB with all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas Celestion.
Specifications
| Allgemein | |
|---|---|
| Manufacturer | CELESTION |
| Category | Low Frequency |
| Series | CF |
| Magnet | Ferrite |
| Impedance (Ω) | 8 |
| Power handling (W) | 250 |
| Sensitivity (dB) | 93 |
| Frequency from (Hz) | 50 |
| Frequency to (Hz) | 6000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 8 |
| Voice coil (inch) | 2 |
| Mounting depth (mm) | 108 |
| Weight (kg) | 3.1 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5.45 |
| Le (mH) | 0.78 |
| Fs (Hz) | 50.5 |
| Qms | 5.095 |
| Qes | 0.394 |
| Qts | 0.366 |
| Vas (l) | 22.42 |
| Xmax (mm) | 7.25 |
| BL (Tm) | 11.92 |
| Mms (kg) | 0.0324 |
| Sd (m²) | 0.0227 |